| /* |
| * Copyright (C) 2009 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.widget; |
| |
| import android.annotation.ColorInt; |
| import android.annotation.NonNull; |
| import android.compat.annotation.UnsupportedAppUsage; |
| import android.content.Context; |
| import android.content.res.Configuration; |
| import android.content.res.TypedArray; |
| import android.graphics.Canvas; |
| import android.graphics.Rect; |
| import android.os.Build; |
| import android.os.Bundle; |
| import android.os.Parcel; |
| import android.os.Parcelable; |
| import android.util.AttributeSet; |
| import android.util.Log; |
| import android.view.FocusFinder; |
| import android.view.InputDevice; |
| import android.view.KeyEvent; |
| import android.view.MotionEvent; |
| import android.view.VelocityTracker; |
| import android.view.View; |
| import android.view.ViewConfiguration; |
| import android.view.ViewDebug; |
| import android.view.ViewGroup; |
| import android.view.ViewHierarchyEncoder; |
| import android.view.ViewParent; |
| import android.view.accessibility.AccessibilityEvent; |
| import android.view.accessibility.AccessibilityNodeInfo; |
| import android.view.animation.AnimationUtils; |
| import android.view.inspector.InspectableProperty; |
| |
| import com.android.internal.R; |
| import com.android.internal.annotations.VisibleForTesting; |
| |
| import java.util.List; |
| |
| /** |
| * Layout container for a view hierarchy that can be scrolled by the user, |
| * allowing it to be larger than the physical display. A HorizontalScrollView |
| * is a {@link FrameLayout}, meaning you should place one child in it |
| * containing the entire contents to scroll; this child may itself be a layout |
| * manager with a complex hierarchy of objects. A child that is often used |
| * is a {@link LinearLayout} in a horizontal orientation, presenting a horizontal |
| * array of top-level items that the user can scroll through. |
| * |
| * <p>The {@link TextView} class also |
| * takes care of its own scrolling, so does not require a HorizontalScrollView, but |
| * using the two together is possible to achieve the effect of a text view |
| * within a larger container. |
| * |
| * <p>HorizontalScrollView only supports horizontal scrolling. For vertical scrolling, |
| * use either {@link ScrollView} or {@link ListView}. |
| * |
| * @attr ref android.R.styleable#HorizontalScrollView_fillViewport |
| */ |
| public class HorizontalScrollView extends FrameLayout { |
| private static final int ANIMATED_SCROLL_GAP = ScrollView.ANIMATED_SCROLL_GAP; |
| |
| private static final float MAX_SCROLL_FACTOR = ScrollView.MAX_SCROLL_FACTOR; |
| |
| private static final String TAG = "HorizontalScrollView"; |
| |
| /** |
| * When flinging the stretch towards scrolling content, it should destretch quicker than the |
| * fling would normally do. The visual effect of flinging the stretch looks strange as little |
| * appears to happen at first and then when the stretch disappears, the content starts |
| * scrolling quickly. |
| */ |
| private static final float FLING_DESTRETCH_FACTOR = 4f; |
| |
| private long mLastScroll; |
| |
| private final Rect mTempRect = new Rect(); |
| @UnsupportedAppUsage |
| private OverScroller mScroller; |
| /** |
| * Tracks the state of the left edge glow. |
| * |
| * Even though this field is practically final, we cannot make it final because there are apps |
| * setting it via reflection and they need to keep working until they target Q. |
| * @hide |
| */ |
| @NonNull |
| @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 124053130) |
| @VisibleForTesting |
| public EdgeEffect mEdgeGlowLeft; |
| |
| /** |
| * Tracks the state of the bottom edge glow. |
| * |
| * Even though this field is practically final, we cannot make it final because there are apps |
| * setting it via reflection and they need to keep working until they target Q. |
| * @hide |
| */ |
| @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 124052619) |
| @VisibleForTesting |
| public EdgeEffect mEdgeGlowRight; |
| |
| /** |
| * Position of the last motion event. |
| */ |
| @UnsupportedAppUsage |
| private int mLastMotionX; |
| |
| /** |
| * True when the layout has changed but the traversal has not come through yet. |
| * Ideally the view hierarchy would keep track of this for us. |
| */ |
| private boolean mIsLayoutDirty = true; |
| |
| /** |
| * The child to give focus to in the event that a child has requested focus while the |
| * layout is dirty. This prevents the scroll from being wrong if the child has not been |
| * laid out before requesting focus. |
| */ |
| @UnsupportedAppUsage |
| private View mChildToScrollTo = null; |
| |
| /** |
| * True if the user is currently dragging this ScrollView around. This is |
| * not the same as 'is being flinged', which can be checked by |
| * mScroller.isFinished() (flinging begins when the user lifts their finger). |
| */ |
| @UnsupportedAppUsage |
| private boolean mIsBeingDragged = false; |
| |
| /** |
| * Determines speed during touch scrolling |
| */ |
| @UnsupportedAppUsage |
| private VelocityTracker mVelocityTracker; |
| |
| /** |
| * When set to true, the scroll view measure its child to make it fill the currently |
| * visible area. |
| */ |
| @ViewDebug.ExportedProperty(category = "layout") |
| private boolean mFillViewport; |
| |
| /** |
| * Whether arrow scrolling is animated. |
| */ |
| private boolean mSmoothScrollingEnabled = true; |
| |
| private int mTouchSlop; |
| private int mMinimumVelocity; |
| private int mMaximumVelocity; |
| |
| @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553) |
| private int mOverscrollDistance; |
| @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553) |
| private int mOverflingDistance; |
| |
| private float mHorizontalScrollFactor; |
| |
| /** |
| * ID of the active pointer. This is used to retain consistency during |
| * drags/flings if multiple pointers are used. |
| */ |
| private int mActivePointerId = INVALID_POINTER; |
| |
| /** |
| * Sentinel value for no current active pointer. |
| * Used by {@link #mActivePointerId}. |
| */ |
| private static final int INVALID_POINTER = -1; |
| |
| private SavedState mSavedState; |
| |
| public HorizontalScrollView(Context context) { |
| this(context, null); |
| } |
| |
| public HorizontalScrollView(Context context, AttributeSet attrs) { |
| this(context, attrs, com.android.internal.R.attr.horizontalScrollViewStyle); |
| } |
| |
| public HorizontalScrollView(Context context, AttributeSet attrs, int defStyleAttr) { |
| this(context, attrs, defStyleAttr, 0); |
| } |
| |
| public HorizontalScrollView( |
| Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { |
| super(context, attrs, defStyleAttr, defStyleRes); |
| mEdgeGlowLeft = new EdgeEffect(context, attrs); |
| mEdgeGlowRight = new EdgeEffect(context, attrs); |
| initScrollView(); |
| |
| final TypedArray a = context.obtainStyledAttributes( |
| attrs, android.R.styleable.HorizontalScrollView, defStyleAttr, defStyleRes); |
| saveAttributeDataForStyleable(context, android.R.styleable.HorizontalScrollView, |
| attrs, a, defStyleAttr, defStyleRes); |
| |
| setFillViewport(a.getBoolean(android.R.styleable.HorizontalScrollView_fillViewport, false)); |
| |
| a.recycle(); |
| |
| if (context.getResources().getConfiguration().uiMode == Configuration.UI_MODE_TYPE_WATCH) { |
| setRevealOnFocusHint(false); |
| } |
| } |
| |
| @Override |
| protected float getLeftFadingEdgeStrength() { |
| if (getChildCount() == 0) { |
| return 0.0f; |
| } |
| |
| final int length = getHorizontalFadingEdgeLength(); |
| if (mScrollX < length) { |
| return mScrollX / (float) length; |
| } |
| |
| return 1.0f; |
| } |
| |
| @Override |
| protected float getRightFadingEdgeStrength() { |
| if (getChildCount() == 0) { |
| return 0.0f; |
| } |
| |
| final int length = getHorizontalFadingEdgeLength(); |
| final int rightEdge = getWidth() - mPaddingRight; |
| final int span = getChildAt(0).getRight() - mScrollX - rightEdge; |
| if (span < length) { |
| return span / (float) length; |
| } |
| |
| return 1.0f; |
| } |
| |
| /** |
| * Sets the edge effect color for both left and right edge effects. |
| * |
| * @param color The color for the edge effects. |
| * @see #setLeftEdgeEffectColor(int) |
| * @see #setRightEdgeEffectColor(int) |
| * @see #getLeftEdgeEffectColor() |
| * @see #getRightEdgeEffectColor() |
| */ |
| public void setEdgeEffectColor(@ColorInt int color) { |
| setLeftEdgeEffectColor(color); |
| setRightEdgeEffectColor(color); |
| } |
| |
| /** |
| * Sets the right edge effect color. |
| * |
| * @param color The color for the right edge effect. |
| * @see #setLeftEdgeEffectColor(int) |
| * @see #setEdgeEffectColor(int) |
| * @see #getLeftEdgeEffectColor() |
| * @see #getRightEdgeEffectColor() |
| */ |
| public void setRightEdgeEffectColor(@ColorInt int color) { |
| mEdgeGlowRight.setColor(color); |
| } |
| |
| /** |
| * Sets the left edge effect color. |
| * |
| * @param color The color for the left edge effect. |
| * @see #setRightEdgeEffectColor(int) |
| * @see #setEdgeEffectColor(int) |
| * @see #getLeftEdgeEffectColor() |
| * @see #getRightEdgeEffectColor() |
| */ |
| public void setLeftEdgeEffectColor(@ColorInt int color) { |
| mEdgeGlowLeft.setColor(color); |
| } |
| |
| /** |
| * Returns the left edge effect color. |
| * |
| * @return The left edge effect color. |
| * @see #setEdgeEffectColor(int) |
| * @see #setLeftEdgeEffectColor(int) |
| * @see #setRightEdgeEffectColor(int) |
| * @see #getRightEdgeEffectColor() |
| */ |
| @ColorInt |
| public int getLeftEdgeEffectColor() { |
| return mEdgeGlowLeft.getColor(); |
| } |
| |
| /** |
| * Returns the right edge effect color. |
| * |
| * @return The right edge effect color. |
| * @see #setEdgeEffectColor(int) |
| * @see #setLeftEdgeEffectColor(int) |
| * @see #setRightEdgeEffectColor(int) |
| * @see #getLeftEdgeEffectColor() |
| */ |
| @ColorInt |
| public int getRightEdgeEffectColor() { |
| return mEdgeGlowRight.getColor(); |
| } |
| |
| /** |
| * @return The maximum amount this scroll view will scroll in response to |
| * an arrow event. |
| */ |
| public int getMaxScrollAmount() { |
| return (int) (MAX_SCROLL_FACTOR * (mRight - mLeft)); |
| } |
| |
| |
| private void initScrollView() { |
| mScroller = new OverScroller(getContext()); |
| setFocusable(true); |
| setDescendantFocusability(FOCUS_AFTER_DESCENDANTS); |
| setWillNotDraw(false); |
| final ViewConfiguration configuration = ViewConfiguration.get(mContext); |
| mTouchSlop = configuration.getScaledTouchSlop(); |
| mMinimumVelocity = configuration.getScaledMinimumFlingVelocity(); |
| mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); |
| mOverscrollDistance = configuration.getScaledOverscrollDistance(); |
| mOverflingDistance = configuration.getScaledOverflingDistance(); |
| mHorizontalScrollFactor = configuration.getScaledHorizontalScrollFactor(); |
| } |
| |
| @Override |
| public void addView(View child) { |
| if (getChildCount() > 0) { |
| throw new IllegalStateException("HorizontalScrollView can host only one direct child"); |
| } |
| |
| super.addView(child); |
| } |
| |
| @Override |
| public void addView(View child, int index) { |
| if (getChildCount() > 0) { |
| throw new IllegalStateException("HorizontalScrollView can host only one direct child"); |
| } |
| |
| super.addView(child, index); |
| } |
| |
| @Override |
| public void addView(View child, ViewGroup.LayoutParams params) { |
| if (getChildCount() > 0) { |
| throw new IllegalStateException("HorizontalScrollView can host only one direct child"); |
| } |
| |
| super.addView(child, params); |
| } |
| |
| @Override |
| public void addView(View child, int index, ViewGroup.LayoutParams params) { |
| if (getChildCount() > 0) { |
| throw new IllegalStateException("HorizontalScrollView can host only one direct child"); |
| } |
| |
| super.addView(child, index, params); |
| } |
| |
| /** |
| * @return Returns true this HorizontalScrollView can be scrolled |
| */ |
| private boolean canScroll() { |
| View child = getChildAt(0); |
| if (child != null) { |
| int childWidth = child.getWidth(); |
| return getWidth() < childWidth + mPaddingLeft + mPaddingRight ; |
| } |
| return false; |
| } |
| |
| /** |
| * Indicates whether this HorizontalScrollView's content is stretched to |
| * fill the viewport. |
| * |
| * @return True if the content fills the viewport, false otherwise. |
| * |
| * @attr ref android.R.styleable#HorizontalScrollView_fillViewport |
| */ |
| @InspectableProperty |
| public boolean isFillViewport() { |
| return mFillViewport; |
| } |
| |
| /** |
| * Indicates this HorizontalScrollView whether it should stretch its content width |
| * to fill the viewport or not. |
| * |
| * @param fillViewport True to stretch the content's width to the viewport's |
| * boundaries, false otherwise. |
| * |
| * @attr ref android.R.styleable#HorizontalScrollView_fillViewport |
| */ |
| public void setFillViewport(boolean fillViewport) { |
| if (fillViewport != mFillViewport) { |
| mFillViewport = fillViewport; |
| requestLayout(); |
| } |
| } |
| |
| /** |
| * @return Whether arrow scrolling will animate its transition. |
| */ |
| public boolean isSmoothScrollingEnabled() { |
| return mSmoothScrollingEnabled; |
| } |
| |
| /** |
| * Set whether arrow scrolling will animate its transition. |
| * @param smoothScrollingEnabled whether arrow scrolling will animate its transition |
| */ |
| public void setSmoothScrollingEnabled(boolean smoothScrollingEnabled) { |
| mSmoothScrollingEnabled = smoothScrollingEnabled; |
| } |
| |
| @Override |
| protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { |
| super.onMeasure(widthMeasureSpec, heightMeasureSpec); |
| |
| if (!mFillViewport) { |
| return; |
| } |
| |
| final int widthMode = MeasureSpec.getMode(widthMeasureSpec); |
| if (widthMode == MeasureSpec.UNSPECIFIED) { |
| return; |
| } |
| |
| if (getChildCount() > 0) { |
| final View child = getChildAt(0); |
| final int widthPadding; |
| final int heightPadding; |
| final FrameLayout.LayoutParams lp = (LayoutParams) child.getLayoutParams(); |
| final int targetSdkVersion = getContext().getApplicationInfo().targetSdkVersion; |
| if (targetSdkVersion >= Build.VERSION_CODES.M) { |
| widthPadding = mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin; |
| heightPadding = mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin; |
| } else { |
| widthPadding = mPaddingLeft + mPaddingRight; |
| heightPadding = mPaddingTop + mPaddingBottom; |
| } |
| |
| int desiredWidth = getMeasuredWidth() - widthPadding; |
| if (child.getMeasuredWidth() < desiredWidth) { |
| final int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec( |
| desiredWidth, MeasureSpec.EXACTLY); |
| final int childHeightMeasureSpec = getChildMeasureSpec( |
| heightMeasureSpec, heightPadding, lp.height); |
| child.measure(childWidthMeasureSpec, childHeightMeasureSpec); |
| } |
| } |
| } |
| |
| @Override |
| public boolean dispatchKeyEvent(KeyEvent event) { |
| // Let the focused view and/or our descendants get the key first |
| return super.dispatchKeyEvent(event) || executeKeyEvent(event); |
| } |
| |
| /** |
| * You can call this function yourself to have the scroll view perform |
| * scrolling from a key event, just as if the event had been dispatched to |
| * it by the view hierarchy. |
| * |
| * @param event The key event to execute. |
| * @return Return true if the event was handled, else false. |
| */ |
| public boolean executeKeyEvent(KeyEvent event) { |
| mTempRect.setEmpty(); |
| |
| if (!canScroll()) { |
| if (isFocused()) { |
| View currentFocused = findFocus(); |
| if (currentFocused == this) currentFocused = null; |
| View nextFocused = FocusFinder.getInstance().findNextFocus(this, |
| currentFocused, View.FOCUS_RIGHT); |
| return nextFocused != null && nextFocused != this && |
| nextFocused.requestFocus(View.FOCUS_RIGHT); |
| } |
| return false; |
| } |
| |
| boolean handled = false; |
| if (event.getAction() == KeyEvent.ACTION_DOWN) { |
| switch (event.getKeyCode()) { |
| case KeyEvent.KEYCODE_DPAD_LEFT: |
| if (!event.isAltPressed()) { |
| handled = arrowScroll(View.FOCUS_LEFT); |
| } else { |
| handled = fullScroll(View.FOCUS_LEFT); |
| } |
| break; |
| case KeyEvent.KEYCODE_DPAD_RIGHT: |
| if (!event.isAltPressed()) { |
| handled = arrowScroll(View.FOCUS_RIGHT); |
| } else { |
| handled = fullScroll(View.FOCUS_RIGHT); |
| } |
| break; |
| case KeyEvent.KEYCODE_SPACE: |
| pageScroll(event.isShiftPressed() ? View.FOCUS_LEFT : View.FOCUS_RIGHT); |
| break; |
| } |
| } |
| |
| return handled; |
| } |
| |
| private boolean inChild(int x, int y) { |
| if (getChildCount() > 0) { |
| final int scrollX = mScrollX; |
| final View child = getChildAt(0); |
| return !(y < child.getTop() |
| || y >= child.getBottom() |
| || x < child.getLeft() - scrollX |
| || x >= child.getRight() - scrollX); |
| } |
| return false; |
| } |
| |
| private void initOrResetVelocityTracker() { |
| if (mVelocityTracker == null) { |
| mVelocityTracker = VelocityTracker.obtain(); |
| } else { |
| mVelocityTracker.clear(); |
| } |
| } |
| |
| private void initVelocityTrackerIfNotExists() { |
| if (mVelocityTracker == null) { |
| mVelocityTracker = VelocityTracker.obtain(); |
| } |
| } |
| |
| @UnsupportedAppUsage |
| private void recycleVelocityTracker() { |
| if (mVelocityTracker != null) { |
| mVelocityTracker.recycle(); |
| mVelocityTracker = null; |
| } |
| } |
| |
| @Override |
| public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) { |
| if (disallowIntercept) { |
| recycleVelocityTracker(); |
| } |
| super.requestDisallowInterceptTouchEvent(disallowIntercept); |
| } |
| |
| @Override |
| public boolean onInterceptTouchEvent(MotionEvent ev) { |
| /* |
| * This method JUST determines whether we want to intercept the motion. |
| * If we return true, onMotionEvent will be called and we do the actual |
| * scrolling there. |
| */ |
| |
| /* |
| * Shortcut the most recurring case: the user is in the dragging |
| * state and they are moving their finger. We want to intercept this |
| * motion. |
| */ |
| final int action = ev.getAction(); |
| if ((action == MotionEvent.ACTION_MOVE) && (mIsBeingDragged)) { |
| return true; |
| } |
| |
| if (super.onInterceptTouchEvent(ev)) { |
| return true; |
| } |
| |
| switch (action & MotionEvent.ACTION_MASK) { |
| case MotionEvent.ACTION_MOVE: { |
| /* |
| * mIsBeingDragged == false, otherwise the shortcut would have caught it. Check |
| * whether the user has moved far enough from their original down touch. |
| */ |
| |
| /* |
| * Locally do absolute value. mLastMotionX is set to the x value |
| * of the down event. |
| */ |
| final int activePointerId = mActivePointerId; |
| if (activePointerId == INVALID_POINTER) { |
| // If we don't have a valid id, the touch down wasn't on content. |
| break; |
| } |
| |
| final int pointerIndex = ev.findPointerIndex(activePointerId); |
| if (pointerIndex == -1) { |
| Log.e(TAG, "Invalid pointerId=" + activePointerId |
| + " in onInterceptTouchEvent"); |
| break; |
| } |
| |
| final int x = (int) ev.getX(pointerIndex); |
| final int xDiff = (int) Math.abs(x - mLastMotionX); |
| if (xDiff > mTouchSlop) { |
| mIsBeingDragged = true; |
| mLastMotionX = x; |
| initVelocityTrackerIfNotExists(); |
| mVelocityTracker.addMovement(ev); |
| if (mParent != null) mParent.requestDisallowInterceptTouchEvent(true); |
| } |
| break; |
| } |
| |
| case MotionEvent.ACTION_DOWN: { |
| final int x = (int) ev.getX(); |
| if (!inChild((int) x, (int) ev.getY())) { |
| mIsBeingDragged = false; |
| recycleVelocityTracker(); |
| break; |
| } |
| |
| /* |
| * Remember location of down touch. |
| * ACTION_DOWN always refers to pointer index 0. |
| */ |
| mLastMotionX = x; |
| mActivePointerId = ev.getPointerId(0); |
| |
| initOrResetVelocityTracker(); |
| mVelocityTracker.addMovement(ev); |
| |
| /* |
| * If being flinged and user touches the screen, initiate drag; |
| * otherwise don't. mScroller.isFinished should be false when |
| * being flinged. |
| */ |
| mIsBeingDragged = !mScroller.isFinished() || !mEdgeGlowLeft.isFinished() |
| || !mEdgeGlowRight.isFinished(); |
| // Catch the edge effect if it is active. |
| if (!mEdgeGlowLeft.isFinished()) { |
| mEdgeGlowLeft.onPullDistance(0f, 1f - ev.getY() / getHeight()); |
| } |
| if (!mEdgeGlowRight.isFinished()) { |
| mEdgeGlowRight.onPullDistance(0f, ev.getY() / getHeight()); |
| } |
| break; |
| } |
| |
| case MotionEvent.ACTION_CANCEL: |
| case MotionEvent.ACTION_UP: |
| /* Release the drag */ |
| mIsBeingDragged = false; |
| mActivePointerId = INVALID_POINTER; |
| if (mScroller.springBack(mScrollX, mScrollY, 0, getScrollRange(), 0, 0)) { |
| postInvalidateOnAnimation(); |
| } |
| break; |
| case MotionEvent.ACTION_POINTER_DOWN: { |
| final int index = ev.getActionIndex(); |
| mLastMotionX = (int) ev.getX(index); |
| mActivePointerId = ev.getPointerId(index); |
| break; |
| } |
| case MotionEvent.ACTION_POINTER_UP: |
| onSecondaryPointerUp(ev); |
| mLastMotionX = (int) ev.getX(ev.findPointerIndex(mActivePointerId)); |
| break; |
| } |
| |
| /* |
| * The only time we want to intercept motion events is if we are in the |
| * drag mode. |
| */ |
| return mIsBeingDragged; |
| } |
| |
| @Override |
| public boolean onTouchEvent(MotionEvent ev) { |
| initVelocityTrackerIfNotExists(); |
| mVelocityTracker.addMovement(ev); |
| |
| final int action = ev.getAction(); |
| |
| switch (action & MotionEvent.ACTION_MASK) { |
| case MotionEvent.ACTION_DOWN: { |
| if (getChildCount() == 0) { |
| return false; |
| } |
| if (!mScroller.isFinished()) { |
| final ViewParent parent = getParent(); |
| if (parent != null) { |
| parent.requestDisallowInterceptTouchEvent(true); |
| } |
| } |
| |
| /* |
| * If being flinged and user touches, stop the fling. isFinished |
| * will be false if being flinged. |
| */ |
| if (!mScroller.isFinished()) { |
| mScroller.abortAnimation(); |
| } |
| |
| // Remember where the motion event started |
| mLastMotionX = (int) ev.getX(); |
| mActivePointerId = ev.getPointerId(0); |
| break; |
| } |
| case MotionEvent.ACTION_MOVE: |
| final int activePointerIndex = ev.findPointerIndex(mActivePointerId); |
| if (activePointerIndex == -1) { |
| Log.e(TAG, "Invalid pointerId=" + mActivePointerId + " in onTouchEvent"); |
| break; |
| } |
| |
| final int x = (int) ev.getX(activePointerIndex); |
| int deltaX = mLastMotionX - x; |
| if (!mIsBeingDragged && Math.abs(deltaX) > mTouchSlop) { |
| final ViewParent parent = getParent(); |
| if (parent != null) { |
| parent.requestDisallowInterceptTouchEvent(true); |
| } |
| mIsBeingDragged = true; |
| if (deltaX > 0) { |
| deltaX -= mTouchSlop; |
| } else { |
| deltaX += mTouchSlop; |
| } |
| } |
| if (mIsBeingDragged) { |
| // Scroll to follow the motion event |
| mLastMotionX = x; |
| |
| final int oldX = mScrollX; |
| final int range = getScrollRange(); |
| final int overscrollMode = getOverScrollMode(); |
| final boolean canOverscroll = overscrollMode == OVER_SCROLL_ALWAYS || |
| (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0); |
| |
| final float displacement = ev.getY(activePointerIndex) / getHeight(); |
| if (canOverscroll) { |
| int consumed = 0; |
| if (deltaX < 0 && mEdgeGlowRight.getDistance() != 0f) { |
| consumed = Math.round(getWidth() |
| * mEdgeGlowRight.onPullDistance((float) deltaX / getWidth(), |
| displacement)); |
| } else if (deltaX > 0 && mEdgeGlowLeft.getDistance() != 0f) { |
| consumed = Math.round(-getWidth() |
| * mEdgeGlowLeft.onPullDistance((float) -deltaX / getWidth(), |
| 1 - displacement)); |
| } |
| deltaX -= consumed; |
| } |
| |
| // Calling overScrollBy will call onOverScrolled, which |
| // calls onScrollChanged if applicable. |
| overScrollBy(deltaX, 0, mScrollX, 0, range, 0, |
| mOverscrollDistance, 0, true); |
| |
| if (canOverscroll && deltaX != 0f) { |
| final int pulledToX = oldX + deltaX; |
| if (pulledToX < 0) { |
| mEdgeGlowLeft.onPullDistance((float) -deltaX / getWidth(), |
| 1.f - displacement); |
| if (!mEdgeGlowRight.isFinished()) { |
| mEdgeGlowRight.onRelease(); |
| } |
| } else if (pulledToX > range) { |
| mEdgeGlowRight.onPullDistance((float) deltaX / getWidth(), |
| displacement); |
| if (!mEdgeGlowLeft.isFinished()) { |
| mEdgeGlowLeft.onRelease(); |
| } |
| } |
| if (shouldDisplayEdgeEffects() |
| && (!mEdgeGlowLeft.isFinished() || !mEdgeGlowRight.isFinished())) { |
| postInvalidateOnAnimation(); |
| } |
| } |
| } |
| break; |
| case MotionEvent.ACTION_UP: |
| if (mIsBeingDragged) { |
| final VelocityTracker velocityTracker = mVelocityTracker; |
| velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); |
| int initialVelocity = (int) velocityTracker.getXVelocity(mActivePointerId); |
| |
| if (getChildCount() > 0) { |
| if ((Math.abs(initialVelocity) > mMinimumVelocity)) { |
| fling(-initialVelocity); |
| } else { |
| if (mScroller.springBack(mScrollX, mScrollY, 0, |
| getScrollRange(), 0, 0)) { |
| postInvalidateOnAnimation(); |
| } |
| } |
| } |
| |
| mActivePointerId = INVALID_POINTER; |
| mIsBeingDragged = false; |
| recycleVelocityTracker(); |
| |
| if (shouldDisplayEdgeEffects()) { |
| mEdgeGlowLeft.onRelease(); |
| mEdgeGlowRight.onRelease(); |
| } |
| } |
| break; |
| case MotionEvent.ACTION_CANCEL: |
| if (mIsBeingDragged && getChildCount() > 0) { |
| if (mScroller.springBack(mScrollX, mScrollY, 0, getScrollRange(), 0, 0)) { |
| postInvalidateOnAnimation(); |
| } |
| mActivePointerId = INVALID_POINTER; |
| mIsBeingDragged = false; |
| recycleVelocityTracker(); |
| |
| if (shouldDisplayEdgeEffects()) { |
| mEdgeGlowLeft.onRelease(); |
| mEdgeGlowRight.onRelease(); |
| } |
| } |
| break; |
| case MotionEvent.ACTION_POINTER_UP: |
| onSecondaryPointerUp(ev); |
| break; |
| } |
| return true; |
| } |
| |
| private void onSecondaryPointerUp(MotionEvent ev) { |
| final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> |
| MotionEvent.ACTION_POINTER_INDEX_SHIFT; |
| final int pointerId = ev.getPointerId(pointerIndex); |
| if (pointerId == mActivePointerId) { |
| // This was our active pointer going up. Choose a new |
| // active pointer and adjust accordingly. |
| // TODO: Make this decision more intelligent. |
| final int newPointerIndex = pointerIndex == 0 ? 1 : 0; |
| mLastMotionX = (int) ev.getX(newPointerIndex); |
| mActivePointerId = ev.getPointerId(newPointerIndex); |
| if (mVelocityTracker != null) { |
| mVelocityTracker.clear(); |
| } |
| } |
| } |
| |
| @Override |
| public boolean onGenericMotionEvent(MotionEvent event) { |
| switch (event.getAction()) { |
| case MotionEvent.ACTION_SCROLL: { |
| if (!mIsBeingDragged) { |
| final float axisValue; |
| if (event.isFromSource(InputDevice.SOURCE_CLASS_POINTER)) { |
| if ((event.getMetaState() & KeyEvent.META_SHIFT_ON) != 0) { |
| axisValue = -event.getAxisValue(MotionEvent.AXIS_VSCROLL); |
| } else { |
| axisValue = event.getAxisValue(MotionEvent.AXIS_HSCROLL); |
| } |
| } else if (event.isFromSource(InputDevice.SOURCE_ROTARY_ENCODER)) { |
| axisValue = event.getAxisValue(MotionEvent.AXIS_SCROLL); |
| } else { |
| axisValue = 0; |
| } |
| |
| final int delta = Math.round(axisValue * mHorizontalScrollFactor); |
| if (delta != 0) { |
| final int range = getScrollRange(); |
| int oldScrollX = mScrollX; |
| int newScrollX = oldScrollX + delta; |
| |
| final int overscrollMode = getOverScrollMode(); |
| boolean canOverscroll = !event.isFromSource(InputDevice.SOURCE_MOUSE) |
| && (overscrollMode == OVER_SCROLL_ALWAYS |
| || (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0)); |
| boolean absorbed = false; |
| |
| if (newScrollX < 0) { |
| if (canOverscroll) { |
| mEdgeGlowLeft.onPullDistance(-(float) newScrollX / getWidth(), |
| 0.5f); |
| mEdgeGlowLeft.onRelease(); |
| invalidate(); |
| absorbed = true; |
| } |
| newScrollX = 0; |
| } else if (newScrollX > range) { |
| if (canOverscroll) { |
| mEdgeGlowRight.onPullDistance( |
| (float) (newScrollX - range) / getWidth(), 0.5f); |
| mEdgeGlowRight.onRelease(); |
| invalidate(); |
| absorbed = true; |
| } |
| newScrollX = range; |
| } |
| if (newScrollX != oldScrollX) { |
| super.scrollTo(newScrollX, mScrollY); |
| return true; |
| } |
| if (absorbed) { |
| return true; |
| } |
| } |
| } |
| } |
| } |
| return super.onGenericMotionEvent(event); |
| } |
| |
| @Override |
| public boolean shouldDelayChildPressedState() { |
| return true; |
| } |
| |
| @Override |
| protected void onOverScrolled(int scrollX, int scrollY, |
| boolean clampedX, boolean clampedY) { |
| // Treat animating scrolls differently; see #computeScroll() for why. |
| if (!mScroller.isFinished()) { |
| final int oldX = mScrollX; |
| final int oldY = mScrollY; |
| mScrollX = scrollX; |
| mScrollY = scrollY; |
| invalidateParentIfNeeded(); |
| onScrollChanged(mScrollX, mScrollY, oldX, oldY); |
| if (clampedX) { |
| mScroller.springBack(mScrollX, mScrollY, 0, getScrollRange(), 0, 0); |
| } |
| } else { |
| super.scrollTo(scrollX, scrollY); |
| } |
| |
| awakenScrollBars(); |
| } |
| |
| /** @hide */ |
| @Override |
| public boolean performAccessibilityActionInternal(int action, Bundle arguments) { |
| if (super.performAccessibilityActionInternal(action, arguments)) { |
| return true; |
| } |
| switch (action) { |
| case AccessibilityNodeInfo.ACTION_SCROLL_FORWARD: |
| case R.id.accessibilityActionScrollRight: { |
| if (!isEnabled()) { |
| return false; |
| } |
| final int viewportWidth = getWidth() - mPaddingLeft - mPaddingRight; |
| final int targetScrollX = Math.min(mScrollX + viewportWidth, getScrollRange()); |
| if (targetScrollX != mScrollX) { |
| smoothScrollTo(targetScrollX, 0); |
| return true; |
| } |
| } return false; |
| case AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD: |
| case R.id.accessibilityActionScrollLeft: { |
| if (!isEnabled()) { |
| return false; |
| } |
| final int viewportWidth = getWidth() - mPaddingLeft - mPaddingRight; |
| final int targetScrollX = Math.max(0, mScrollX - viewportWidth); |
| if (targetScrollX != mScrollX) { |
| smoothScrollTo(targetScrollX, 0); |
| return true; |
| } |
| } return false; |
| } |
| return false; |
| } |
| |
| @Override |
| public CharSequence getAccessibilityClassName() { |
| return HorizontalScrollView.class.getName(); |
| } |
| |
| /** @hide */ |
| @Override |
| public void onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info) { |
| super.onInitializeAccessibilityNodeInfoInternal(info); |
| final int scrollRange = getScrollRange(); |
| if (scrollRange > 0) { |
| info.setScrollable(true); |
| if (isEnabled() && mScrollX > 0) { |
| info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_BACKWARD); |
| info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_LEFT); |
| } |
| if (isEnabled() && mScrollX < scrollRange) { |
| info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_FORWARD); |
| info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_RIGHT); |
| } |
| } |
| } |
| |
| /** @hide */ |
| @Override |
| public void onInitializeAccessibilityEventInternal(AccessibilityEvent event) { |
| super.onInitializeAccessibilityEventInternal(event); |
| event.setScrollable(getScrollRange() > 0); |
| event.setMaxScrollX(getScrollRange()); |
| event.setMaxScrollY(mScrollY); |
| } |
| |
| private int getScrollRange() { |
| int scrollRange = 0; |
| if (getChildCount() > 0) { |
| View child = getChildAt(0); |
| scrollRange = Math.max(0, |
| child.getWidth() - (getWidth() - mPaddingLeft - mPaddingRight)); |
| } |
| return scrollRange; |
| } |
| |
| /** |
| * <p> |
| * Finds the next focusable component that fits in this View's bounds |
| * (excluding fading edges) pretending that this View's left is located at |
| * the parameter left. |
| * </p> |
| * |
| * @param leftFocus look for a candidate is the one at the left of the bounds |
| * if leftFocus is true, or at the right of the bounds if leftFocus |
| * is false |
| * @param left the left offset of the bounds in which a focusable must be |
| * found (the fading edge is assumed to start at this position) |
| * @param preferredFocusable the View that has highest priority and will be |
| * returned if it is within my bounds (null is valid) |
| * @return the next focusable component in the bounds or null if none can be found |
| */ |
| private View findFocusableViewInMyBounds(final boolean leftFocus, |
| final int left, View preferredFocusable) { |
| /* |
| * The fading edge's transparent side should be considered for focus |
| * since it's mostly visible, so we divide the actual fading edge length |
| * by 2. |
| */ |
| final int fadingEdgeLength = getHorizontalFadingEdgeLength() / 2; |
| final int leftWithoutFadingEdge = left + fadingEdgeLength; |
| final int rightWithoutFadingEdge = left + getWidth() - fadingEdgeLength; |
| |
| if ((preferredFocusable != null) |
| && (preferredFocusable.getLeft() < rightWithoutFadingEdge) |
| && (preferredFocusable.getRight() > leftWithoutFadingEdge)) { |
| return preferredFocusable; |
| } |
| |
| return findFocusableViewInBounds(leftFocus, leftWithoutFadingEdge, |
| rightWithoutFadingEdge); |
| } |
| |
| /** |
| * <p> |
| * Finds the next focusable component that fits in the specified bounds. |
| * </p> |
| * |
| * @param leftFocus look for a candidate is the one at the left of the bounds |
| * if leftFocus is true, or at the right of the bounds if |
| * leftFocus is false |
| * @param left the left offset of the bounds in which a focusable must be |
| * found |
| * @param right the right offset of the bounds in which a focusable must |
| * be found |
| * @return the next focusable component in the bounds or null if none can |
| * be found |
| */ |
| private View findFocusableViewInBounds(boolean leftFocus, int left, int right) { |
| |
| List<View> focusables = getFocusables(View.FOCUS_FORWARD); |
| View focusCandidate = null; |
| |
| /* |
| * A fully contained focusable is one where its left is below the bound's |
| * left, and its right is above the bound's right. A partially |
| * contained focusable is one where some part of it is within the |
| * bounds, but it also has some part that is not within bounds. A fully contained |
| * focusable is preferred to a partially contained focusable. |
| */ |
| boolean foundFullyContainedFocusable = false; |
| |
| int count = focusables.size(); |
| for (int i = 0; i < count; i++) { |
| View view = focusables.get(i); |
| int viewLeft = view.getLeft(); |
| int viewRight = view.getRight(); |
| |
| if (left < viewRight && viewLeft < right) { |
| /* |
| * the focusable is in the target area, it is a candidate for |
| * focusing |
| */ |
| |
| final boolean viewIsFullyContained = (left < viewLeft) && |
| (viewRight < right); |
| |
| if (focusCandidate == null) { |
| /* No candidate, take this one */ |
| focusCandidate = view; |
| foundFullyContainedFocusable = viewIsFullyContained; |
| } else { |
| final boolean viewIsCloserToBoundary = |
| (leftFocus && viewLeft < focusCandidate.getLeft()) || |
| (!leftFocus && viewRight > focusCandidate.getRight()); |
| |
| if (foundFullyContainedFocusable) { |
| if (viewIsFullyContained && viewIsCloserToBoundary) { |
| /* |
| * We're dealing with only fully contained views, so |
| * it has to be closer to the boundary to beat our |
| * candidate |
| */ |
| focusCandidate = view; |
| } |
| } else { |
| if (viewIsFullyContained) { |
| /* Any fully contained view beats a partially contained view */ |
| focusCandidate = view; |
| foundFullyContainedFocusable = true; |
| } else if (viewIsCloserToBoundary) { |
| /* |
| * Partially contained view beats another partially |
| * contained view if it's closer |
| */ |
| focusCandidate = view; |
| } |
| } |
| } |
| } |
| } |
| |
| return focusCandidate; |
| } |
| |
| /** |
| * <p>Handles scrolling in response to a "page up/down" shortcut press. This |
| * method will scroll the view by one page left or right and give the focus |
| * to the leftmost/rightmost component in the new visible area. If no |
| * component is a good candidate for focus, this scrollview reclaims the |
| * focus.</p> |
| * |
| * @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT} |
| * to go one page left or {@link android.view.View#FOCUS_RIGHT} |
| * to go one page right |
| * @return true if the key event is consumed by this method, false otherwise |
| */ |
| public boolean pageScroll(int direction) { |
| boolean right = direction == View.FOCUS_RIGHT; |
| int width = getWidth(); |
| |
| if (right) { |
| mTempRect.left = getScrollX() + width; |
| int count = getChildCount(); |
| if (count > 0) { |
| View view = getChildAt(0); |
| if (mTempRect.left + width > view.getRight()) { |
| mTempRect.left = view.getRight() - width; |
| } |
| } |
| } else { |
| mTempRect.left = getScrollX() - width; |
| if (mTempRect.left < 0) { |
| mTempRect.left = 0; |
| } |
| } |
| mTempRect.right = mTempRect.left + width; |
| |
| return scrollAndFocus(direction, mTempRect.left, mTempRect.right); |
| } |
| |
| /** |
| * <p>Handles scrolling in response to a "home/end" shortcut press. This |
| * method will scroll the view to the left or right and give the focus |
| * to the leftmost/rightmost component in the new visible area. If no |
| * component is a good candidate for focus, this scrollview reclaims the |
| * focus.</p> |
| * |
| * @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT} |
| * to go the left of the view or {@link android.view.View#FOCUS_RIGHT} |
| * to go the right |
| * @return true if the key event is consumed by this method, false otherwise |
| */ |
| public boolean fullScroll(int direction) { |
| boolean right = direction == View.FOCUS_RIGHT; |
| int width = getWidth(); |
| |
| mTempRect.left = 0; |
| mTempRect.right = width; |
| |
| if (right) { |
| int count = getChildCount(); |
| if (count > 0) { |
| View view = getChildAt(0); |
| mTempRect.right = view.getRight(); |
| mTempRect.left = mTempRect.right - width; |
| } |
| } |
| |
| return scrollAndFocus(direction, mTempRect.left, mTempRect.right); |
| } |
| |
| /** |
| * <p>Scrolls the view to make the area defined by <code>left</code> and |
| * <code>right</code> visible. This method attempts to give the focus |
| * to a component visible in this area. If no component can be focused in |
| * the new visible area, the focus is reclaimed by this scrollview.</p> |
| * |
| * @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT} |
| * to go left {@link android.view.View#FOCUS_RIGHT} to right |
| * @param left the left offset of the new area to be made visible |
| * @param right the right offset of the new area to be made visible |
| * @return true if the key event is consumed by this method, false otherwise |
| */ |
| private boolean scrollAndFocus(int direction, int left, int right) { |
| boolean handled = true; |
| |
| int width = getWidth(); |
| int containerLeft = getScrollX(); |
| int containerRight = containerLeft + width; |
| boolean goLeft = direction == View.FOCUS_LEFT; |
| |
| View newFocused = findFocusableViewInBounds(goLeft, left, right); |
| if (newFocused == null) { |
| newFocused = this; |
| } |
| |
| if (left >= containerLeft && right <= containerRight) { |
| handled = false; |
| } else { |
| int delta = goLeft ? (left - containerLeft) : (right - containerRight); |
| doScrollX(delta); |
| } |
| |
| if (newFocused != findFocus()) newFocused.requestFocus(direction); |
| |
| return handled; |
| } |
| |
| /** |
| * Handle scrolling in response to a left or right arrow click. |
| * |
| * @param direction The direction corresponding to the arrow key that was |
| * pressed |
| * @return True if we consumed the event, false otherwise |
| */ |
| public boolean arrowScroll(int direction) { |
| |
| View currentFocused = findFocus(); |
| if (currentFocused == this) currentFocused = null; |
| |
| View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, direction); |
| |
| final int maxJump = getMaxScrollAmount(); |
| |
| if (nextFocused != null && isWithinDeltaOfScreen(nextFocused, maxJump)) { |
| nextFocused.getDrawingRect(mTempRect); |
| offsetDescendantRectToMyCoords(nextFocused, mTempRect); |
| int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); |
| doScrollX(scrollDelta); |
| nextFocused.requestFocus(direction); |
| } else { |
| // no new focus |
| int scrollDelta = maxJump; |
| |
| if (direction == View.FOCUS_LEFT && getScrollX() < scrollDelta) { |
| scrollDelta = getScrollX(); |
| } else if (direction == View.FOCUS_RIGHT && getChildCount() > 0) { |
| |
| int daRight = getChildAt(0).getRight(); |
| |
| int screenRight = getScrollX() + getWidth(); |
| |
| if (daRight - screenRight < maxJump) { |
| scrollDelta = daRight - screenRight; |
| } |
| } |
| if (scrollDelta == 0) { |
| return false; |
| } |
| doScrollX(direction == View.FOCUS_RIGHT ? scrollDelta : -scrollDelta); |
| } |
| |
| if (currentFocused != null && currentFocused.isFocused() |
| && isOffScreen(currentFocused)) { |
| // previously focused item still has focus and is off screen, give |
| // it up (take it back to ourselves) |
| // (also, need to temporarily force FOCUS_BEFORE_DESCENDANTS so we are |
| // sure to |
| // get it) |
| final int descendantFocusability = getDescendantFocusability(); // save |
| setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS); |
| requestFocus(); |
| setDescendantFocusability(descendantFocusability); // restore |
| } |
| return true; |
| } |
| |
| /** |
| * @return whether the descendant of this scroll view is scrolled off |
| * screen. |
| */ |
| private boolean isOffScreen(View descendant) { |
| return !isWithinDeltaOfScreen(descendant, 0); |
| } |
| |
| /** |
| * @return whether the descendant of this scroll view is within delta |
| * pixels of being on the screen. |
| */ |
| private boolean isWithinDeltaOfScreen(View descendant, int delta) { |
| descendant.getDrawingRect(mTempRect); |
| offsetDescendantRectToMyCoords(descendant, mTempRect); |
| |
| return (mTempRect.right + delta) >= getScrollX() |
| && (mTempRect.left - delta) <= (getScrollX() + getWidth()); |
| } |
| |
| /** |
| * Smooth scroll by a X delta |
| * |
| * @param delta the number of pixels to scroll by on the X axis |
| */ |
| private void doScrollX(int delta) { |
| if (delta != 0) { |
| if (mSmoothScrollingEnabled) { |
| smoothScrollBy(delta, 0); |
| } else { |
| scrollBy(delta, 0); |
| } |
| } |
| } |
| |
| /** |
| * Like {@link View#scrollBy}, but scroll smoothly instead of immediately. |
| * |
| * @param dx the number of pixels to scroll by on the X axis |
| * @param dy the number of pixels to scroll by on the Y axis |
| */ |
| public final void smoothScrollBy(int dx, int dy) { |
| if (getChildCount() == 0) { |
| // Nothing to do. |
| return; |
| } |
| long duration = AnimationUtils.currentAnimationTimeMillis() - mLastScroll; |
| if (duration > ANIMATED_SCROLL_GAP) { |
| final int width = getWidth() - mPaddingRight - mPaddingLeft; |
| final int right = getChildAt(0).getWidth(); |
| final int maxX = Math.max(0, right - width); |
| final int scrollX = mScrollX; |
| dx = Math.max(0, Math.min(scrollX + dx, maxX)) - scrollX; |
| |
| mScroller.startScroll(scrollX, mScrollY, dx, 0); |
| postInvalidateOnAnimation(); |
| } else { |
| if (!mScroller.isFinished()) { |
| mScroller.abortAnimation(); |
| } |
| scrollBy(dx, dy); |
| } |
| mLastScroll = AnimationUtils.currentAnimationTimeMillis(); |
| } |
| |
| /** |
| * Like {@link #scrollTo}, but scroll smoothly instead of immediately. |
| * |
| * @param x the position where to scroll on the X axis |
| * @param y the position where to scroll on the Y axis |
| */ |
| public final void smoothScrollTo(int x, int y) { |
| smoothScrollBy(x - mScrollX, y - mScrollY); |
| } |
| |
| /** |
| * <p>The scroll range of a scroll view is the overall width of all of its |
| * children.</p> |
| */ |
| @Override |
| protected int computeHorizontalScrollRange() { |
| final int count = getChildCount(); |
| final int contentWidth = getWidth() - mPaddingLeft - mPaddingRight; |
| if (count == 0) { |
| return contentWidth; |
| } |
| |
| int scrollRange = getChildAt(0).getRight(); |
| final int scrollX = mScrollX; |
| final int overscrollRight = Math.max(0, scrollRange - contentWidth); |
| if (scrollX < 0) { |
| scrollRange -= scrollX; |
| } else if (scrollX > overscrollRight) { |
| scrollRange += scrollX - overscrollRight; |
| } |
| |
| return scrollRange; |
| } |
| |
| @Override |
| protected int computeHorizontalScrollOffset() { |
| return Math.max(0, super.computeHorizontalScrollOffset()); |
| } |
| |
| @Override |
| protected void measureChild(View child, int parentWidthMeasureSpec, |
| int parentHeightMeasureSpec) { |
| ViewGroup.LayoutParams lp = child.getLayoutParams(); |
| |
| final int horizontalPadding = mPaddingLeft + mPaddingRight; |
| final int childWidthMeasureSpec = MeasureSpec.makeSafeMeasureSpec( |
| Math.max(0, MeasureSpec.getSize(parentWidthMeasureSpec) - horizontalPadding), |
| MeasureSpec.UNSPECIFIED); |
| |
| final int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec, |
| mPaddingTop + mPaddingBottom, lp.height); |
| child.measure(childWidthMeasureSpec, childHeightMeasureSpec); |
| } |
| |
| @Override |
| protected void measureChildWithMargins(View child, int parentWidthMeasureSpec, int widthUsed, |
| int parentHeightMeasureSpec, int heightUsed) { |
| final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams(); |
| |
| final int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec, |
| mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin |
| + heightUsed, lp.height); |
| final int usedTotal = mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin + |
| widthUsed; |
| final int childWidthMeasureSpec = MeasureSpec.makeSafeMeasureSpec( |
| Math.max(0, MeasureSpec.getSize(parentWidthMeasureSpec) - usedTotal), |
| MeasureSpec.UNSPECIFIED); |
| |
| child.measure(childWidthMeasureSpec, childHeightMeasureSpec); |
| } |
| |
| @Override |
| public void computeScroll() { |
| if (mScroller.computeScrollOffset()) { |
| // This is called at drawing time by ViewGroup. We don't want to |
| // re-show the scrollbars at this point, which scrollTo will do, |
| // so we replicate most of scrollTo here. |
| // |
| // It's a little odd to call onScrollChanged from inside the drawing. |
| // |
| // It is, except when you remember that computeScroll() is used to |
| // animate scrolling. So unless we want to defer the onScrollChanged() |
| // until the end of the animated scrolling, we don't really have a |
| // choice here. |
| // |
| // I agree. The alternative, which I think would be worse, is to post |
| // something and tell the subclasses later. This is bad because there |
| // will be a window where mScrollX/Y is different from what the app |
| // thinks it is. |
| // |
| int oldX = mScrollX; |
| int oldY = mScrollY; |
| int x = mScroller.getCurrX(); |
| int y = mScroller.getCurrY(); |
| int deltaX = consumeFlingInStretch(x - oldX); |
| |
| if (deltaX != 0 || oldY != y) { |
| final int range = getScrollRange(); |
| final int overscrollMode = getOverScrollMode(); |
| final boolean canOverscroll = overscrollMode == OVER_SCROLL_ALWAYS || |
| (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0); |
| |
| overScrollBy(deltaX, y - oldY, oldX, oldY, range, 0, |
| mOverflingDistance, 0, false); |
| onScrollChanged(mScrollX, mScrollY, oldX, oldY); |
| |
| if (canOverscroll && deltaX != 0) { |
| if (x < 0 && oldX >= 0) { |
| mEdgeGlowLeft.onAbsorb((int) mScroller.getCurrVelocity()); |
| } else if (x > range && oldX <= range) { |
| mEdgeGlowRight.onAbsorb((int) mScroller.getCurrVelocity()); |
| } |
| } |
| } |
| |
| if (!awakenScrollBars()) { |
| postInvalidateOnAnimation(); |
| } |
| } |
| } |
| |
| /** |
| * Used by consumeFlingInHorizontalStretch() and consumeFlinInVerticalStretch() for |
| * consuming deltas from EdgeEffects |
| * @param unconsumed The unconsumed delta that the EdgeEffets may consume |
| * @return The unconsumed delta after the EdgeEffects have had an opportunity to consume. |
| */ |
| private int consumeFlingInStretch(int unconsumed) { |
| if (unconsumed > 0 && mEdgeGlowLeft != null && mEdgeGlowLeft.getDistance() != 0f) { |
| int size = getWidth(); |
| float deltaDistance = -unconsumed * FLING_DESTRETCH_FACTOR / size; |
| int consumed = Math.round(-size / FLING_DESTRETCH_FACTOR |
| * mEdgeGlowLeft.onPullDistance(deltaDistance, 0.5f)); |
| if (consumed != unconsumed) { |
| mEdgeGlowLeft.finish(); |
| } |
| return unconsumed - consumed; |
| } |
| if (unconsumed < 0 && mEdgeGlowRight != null && mEdgeGlowRight.getDistance() != 0f) { |
| int size = getWidth(); |
| float deltaDistance = unconsumed * FLING_DESTRETCH_FACTOR / size; |
| int consumed = Math.round(size / FLING_DESTRETCH_FACTOR |
| * mEdgeGlowRight.onPullDistance(deltaDistance, 0.5f)); |
| if (consumed != unconsumed) { |
| mEdgeGlowRight.finish(); |
| } |
| return unconsumed - consumed; |
| } |
| return unconsumed; |
| } |
| |
| /** |
| * Scrolls the view to the given child. |
| * |
| * @param child the View to scroll to |
| */ |
| private void scrollToChild(View child) { |
| child.getDrawingRect(mTempRect); |
| |
| /* Offset from child's local coordinates to ScrollView coordinates */ |
| offsetDescendantRectToMyCoords(child, mTempRect); |
| |
| int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); |
| |
| if (scrollDelta != 0) { |
| scrollBy(scrollDelta, 0); |
| } |
| } |
| |
| /** |
| * If rect is off screen, scroll just enough to get it (or at least the |
| * first screen size chunk of it) on screen. |
| * |
| * @param rect The rectangle. |
| * @param immediate True to scroll immediately without animation |
| * @return true if scrolling was performed |
| */ |
| private boolean scrollToChildRect(Rect rect, boolean immediate) { |
| final int delta = computeScrollDeltaToGetChildRectOnScreen(rect); |
| final boolean scroll = delta != 0; |
| if (scroll) { |
| if (immediate) { |
| scrollBy(delta, 0); |
| } else { |
| smoothScrollBy(delta, 0); |
| } |
| } |
| return scroll; |
| } |
| |
| /** |
| * Compute the amount to scroll in the X direction in order to get |
| * a rectangle completely on the screen (or, if taller than the screen, |
| * at least the first screen size chunk of it). |
| * |
| * @param rect The rect. |
| * @return The scroll delta. |
| */ |
| protected int computeScrollDeltaToGetChildRectOnScreen(Rect rect) { |
| if (getChildCount() == 0) return 0; |
| |
| int width = getWidth(); |
| int screenLeft = getScrollX(); |
| int screenRight = screenLeft + width; |
| |
| int fadingEdge = getHorizontalFadingEdgeLength(); |
| |
| // leave room for left fading edge as long as rect isn't at very left |
| if (rect.left > 0) { |
| screenLeft += fadingEdge; |
| } |
| |
| // leave room for right fading edge as long as rect isn't at very right |
| if (rect.right < getChildAt(0).getWidth()) { |
| screenRight -= fadingEdge; |
| } |
| |
| int scrollXDelta = 0; |
| |
| if (rect.right > screenRight && rect.left > screenLeft) { |
| // need to move right to get it in view: move right just enough so |
| // that the entire rectangle is in view (or at least the first |
| // screen size chunk). |
| |
| if (rect.width() > width) { |
| // just enough to get screen size chunk on |
| scrollXDelta += (rect.left - screenLeft); |
| } else { |
| // get entire rect at right of screen |
| scrollXDelta += (rect.right - screenRight); |
| } |
| |
| // make sure we aren't scrolling beyond the end of our content |
| int right = getChildAt(0).getRight(); |
| int distanceToRight = right - screenRight; |
| scrollXDelta = Math.min(scrollXDelta, distanceToRight); |
| |
| } else if (rect.left < screenLeft && rect.right < screenRight) { |
| // need to move right to get it in view: move right just enough so that |
| // entire rectangle is in view (or at least the first screen |
| // size chunk of it). |
| |
| if (rect.width() > width) { |
| // screen size chunk |
| scrollXDelta -= (screenRight - rect.right); |
| } else { |
| // entire rect at left |
| scrollXDelta -= (screenLeft - rect.left); |
| } |
| |
| // make sure we aren't scrolling any further than the left our content |
| scrollXDelta = Math.max(scrollXDelta, -getScrollX()); |
| } |
| return scrollXDelta; |
| } |
| |
| @Override |
| public void requestChildFocus(View child, View focused) { |
| if (focused != null && focused.getRevealOnFocusHint()) { |
| if (!mIsLayoutDirty) { |
| scrollToChild(focused); |
| } else { |
| // The child may not be laid out yet, we can't compute the scroll yet |
| mChildToScrollTo = focused; |
| } |
| } |
| super.requestChildFocus(child, focused); |
| } |
| |
| |
| /** |
| * When looking for focus in children of a scroll view, need to be a little |
| * more careful not to give focus to something that is scrolled off screen. |
| * |
| * This is more expensive than the default {@link android.view.ViewGroup} |
| * implementation, otherwise this behavior might have been made the default. |
| */ |
| @Override |
| protected boolean onRequestFocusInDescendants(int direction, |
| Rect previouslyFocusedRect) { |
| |
| // convert from forward / backward notation to up / down / left / right |
| // (ugh). |
| if (direction == View.FOCUS_FORWARD) { |
| direction = View.FOCUS_RIGHT; |
| } else if (direction == View.FOCUS_BACKWARD) { |
| direction = View.FOCUS_LEFT; |
| } |
| |
| final View nextFocus = previouslyFocusedRect == null ? |
| FocusFinder.getInstance().findNextFocus(this, null, direction) : |
| FocusFinder.getInstance().findNextFocusFromRect(this, |
| previouslyFocusedRect, direction); |
| |
| if (nextFocus == null) { |
| return false; |
| } |
| |
| if (isOffScreen(nextFocus)) { |
| return false; |
| } |
| |
| return nextFocus.requestFocus(direction, previouslyFocusedRect); |
| } |
| |
| @Override |
| public boolean requestChildRectangleOnScreen(View child, Rect rectangle, |
| boolean immediate) { |
| // offset into coordinate space of this scroll view |
| rectangle.offset(child.getLeft() - child.getScrollX(), |
| child.getTop() - child.getScrollY()); |
| |
| return scrollToChildRect(rectangle, immediate); |
| } |
| |
| @Override |
| public void requestLayout() { |
| mIsLayoutDirty = true; |
| super.requestLayout(); |
| } |
| |
| @Override |
| protected void onLayout(boolean changed, int l, int t, int r, int b) { |
| int childWidth = 0; |
| int childMargins = 0; |
| |
| if (getChildCount() > 0) { |
| childWidth = getChildAt(0).getMeasuredWidth(); |
| LayoutParams childParams = (LayoutParams) getChildAt(0).getLayoutParams(); |
| childMargins = childParams.leftMargin + childParams.rightMargin; |
| } |
| |
| final int available = r - l - getPaddingLeftWithForeground() - |
| getPaddingRightWithForeground() - childMargins; |
| |
| final boolean forceLeftGravity = (childWidth > available); |
| |
| layoutChildren(l, t, r, b, forceLeftGravity); |
| |
| mIsLayoutDirty = false; |
| // Give a child focus if it needs it |
| if (mChildToScrollTo != null && isViewDescendantOf(mChildToScrollTo, this)) { |
| scrollToChild(mChildToScrollTo); |
| } |
| mChildToScrollTo = null; |
| |
| if (!isLaidOut()) { |
| final int scrollRange = Math.max(0, |
| childWidth - (r - l - mPaddingLeft - mPaddingRight)); |
| if (mSavedState != null) { |
| mScrollX = isLayoutRtl() |
| ? scrollRange - mSavedState.scrollOffsetFromStart |
| : mSavedState.scrollOffsetFromStart; |
| mSavedState = null; |
| } else { |
| if (isLayoutRtl()) { |
| mScrollX = scrollRange - mScrollX; |
| } // mScrollX default value is "0" for LTR |
| } |
| // Don't forget to clamp |
| if (mScrollX > scrollRange) { |
| mScrollX = scrollRange; |
| } else if (mScrollX < 0) { |
| mScrollX = 0; |
| } |
| } |
| |
| // Calling this with the present values causes it to re-claim them |
| scrollTo(mScrollX, mScrollY); |
| } |
| |
| @Override |
| protected void onSizeChanged(int w, int h, int oldw, int oldh) { |
| super.onSizeChanged(w, h, oldw, oldh); |
| |
| View currentFocused = findFocus(); |
| if (null == currentFocused || this == currentFocused) |
| return; |
| |
| final int maxJump = mRight - mLeft; |
| |
| if (isWithinDeltaOfScreen(currentFocused, maxJump)) { |
| currentFocused.getDrawingRect(mTempRect); |
| offsetDescendantRectToMyCoords(currentFocused, mTempRect); |
| int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); |
| doScrollX(scrollDelta); |
| } |
| } |
| |
| /** |
| * Return true if child is a descendant of parent, (or equal to the parent). |
| */ |
| private static boolean isViewDescendantOf(View child, View parent) { |
| if (child == parent) { |
| return true; |
| } |
| |
| final ViewParent theParent = child.getParent(); |
| return (theParent instanceof ViewGroup) && isViewDescendantOf((View) theParent, parent); |
| } |
| |
| /** |
| * Fling the scroll view |
| * |
| * @param velocityX The initial velocity in the X direction. Positive |
| * numbers mean that the finger/cursor is moving down the screen, |
| * which means we want to scroll towards the left. |
| */ |
| public void fling(int velocityX) { |
| if (getChildCount() > 0) { |
| int width = getWidth() - mPaddingRight - mPaddingLeft; |
| int right = getChildAt(0).getRight() - mPaddingLeft; |
| |
| int maxScroll = Math.max(0, right - width); |
| |
| boolean shouldFling = false; |
| if (mScrollX == 0 && !mEdgeGlowLeft.isFinished()) { |
| if (shouldAbsorb(mEdgeGlowLeft, -velocityX)) { |
| mEdgeGlowLeft.onAbsorb(-velocityX); |
| } else { |
| shouldFling = true; |
| } |
| } else if (mScrollX == maxScroll && !mEdgeGlowRight.isFinished()) { |
| if (shouldAbsorb(mEdgeGlowRight, velocityX)) { |
| mEdgeGlowRight.onAbsorb(velocityX); |
| } else { |
| shouldFling = true; |
| } |
| } else { |
| shouldFling = true; |
| } |
| if (shouldFling) { |
| mScroller.fling(mScrollX, mScrollY, velocityX, 0, 0, |
| maxScroll, 0, 0, width / 2, 0); |
| |
| final boolean movingRight = velocityX > 0; |
| |
| View currentFocused = findFocus(); |
| View newFocused = findFocusableViewInMyBounds(movingRight, |
| mScroller.getFinalX(), currentFocused); |
| |
| if (newFocused == null) { |
| newFocused = this; |
| } |
| |
| if (newFocused != currentFocused) { |
| newFocused.requestFocus(movingRight ? View.FOCUS_RIGHT : View.FOCUS_LEFT); |
| } |
| } |
| |
| postInvalidateOnAnimation(); |
| } |
| } |
| |
| /** |
| * Returns true if edgeEffect should call onAbsorb() with veclocity or false if it should |
| * animate with a fling. It will animate with a fling if the velocity will remove the |
| * EdgeEffect through its normal operation. |
| * |
| * @param edgeEffect The EdgeEffect that might absorb the velocity. |
| * @param velocity The velocity of the fling motion |
| * @return true if the velocity should be absorbed or false if it should be flung. |
| */ |
| private boolean shouldAbsorb(EdgeEffect edgeEffect, int velocity) { |
| if (velocity > 0) { |
| return true; |
| } |
| float distance = edgeEffect.getDistance() * getWidth(); |
| |
| // This is flinging without the spring, so let's see if it will fling past the overscroll |
| float flingDistance = (float) mScroller.getSplineFlingDistance(-velocity); |
| |
| return flingDistance < distance; |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>This version also clamps the scrolling to the bounds of our child. |
| */ |
| @Override |
| public void scrollTo(int x, int y) { |
| // we rely on the fact the View.scrollBy calls scrollTo. |
| if (getChildCount() > 0) { |
| View child = getChildAt(0); |
| x = clamp(x, getWidth() - mPaddingRight - mPaddingLeft, child.getWidth()); |
| y = clamp(y, getHeight() - mPaddingBottom - mPaddingTop, child.getHeight()); |
| if (x != mScrollX || y != mScrollY) { |
| super.scrollTo(x, y); |
| } |
| } |
| } |
| |
| private boolean shouldDisplayEdgeEffects() { |
| return getOverScrollMode() != OVER_SCROLL_NEVER; |
| } |
| |
| @SuppressWarnings({"SuspiciousNameCombination"}) |
| @Override |
| public void draw(Canvas canvas) { |
| super.draw(canvas); |
| if (shouldDisplayEdgeEffects()) { |
| final int scrollX = mScrollX; |
| if (!mEdgeGlowLeft.isFinished()) { |
| final int restoreCount = canvas.save(); |
| final int height = getHeight() - mPaddingTop - mPaddingBottom; |
| |
| canvas.rotate(270); |
| canvas.translate(-height + mPaddingTop, Math.min(0, scrollX)); |
| mEdgeGlowLeft.setSize(height, getWidth()); |
| if (mEdgeGlowLeft.draw(canvas)) { |
| postInvalidateOnAnimation(); |
| } |
| canvas.restoreToCount(restoreCount); |
| } |
| if (!mEdgeGlowRight.isFinished()) { |
| final int restoreCount = canvas.save(); |
| final int width = getWidth(); |
| final int height = getHeight() - mPaddingTop - mPaddingBottom; |
| |
| canvas.rotate(90); |
| canvas.translate(-mPaddingTop, |
| -(Math.max(getScrollRange(), scrollX) + width)); |
| mEdgeGlowRight.setSize(height, width); |
| if (mEdgeGlowRight.draw(canvas)) { |
| postInvalidateOnAnimation(); |
| } |
| canvas.restoreToCount(restoreCount); |
| } |
| } |
| } |
| |
| private static int clamp(int n, int my, int child) { |
| if (my >= child || n < 0) { |
| return 0; |
| } |
| if ((my + n) > child) { |
| return child - my; |
| } |
| return n; |
| } |
| |
| @Override |
| protected void onRestoreInstanceState(Parcelable state) { |
| if (mContext.getApplicationInfo().targetSdkVersion <= Build.VERSION_CODES.JELLY_BEAN_MR2) { |
| // Some old apps reused IDs in ways they shouldn't have. |
| // Don't break them, but they don't get scroll state restoration. |
| super.onRestoreInstanceState(state); |
| return; |
| } |
| SavedState ss = (SavedState) state; |
| super.onRestoreInstanceState(ss.getSuperState()); |
| mSavedState = ss; |
| requestLayout(); |
| } |
| |
| @Override |
| protected Parcelable onSaveInstanceState() { |
| if (mContext.getApplicationInfo().targetSdkVersion <= Build.VERSION_CODES.JELLY_BEAN_MR2) { |
| // Some old apps reused IDs in ways they shouldn't have. |
| // Don't break them, but they don't get scroll state restoration. |
| return super.onSaveInstanceState(); |
| } |
| Parcelable superState = super.onSaveInstanceState(); |
| SavedState ss = new SavedState(superState); |
| ss.scrollOffsetFromStart = isLayoutRtl() ? -mScrollX : mScrollX; |
| return ss; |
| } |
| |
| /** @hide */ |
| @Override |
| protected void encodeProperties(@NonNull ViewHierarchyEncoder encoder) { |
| super.encodeProperties(encoder); |
| encoder.addProperty("layout:fillViewPort", mFillViewport); |
| } |
| |
| static class SavedState extends BaseSavedState { |
| public int scrollOffsetFromStart; |
| |
| SavedState(Parcelable superState) { |
| super(superState); |
| } |
| |
| public SavedState(Parcel source) { |
| super(source); |
| scrollOffsetFromStart = source.readInt(); |
| } |
| |
| @Override |
| public void writeToParcel(Parcel dest, int flags) { |
| super.writeToParcel(dest, flags); |
| dest.writeInt(scrollOffsetFromStart); |
| } |
| |
| @Override |
| public String toString() { |
| return "HorizontalScrollView.SavedState{" |
| + Integer.toHexString(System.identityHashCode(this)) |
| + " scrollPosition=" + scrollOffsetFromStart |
| + "}"; |
| } |
| |
| public static final @android.annotation.NonNull Parcelable.Creator<SavedState> CREATOR |
| = new Parcelable.Creator<SavedState>() { |
| public SavedState createFromParcel(Parcel in) { |
| return new SavedState(in); |
| } |
| |
| public SavedState[] newArray(int size) { |
| return new SavedState[size]; |
| } |
| }; |
| } |
| } |
