src/com/android/launcher3/dragndrop/DragLayer.java - LeafOS-Project/android_packages_apps_Launcher3 - Gitiles


 /*
  * Copyright (C) 2008 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 com.android.launcher3.dragndrop;

 import static com.android.launcher3.anim.Interpolators.DEACCEL_1_5;
 import static com.android.launcher3.compat.AccessibilityManagerCompat.sendCustomAccessibilityEvent;

 import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.TimeInterpolator;
 import android.animation.ValueAnimator;
 import android.animation.ValueAnimator.AnimatorUpdateListener;
 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.Canvas;
 import android.graphics.Rect;
 import android.util.AttributeSet;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.accessibility.AccessibilityEvent;
 import android.view.accessibility.AccessibilityManager;
 import android.view.animation.Interpolator;

 import com.android.launcher3.AbstractFloatingView;
 import com.android.launcher3.CellLayout;
 import com.android.launcher3.DropTargetBar;
 import com.android.launcher3.Launcher;
 import com.android.launcher3.LauncherRootView;
 import com.android.launcher3.R;
 import com.android.launcher3.ShortcutAndWidgetContainer;
 import com.android.launcher3.Workspace;
 import com.android.launcher3.folder.Folder;
 import com.android.launcher3.graphics.OverviewScrim;
 import com.android.launcher3.graphics.SysUiScrim;
 import com.android.launcher3.graphics.WorkspaceDragScrim;
 import com.android.launcher3.keyboard.ViewGroupFocusHelper;
 import com.android.launcher3.util.Thunk;
 import com.android.launcher3.views.BaseDragLayer;

 import java.util.ArrayList;

 /**
  * A ViewGroup that coordinates dragging across its descendants
  */
 public class DragLayer extends BaseDragLayer<Launcher> {

     public static final int ALPHA_INDEX_OVERLAY = 0;
     public static final int ALPHA_INDEX_LAUNCHER_LOAD = 1;
     public static final int ALPHA_INDEX_TRANSITIONS = 2;
     private static final int ALPHA_CHANNEL_COUNT = 3;

     public static final int ANIMATION_END_DISAPPEAR = 0;
     public static final int ANIMATION_END_REMAIN_VISIBLE = 2;

     private DragController mDragController;

     // Variables relating to animation of views after drop
     private ValueAnimator mDropAnim = null;

     @Thunk DragView mDropView = null;
     @Thunk int mAnchorViewInitialScrollX = 0;
     @Thunk View mAnchorView = null;

     private boolean mHoverPointClosesFolder = false;

     private int mTopViewIndex;
     private int mChildCountOnLastUpdate = -1;

     // Related to adjacent page hints
     private final ViewGroupFocusHelper mFocusIndicatorHelper;
     private final OverviewScrim mOverviewScrim;
     private WorkspaceDragScrim mWorkspaceDragScrim;
     private SysUiScrim mSysUiScrim;
     private LauncherRootView mRootView;

     /**
      * Used to create a new DragLayer from XML.
      *
      * @param context The application's context.
      * @param attrs The attributes set containing the Workspace's customization values.
      */
     public DragLayer(Context context, AttributeSet attrs) {
         super(context, attrs, ALPHA_CHANNEL_COUNT);

         // Disable multitouch across the workspace/all apps/customize tray
         setMotionEventSplittingEnabled(false);
         setChildrenDrawingOrderEnabled(true);

         mFocusIndicatorHelper = new ViewGroupFocusHelper(this);
         mOverviewScrim = new OverviewScrim(this);
     }

     public void setup(DragController dragController, Workspace workspace) {
         mDragController = dragController;
         recreateControllers();

         mWorkspaceDragScrim = new WorkspaceDragScrim((this));
         mWorkspaceDragScrim.setWorkspace(workspace);

         // We delegate drawing of the workspace scrim to LauncherRootView (one level up), so as
         // to avoid artifacts when translating the entire drag layer in the -1 transition.
         mRootView = (LauncherRootView) getParent();
         mSysUiScrim = new SysUiScrim(mRootView);
         mRootView.setSysUiScrim(mSysUiScrim);


     }

     @Override
     public void recreateControllers() {
         mControllers = mActivity.createTouchControllers();
     }

     public ViewGroupFocusHelper getFocusIndicatorHelper() {
         return mFocusIndicatorHelper;
     }

     @Override
     public boolean dispatchKeyEvent(KeyEvent event) {
         return mDragController.dispatchKeyEvent(event) || super.dispatchKeyEvent(event);
     }

     private boolean isEventOverAccessibleDropTargetBar(MotionEvent ev) {
         return isInAccessibleDrag() && isEventOverView(mActivity.getDropTargetBar(), ev);
     }

     @Override
     public boolean onInterceptHoverEvent(MotionEvent ev) {
         if (mActivity == null || mActivity.getWorkspace() == null) {
             return false;
         }
         AbstractFloatingView topView = AbstractFloatingView.getTopOpenView(mActivity);
         if (!(topView instanceof Folder)) {
             return false;
         } else {
             AccessibilityManager accessibilityManager = (AccessibilityManager)
                     getContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
             if (accessibilityManager.isTouchExplorationEnabled()) {
                 Folder currentFolder = (Folder) topView;
                 final int action = ev.getAction();
                 boolean isOverFolderOrSearchBar;
                 switch (action) {
                     case MotionEvent.ACTION_HOVER_ENTER:
                         isOverFolderOrSearchBar = isEventOverView(topView, ev) ||
                                 isEventOverAccessibleDropTargetBar(ev);
                         if (!isOverFolderOrSearchBar) {
                             sendTapOutsideFolderAccessibilityEvent(currentFolder.isEditingName());
                             mHoverPointClosesFolder = true;
                             return true;
                         }
                         mHoverPointClosesFolder = false;
                         break;
                     case MotionEvent.ACTION_HOVER_MOVE:
                         isOverFolderOrSearchBar = isEventOverView(topView, ev) ||
                                 isEventOverAccessibleDropTargetBar(ev);
                         if (!isOverFolderOrSearchBar && !mHoverPointClosesFolder) {
                             sendTapOutsideFolderAccessibilityEvent(currentFolder.isEditingName());
                             mHoverPointClosesFolder = true;
                             return true;
                         } else if (!isOverFolderOrSearchBar) {
                             return true;
                         }
                         mHoverPointClosesFolder = false;
                 }
             }
         }
         return false;
     }

     private void sendTapOutsideFolderAccessibilityEvent(boolean isEditingName) {
         int stringId = isEditingName ? R.string.folder_tap_to_rename : R.string.folder_tap_to_close;
         sendCustomAccessibilityEvent(
                 this, AccessibilityEvent.TYPE_VIEW_FOCUSED, getContext().getString(stringId));
     }

     @Override
     public boolean onHoverEvent(MotionEvent ev) {
         // If we've received this, we've already done the necessary handling
         // in onInterceptHoverEvent. Return true to consume the event.
         return false;
     }


     private boolean isInAccessibleDrag() {
         return mActivity.getAccessibilityDelegate().isInAccessibleDrag();
     }

     @Override
     public boolean onRequestSendAccessibilityEvent(View child, AccessibilityEvent event) {
         if (isInAccessibleDrag() && child instanceof DropTargetBar) {
             return true;
         }
         return super.onRequestSendAccessibilityEvent(child, event);
     }

     @Override
     public void addChildrenForAccessibility(ArrayList<View> childrenForAccessibility) {
         View topView = AbstractFloatingView.getTopOpenViewWithType(mActivity,
                 AbstractFloatingView.TYPE_ACCESSIBLE);
         if (topView != null) {
             addAccessibleChildToList(topView, childrenForAccessibility);
             if (isInAccessibleDrag()) {
                 addAccessibleChildToList(mActivity.getDropTargetBar(), childrenForAccessibility);
             }
         } else {
             super.addChildrenForAccessibility(childrenForAccessibility);
         }
     }

     @Override
     public boolean dispatchTouchEvent(MotionEvent ev) {
         ev.offsetLocation(getTranslationX(), 0);
         try {
             return super.dispatchTouchEvent(ev);
         } finally {
             ev.offsetLocation(-getTranslationX(), 0);
         }
     }

     public void animateViewIntoPosition(DragView dragView, final int[] pos, float alpha,
             float scaleX, float scaleY, int animationEndStyle, Runnable onFinishRunnable,
             int duration) {
         Rect r = new Rect();
         getViewRectRelativeToSelf(dragView, r);
         final int fromX = r.left;
         final int fromY = r.top;

         animateViewIntoPosition(dragView, fromX, fromY, pos[0], pos[1], alpha, 1, 1, scaleX, scaleY,
                 onFinishRunnable, animationEndStyle, duration, null);
     }

     public void animateViewIntoPosition(DragView dragView, final View child, View anchorView) {
         animateViewIntoPosition(dragView, child, -1, anchorView);
     }

     public void animateViewIntoPosition(DragView dragView, final View child, int duration,
             View anchorView) {

         ShortcutAndWidgetContainer parentChildren = (ShortcutAndWidgetContainer) child.getParent();
         CellLayout.LayoutParams lp =  (CellLayout.LayoutParams) child.getLayoutParams();
         parentChildren.measureChild(child);
         parentChildren.layoutChild(child);

         Rect dragViewBounds = new Rect();
         getViewRectRelativeToSelf(dragView, dragViewBounds);
         final int fromX = dragViewBounds.left;
         final int fromY = dragViewBounds.top;

         float coord[] = new float[2];
         float childScale = child.getScaleX();

         coord[0] = lp.x + (child.getMeasuredWidth() * (1 - childScale) / 2);
         coord[1] = lp.y + (child.getMeasuredHeight() * (1 - childScale) / 2);

         // Since the child hasn't necessarily been laid out, we force the lp to be updated with
         // the correct coordinates (above) and use these to determine the final location
         float scale = getDescendantCoordRelativeToSelf((View) child.getParent(), coord);

         // We need to account for the scale of the child itself, as the above only accounts for
         // for the scale in parents.
         scale *= childScale;
         int toX = Math.round(coord[0]);
         int toY = Math.round(coord[1]);

         float toScale = scale;

         if (child instanceof DraggableView) {
             // This code is fairly subtle. Please verify drag and drop is pixel-perfect in a number
             // of scenarios before modifying (from all apps, from workspace, different grid-sizes,
             // shortcuts from in and out of Launcher etc).
             DraggableView d = (DraggableView) child;
             Rect destRect = new Rect();
             d.getWorkspaceVisualDragBounds(destRect);

             // In most cases this additional scale factor should be a no-op (1). It mainly accounts
             // for alternate grids where the source and destination icon sizes are different
             toScale *= ((1f * destRect.width())
                     / (dragView.getMeasuredWidth() - dragView.getBlurSizeOutline()));

             // This accounts for the offset of the DragView created by scaling it about its
             // center as it animates into place.
             float scaleShiftX = dragView.getMeasuredWidth() * (1 - toScale) / 2;
             float scaleShiftY = dragView.getMeasuredHeight() * (1 - toScale) / 2;

             toX += scale * destRect.left - toScale * dragView.getBlurSizeOutline() / 2 - scaleShiftX;
             toY += scale * destRect.top - toScale * dragView.getBlurSizeOutline() / 2 - scaleShiftY;
         }

         child.setVisibility(INVISIBLE);
         Runnable onCompleteRunnable = () -> child.setVisibility(VISIBLE);
         animateViewIntoPosition(dragView, fromX, fromY, toX, toY, 1, 1, 1, toScale, toScale,
                 onCompleteRunnable, ANIMATION_END_DISAPPEAR, duration, anchorView);
     }

     public void animateViewIntoPosition(final DragView view, final int fromX, final int fromY,
             final int toX, final int toY, float finalAlpha, float initScaleX, float initScaleY,
             float finalScaleX, float finalScaleY, Runnable onCompleteRunnable,
             int animationEndStyle, int duration, View anchorView) {
         Rect from = new Rect(fromX, fromY, fromX +
                 view.getMeasuredWidth(), fromY + view.getMeasuredHeight());
         Rect to = new Rect(toX, toY, toX + view.getMeasuredWidth(), toY + view.getMeasuredHeight());
         animateView(view, from, to, finalAlpha, initScaleX, initScaleY, finalScaleX, finalScaleY, duration,
                 null, null, onCompleteRunnable, animationEndStyle, anchorView);
     }

     /**
      * This method animates a view at the end of a drag and drop animation.
      *
      * @param view The view to be animated. This view is drawn directly into DragLayer, and so
      *        doesn't need to be a child of DragLayer.
      * @param from The initial location of the view. Only the left and top parameters are used.
      * @param to The final location of the view. Only the left and top parameters are used. This
      *        location doesn't account for scaling, and so should be centered about the desired
      *        final location (including scaling).
      * @param finalAlpha The final alpha of the view, in case we want it to fade as it animates.
      * @param finalScaleX The final scale of the view. The view is scaled about its center.
      * @param finalScaleY The final scale of the view. The view is scaled about its center.
      * @param duration The duration of the animation.
      * @param motionInterpolator The interpolator to use for the location of the view.
      * @param alphaInterpolator The interpolator to use for the alpha of the view.
      * @param onCompleteRunnable Optional runnable to run on animation completion.
      * @param animationEndStyle Whether or not to fade out the view once the animation completes.
      *        {@link #ANIMATION_END_DISAPPEAR} or {@link #ANIMATION_END_REMAIN_VISIBLE}.
      * @param anchorView If not null, this represents the view which the animated view stays
      *        anchored to in case scrolling is currently taking place. Note: currently this is
      *        only used for the X dimension for the case of the workspace.
      */
     public void animateView(final DragView view, final Rect from, final Rect to,
             final float finalAlpha, final float initScaleX, final float initScaleY,
             final float finalScaleX, final float finalScaleY, int duration,
             final Interpolator motionInterpolator, final Interpolator alphaInterpolator,
             final Runnable onCompleteRunnable, final int animationEndStyle, View anchorView) {

         // Calculate the duration of the animation based on the object's distance
         final float dist = (float) Math.hypot(to.left - from.left, to.top - from.top);
         final Resources res = getResources();
         final float maxDist = (float) res.getInteger(R.integer.config_dropAnimMaxDist);

         // If duration < 0, this is a cue to compute the duration based on the distance
         if (duration < 0) {
             duration = res.getInteger(R.integer.config_dropAnimMaxDuration);
             if (dist < maxDist) {
                 duration *= DEACCEL_1_5.getInterpolation(dist / maxDist);
             }
             duration = Math.max(duration, res.getInteger(R.integer.config_dropAnimMinDuration));
         }

         // Fall back to cubic ease out interpolator for the animation if none is specified
         TimeInterpolator interpolator = null;
         if (alphaInterpolator == null || motionInterpolator == null) {
             interpolator = DEACCEL_1_5;
         }

         // Animate the view
         final float initAlpha = view.getAlpha();
         final float dropViewScale = view.getScaleX();
         AnimatorUpdateListener updateCb = new AnimatorUpdateListener() {
             @Override
             public void onAnimationUpdate(ValueAnimator animation) {
                 final float percent = (Float) animation.getAnimatedValue();
                 final int width = view.getMeasuredWidth();
                 final int height = view.getMeasuredHeight();

                 float alphaPercent = alphaInterpolator == null ? percent :
                         alphaInterpolator.getInterpolation(percent);
                 float motionPercent = motionInterpolator == null ? percent :
                         motionInterpolator.getInterpolation(percent);

                 float initialScaleX = initScaleX * dropViewScale;
                 float initialScaleY = initScaleY * dropViewScale;
                 float scaleX = finalScaleX * percent + initialScaleX * (1 - percent);
                 float scaleY = finalScaleY * percent + initialScaleY * (1 - percent);
                 float alpha = finalAlpha * alphaPercent + initAlpha * (1 - alphaPercent);

                 float fromLeft = from.left + (initialScaleX - 1f) * width / 2;
                 float fromTop = from.top + (initialScaleY - 1f) * height / 2;

                 int x = (int) (fromLeft + Math.round(((to.left - fromLeft) * motionPercent)));
                 int y = (int) (fromTop + Math.round(((to.top - fromTop) * motionPercent)));

                 int anchorAdjust = mAnchorView == null ? 0 : (int) (mAnchorView.getScaleX() *
                     (mAnchorViewInitialScrollX - mAnchorView.getScrollX()));

                 int xPos = x - mDropView.getScrollX() + anchorAdjust;
                 int yPos = y - mDropView.getScrollY();

                 mDropView.setTranslationX(xPos);
                 mDropView.setTranslationY(yPos);
                 mDropView.setScaleX(scaleX);
                 mDropView.setScaleY(scaleY);
                 mDropView.setAlpha(alpha);
             }
         };
         animateView(view, updateCb, duration, interpolator, onCompleteRunnable, animationEndStyle,
                 anchorView);
     }

     public void animateView(final DragView view, AnimatorUpdateListener updateCb, int duration,
             TimeInterpolator interpolator, final Runnable onCompleteRunnable,
             final int animationEndStyle, View anchorView) {
         // Clean up the previous animations
         if (mDropAnim != null) mDropAnim.cancel();

         // Show the drop view if it was previously hidden
         mDropView = view;
         mDropView.cancelAnimation();
         mDropView.requestLayout();

         // Set the anchor view if the page is scrolling
         if (anchorView != null) {
             mAnchorViewInitialScrollX = anchorView.getScrollX();
         }
         mAnchorView = anchorView;

         // Create and start the animation
         mDropAnim = new ValueAnimator();
         mDropAnim.setInterpolator(interpolator);
         mDropAnim.setDuration(duration);
         mDropAnim.setFloatValues(0f, 1f);
         mDropAnim.addUpdateListener(updateCb);
         mDropAnim.addListener(new AnimatorListenerAdapter() {
             public void onAnimationEnd(Animator animation) {
                 if (onCompleteRunnable != null) {
                     onCompleteRunnable.run();
                 }
                 switch (animationEndStyle) {
                 case ANIMATION_END_DISAPPEAR:
                     clearAnimatedView();
                     break;
                 case ANIMATION_END_REMAIN_VISIBLE:
                     break;
                 }
                 mDropAnim = null;
             }
         });
         mDropAnim.start();
     }

     public void clearAnimatedView() {
         if (mDropAnim != null) {
             mDropAnim.cancel();
         }
         mDropAnim = null;
         if (mDropView != null) {
             mDragController.onDeferredEndDrag(mDropView);
         }
         mDropView = null;
         invalidate();
     }

     public View getAnimatedView() {
         return mDropView;
     }

     @Override
     public void onViewAdded(View child) {
         super.onViewAdded(child);
         updateChildIndices();
         mActivity.onDragLayerHierarchyChanged();
     }

     @Override
     public void onViewRemoved(View child) {
         super.onViewRemoved(child);
         updateChildIndices();
         mActivity.onDragLayerHierarchyChanged();
     }

     @Override
     public void bringChildToFront(View child) {
         super.bringChildToFront(child);
         updateChildIndices();
     }

     private void updateChildIndices() {
         mTopViewIndex = -1;
         int childCount = getChildCount();
         for (int i = 0; i < childCount; i++) {
             if (getChildAt(i) instanceof DragView) {
                 mTopViewIndex = i;
             }
         }
         mChildCountOnLastUpdate = childCount;
     }

     @Override
     protected int getChildDrawingOrder(int childCount, int i) {
         if (mChildCountOnLastUpdate != childCount) {
             // between platform versions 17 and 18, behavior for onChildViewRemoved / Added changed.
             // Pre-18, the child was not added / removed by the time of those callbacks. We need to
             // force update our representation of things here to avoid crashing on pre-18 devices
             // in certain instances.
             updateChildIndices();
         }

         // i represents the current draw iteration
         if (mTopViewIndex == -1) {
             // in general we do nothing
             return i;
         } else if (i == childCount - 1) {
             // if we have a top index, we return it when drawing last item (highest z-order)
             return mTopViewIndex;
         } else if (i < mTopViewIndex) {
             return i;
         } else {
             // for indexes greater than the top index, we fetch one item above to shift for the
             // displacement of the top index
             return i + 1;
         }
     }

     @Override
     protected void dispatchDraw(Canvas canvas) {
         // Draw the background below children.
         mWorkspaceDragScrim.draw(canvas);
         mOverviewScrim.updateCurrentScrimmedView(this);
         mFocusIndicatorHelper.draw(canvas);
         super.dispatchDraw(canvas);
         if (mOverviewScrim.getScrimmedView() == null) {
             mOverviewScrim.draw(canvas);
         }
     }

     @Override
     protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
         if (child == mOverviewScrim.getScrimmedView()) {
             mOverviewScrim.draw(canvas);
         }
         return super.drawChild(canvas, child, drawingTime);
     }

     @Override
     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
         super.onSizeChanged(w, h, oldw, oldh);
         mSysUiScrim.setSize(w, h);
     }

     @Override
     public void setInsets(Rect insets) {
         super.setInsets(insets);
         mSysUiScrim.onInsetsChanged(insets, mAllowSysuiScrims);
         mOverviewScrim.onInsetsChanged(insets);
     }

     public WorkspaceDragScrim getWorkspaceDragScrim() {
         return mWorkspaceDragScrim;
     }

     public SysUiScrim getSysUiScrim() {
         return mSysUiScrim;
     }

     public OverviewScrim getOverviewScrim() {
         return mOverviewScrim;
     }
 }

	/*
	* Copyright (C) 2008 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 com.android.launcher3.dragndrop;

	import static com.android.launcher3.anim.Interpolators.DEACCEL_1_5;
	import static com.android.launcher3.compat.AccessibilityManagerCompat.sendCustomAccessibilityEvent;

	import android.animation.Animator;
	import android.animation.AnimatorListenerAdapter;
	import android.animation.TimeInterpolator;
	import android.animation.ValueAnimator;
	import android.animation.ValueAnimator.AnimatorUpdateListener;
	import android.content.Context;
	import android.content.res.Resources;
	import android.graphics.Canvas;
	import android.graphics.Rect;
	import android.util.AttributeSet;
	import android.view.KeyEvent;
	import android.view.MotionEvent;
	import android.view.View;
	import android.view.accessibility.AccessibilityEvent;
	import android.view.accessibility.AccessibilityManager;
	import android.view.animation.Interpolator;

	import com.android.launcher3.AbstractFloatingView;
	import com.android.launcher3.CellLayout;
	import com.android.launcher3.DropTargetBar;
	import com.android.launcher3.Launcher;
	import com.android.launcher3.LauncherRootView;
	import com.android.launcher3.R;
	import com.android.launcher3.ShortcutAndWidgetContainer;
	import com.android.launcher3.Workspace;
	import com.android.launcher3.folder.Folder;
	import com.android.launcher3.graphics.OverviewScrim;
	import com.android.launcher3.graphics.SysUiScrim;
	import com.android.launcher3.graphics.WorkspaceDragScrim;
	import com.android.launcher3.keyboard.ViewGroupFocusHelper;
	import com.android.launcher3.util.Thunk;
	import com.android.launcher3.views.BaseDragLayer;

	import java.util.ArrayList;

	/**
	* A ViewGroup that coordinates dragging across its descendants
	*/
	public class DragLayer extends BaseDragLayer<Launcher> {

	public static final int ALPHA_INDEX_OVERLAY = 0;
	public static final int ALPHA_INDEX_LAUNCHER_LOAD = 1;
	public static final int ALPHA_INDEX_TRANSITIONS = 2;
	private static final int ALPHA_CHANNEL_COUNT = 3;

	public static final int ANIMATION_END_DISAPPEAR = 0;
	public static final int ANIMATION_END_REMAIN_VISIBLE = 2;

	private DragController mDragController;

	// Variables relating to animation of views after drop
	private ValueAnimator mDropAnim = null;

	@Thunk DragView mDropView = null;
	@Thunk int mAnchorViewInitialScrollX = 0;
	@Thunk View mAnchorView = null;

	private boolean mHoverPointClosesFolder = false;

	private int mTopViewIndex;
	private int mChildCountOnLastUpdate = -1;

	// Related to adjacent page hints
	private final ViewGroupFocusHelper mFocusIndicatorHelper;
	private final OverviewScrim mOverviewScrim;
	private WorkspaceDragScrim mWorkspaceDragScrim;
	private SysUiScrim mSysUiScrim;
	private LauncherRootView mRootView;

	/**
	* Used to create a new DragLayer from XML.
	*
	* @param context The application's context.
	* @param attrs The attributes set containing the Workspace's customization values.
	*/
	public DragLayer(Context context, AttributeSet attrs) {
	super(context, attrs, ALPHA_CHANNEL_COUNT);

	// Disable multitouch across the workspace/all apps/customize tray
	setMotionEventSplittingEnabled(false);
	setChildrenDrawingOrderEnabled(true);

	mFocusIndicatorHelper = new ViewGroupFocusHelper(this);
	mOverviewScrim = new OverviewScrim(this);
	}

	public void setup(DragController dragController, Workspace workspace) {
	mDragController = dragController;
	recreateControllers();

	mWorkspaceDragScrim = new WorkspaceDragScrim((this));
	mWorkspaceDragScrim.setWorkspace(workspace);

	// We delegate drawing of the workspace scrim to LauncherRootView (one level up), so as
	// to avoid artifacts when translating the entire drag layer in the -1 transition.
	mRootView = (LauncherRootView) getParent();
	mSysUiScrim = new SysUiScrim(mRootView);
	mRootView.setSysUiScrim(mSysUiScrim);


	}

	@Override
	public void recreateControllers() {
	mControllers = mActivity.createTouchControllers();
	}

	public ViewGroupFocusHelper getFocusIndicatorHelper() {
	return mFocusIndicatorHelper;
	}

	@Override
	public boolean dispatchKeyEvent(KeyEvent event) {
	return mDragController.dispatchKeyEvent(event) \|\| super.dispatchKeyEvent(event);
	}

	private boolean isEventOverAccessibleDropTargetBar(MotionEvent ev) {
	return isInAccessibleDrag() && isEventOverView(mActivity.getDropTargetBar(), ev);
	}

	@Override
	public boolean onInterceptHoverEvent(MotionEvent ev) {
	if (mActivity == null \|\| mActivity.getWorkspace() == null) {
	return false;
	}
	AbstractFloatingView topView = AbstractFloatingView.getTopOpenView(mActivity);
	if (!(topView instanceof Folder)) {
	return false;
	} else {
	AccessibilityManager accessibilityManager = (AccessibilityManager)
	getContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
	if (accessibilityManager.isTouchExplorationEnabled()) {
	Folder currentFolder = (Folder) topView;
	final int action = ev.getAction();
	boolean isOverFolderOrSearchBar;
	switch (action) {
	case MotionEvent.ACTION_HOVER_ENTER:
	isOverFolderOrSearchBar = isEventOverView(topView, ev) \|\|
	isEventOverAccessibleDropTargetBar(ev);
	if (!isOverFolderOrSearchBar) {
	sendTapOutsideFolderAccessibilityEvent(currentFolder.isEditingName());
	mHoverPointClosesFolder = true;
	return true;
	}
	mHoverPointClosesFolder = false;
	break;
	case MotionEvent.ACTION_HOVER_MOVE:
	isOverFolderOrSearchBar = isEventOverView(topView, ev) \|\|
	isEventOverAccessibleDropTargetBar(ev);
	if (!isOverFolderOrSearchBar && !mHoverPointClosesFolder) {
	sendTapOutsideFolderAccessibilityEvent(currentFolder.isEditingName());
	mHoverPointClosesFolder = true;
	return true;
	} else if (!isOverFolderOrSearchBar) {
	return true;
	}
	mHoverPointClosesFolder = false;
	}
	}
	}
	return false;
	}

	private void sendTapOutsideFolderAccessibilityEvent(boolean isEditingName) {
	int stringId = isEditingName ? R.string.folder_tap_to_rename : R.string.folder_tap_to_close;
	sendCustomAccessibilityEvent(
	this, AccessibilityEvent.TYPE_VIEW_FOCUSED, getContext().getString(stringId));
	}

	@Override
	public boolean onHoverEvent(MotionEvent ev) {
	// If we've received this, we've already done the necessary handling
	// in onInterceptHoverEvent. Return true to consume the event.
	return false;
	}


	private boolean isInAccessibleDrag() {
	return mActivity.getAccessibilityDelegate().isInAccessibleDrag();
	}

	@Override
	public boolean onRequestSendAccessibilityEvent(View child, AccessibilityEvent event) {
	if (isInAccessibleDrag() && child instanceof DropTargetBar) {
	return true;
	}
	return super.onRequestSendAccessibilityEvent(child, event);
	}

	@Override
	public void addChildrenForAccessibility(ArrayList<View> childrenForAccessibility) {
	View topView = AbstractFloatingView.getTopOpenViewWithType(mActivity,
	AbstractFloatingView.TYPE_ACCESSIBLE);
	if (topView != null) {
	addAccessibleChildToList(topView, childrenForAccessibility);
	if (isInAccessibleDrag()) {
	addAccessibleChildToList(mActivity.getDropTargetBar(), childrenForAccessibility);
	}
	} else {
	super.addChildrenForAccessibility(childrenForAccessibility);
	}
	}

	@Override
	public boolean dispatchTouchEvent(MotionEvent ev) {
	ev.offsetLocation(getTranslationX(), 0);
	try {
	return super.dispatchTouchEvent(ev);
	} finally {
	ev.offsetLocation(-getTranslationX(), 0);
	}
	}

	public void animateViewIntoPosition(DragView dragView, final int[] pos, float alpha,
	float scaleX, float scaleY, int animationEndStyle, Runnable onFinishRunnable,
	int duration) {
	Rect r = new Rect();
	getViewRectRelativeToSelf(dragView, r);
	final int fromX = r.left;
	final int fromY = r.top;

	animateViewIntoPosition(dragView, fromX, fromY, pos[0], pos[1], alpha, 1, 1, scaleX, scaleY,
	onFinishRunnable, animationEndStyle, duration, null);
	}

	public void animateViewIntoPosition(DragView dragView, final View child, View anchorView) {
	animateViewIntoPosition(dragView, child, -1, anchorView);
	}

	public void animateViewIntoPosition(DragView dragView, final View child, int duration,
	View anchorView) {

	ShortcutAndWidgetContainer parentChildren = (ShortcutAndWidgetContainer) child.getParent();
	CellLayout.LayoutParams lp = (CellLayout.LayoutParams) child.getLayoutParams();
	parentChildren.measureChild(child);
	parentChildren.layoutChild(child);

	Rect dragViewBounds = new Rect();
	getViewRectRelativeToSelf(dragView, dragViewBounds);
	final int fromX = dragViewBounds.left;
	final int fromY = dragViewBounds.top;

	float coord[] = new float[2];
	float childScale = child.getScaleX();

	coord[0] = lp.x + (child.getMeasuredWidth() * (1 - childScale) / 2);
	coord[1] = lp.y + (child.getMeasuredHeight() * (1 - childScale) / 2);

	// Since the child hasn't necessarily been laid out, we force the lp to be updated with
	// the correct coordinates (above) and use these to determine the final location
	float scale = getDescendantCoordRelativeToSelf((View) child.getParent(), coord);

	// We need to account for the scale of the child itself, as the above only accounts for
	// for the scale in parents.
	scale *= childScale;
	int toX = Math.round(coord[0]);
	int toY = Math.round(coord[1]);

	float toScale = scale;

	if (child instanceof DraggableView) {
	// This code is fairly subtle. Please verify drag and drop is pixel-perfect in a number
	// of scenarios before modifying (from all apps, from workspace, different grid-sizes,
	// shortcuts from in and out of Launcher etc).
	DraggableView d = (DraggableView) child;
	Rect destRect = new Rect();
	d.getWorkspaceVisualDragBounds(destRect);

	// In most cases this additional scale factor should be a no-op (1). It mainly accounts
	// for alternate grids where the source and destination icon sizes are different
	toScale = ((1f destRect.width())
	/ (dragView.getMeasuredWidth() - dragView.getBlurSizeOutline()));

	// This accounts for the offset of the DragView created by scaling it about its
	// center as it animates into place.
	float scaleShiftX = dragView.getMeasuredWidth() * (1 - toScale) / 2;
	float scaleShiftY = dragView.getMeasuredHeight() * (1 - toScale) / 2;

	toX += scale * destRect.left - toScale * dragView.getBlurSizeOutline() / 2 - scaleShiftX;
	toY += scale * destRect.top - toScale * dragView.getBlurSizeOutline() / 2 - scaleShiftY;
	}

	child.setVisibility(INVISIBLE);
	Runnable onCompleteRunnable = () -> child.setVisibility(VISIBLE);
	animateViewIntoPosition(dragView, fromX, fromY, toX, toY, 1, 1, 1, toScale, toScale,
	onCompleteRunnable, ANIMATION_END_DISAPPEAR, duration, anchorView);
	}

	public void animateViewIntoPosition(final DragView view, final int fromX, final int fromY,
	final int toX, final int toY, float finalAlpha, float initScaleX, float initScaleY,
	float finalScaleX, float finalScaleY, Runnable onCompleteRunnable,
	int animationEndStyle, int duration, View anchorView) {
	Rect from = new Rect(fromX, fromY, fromX +
	view.getMeasuredWidth(), fromY + view.getMeasuredHeight());
	Rect to = new Rect(toX, toY, toX + view.getMeasuredWidth(), toY + view.getMeasuredHeight());
	animateView(view, from, to, finalAlpha, initScaleX, initScaleY, finalScaleX, finalScaleY, duration,
	null, null, onCompleteRunnable, animationEndStyle, anchorView);
	}

	/**
	* This method animates a view at the end of a drag and drop animation.
	*
	* @param view The view to be animated. This view is drawn directly into DragLayer, and so
	* doesn't need to be a child of DragLayer.
	* @param from The initial location of the view. Only the left and top parameters are used.
	* @param to The final location of the view. Only the left and top parameters are used. This
	* location doesn't account for scaling, and so should be centered about the desired
	* final location (including scaling).
	* @param finalAlpha The final alpha of the view, in case we want it to fade as it animates.
	* @param finalScaleX The final scale of the view. The view is scaled about its center.
	* @param finalScaleY The final scale of the view. The view is scaled about its center.
	* @param duration The duration of the animation.
	* @param motionInterpolator The interpolator to use for the location of the view.
	* @param alphaInterpolator The interpolator to use for the alpha of the view.
	* @param onCompleteRunnable Optional runnable to run on animation completion.
	* @param animationEndStyle Whether or not to fade out the view once the animation completes.
	* {@link #ANIMATION_END_DISAPPEAR} or {@link #ANIMATION_END_REMAIN_VISIBLE}.
	* @param anchorView If not null, this represents the view which the animated view stays
	* anchored to in case scrolling is currently taking place. Note: currently this is
	* only used for the X dimension for the case of the workspace.
	*/
	public void animateView(final DragView view, final Rect from, final Rect to,
	final float finalAlpha, final float initScaleX, final float initScaleY,
	final float finalScaleX, final float finalScaleY, int duration,
	final Interpolator motionInterpolator, final Interpolator alphaInterpolator,
	final Runnable onCompleteRunnable, final int animationEndStyle, View anchorView) {

	// Calculate the duration of the animation based on the object's distance
	final float dist = (float) Math.hypot(to.left - from.left, to.top - from.top);
	final Resources res = getResources();
	final float maxDist = (float) res.getInteger(R.integer.config_dropAnimMaxDist);

	// If duration < 0, this is a cue to compute the duration based on the distance
	if (duration < 0) {
	duration = res.getInteger(R.integer.config_dropAnimMaxDuration);
	if (dist < maxDist) {
	duration *= DEACCEL_1_5.getInterpolation(dist / maxDist);
	}
	duration = Math.max(duration, res.getInteger(R.integer.config_dropAnimMinDuration));
	}

	// Fall back to cubic ease out interpolator for the animation if none is specified
	TimeInterpolator interpolator = null;
	if (alphaInterpolator == null \|\| motionInterpolator == null) {
	interpolator = DEACCEL_1_5;
	}

	// Animate the view
	final float initAlpha = view.getAlpha();
	final float dropViewScale = view.getScaleX();
	AnimatorUpdateListener updateCb = new AnimatorUpdateListener() {
	@Override
	public void onAnimationUpdate(ValueAnimator animation) {
	final float percent = (Float) animation.getAnimatedValue();
	final int width = view.getMeasuredWidth();
	final int height = view.getMeasuredHeight();

	float alphaPercent = alphaInterpolator == null ? percent :
	alphaInterpolator.getInterpolation(percent);
	float motionPercent = motionInterpolator == null ? percent :
	motionInterpolator.getInterpolation(percent);

	float initialScaleX = initScaleX * dropViewScale;
	float initialScaleY = initScaleY * dropViewScale;
	float scaleX = finalScaleX * percent + initialScaleX * (1 - percent);
	float scaleY = finalScaleY * percent + initialScaleY * (1 - percent);
	float alpha = finalAlpha * alphaPercent + initAlpha * (1 - alphaPercent);

	float fromLeft = from.left + (initialScaleX - 1f) * width / 2;
	float fromTop = from.top + (initialScaleY - 1f) * height / 2;

	int x = (int) (fromLeft + Math.round(((to.left - fromLeft) * motionPercent)));
	int y = (int) (fromTop + Math.round(((to.top - fromTop) * motionPercent)));

	int anchorAdjust = mAnchorView == null ? 0 : (int) (mAnchorView.getScaleX() *
	(mAnchorViewInitialScrollX - mAnchorView.getScrollX()));

	int xPos = x - mDropView.getScrollX() + anchorAdjust;
	int yPos = y - mDropView.getScrollY();

	mDropView.setTranslationX(xPos);
	mDropView.setTranslationY(yPos);
	mDropView.setScaleX(scaleX);
	mDropView.setScaleY(scaleY);
	mDropView.setAlpha(alpha);
	}
	};
	animateView(view, updateCb, duration, interpolator, onCompleteRunnable, animationEndStyle,
	anchorView);
	}

	public void animateView(final DragView view, AnimatorUpdateListener updateCb, int duration,
	TimeInterpolator interpolator, final Runnable onCompleteRunnable,
	final int animationEndStyle, View anchorView) {
	// Clean up the previous animations
	if (mDropAnim != null) mDropAnim.cancel();

	// Show the drop view if it was previously hidden
	mDropView = view;
	mDropView.cancelAnimation();
	mDropView.requestLayout();

	// Set the anchor view if the page is scrolling
	if (anchorView != null) {
	mAnchorViewInitialScrollX = anchorView.getScrollX();
	}
	mAnchorView = anchorView;

	// Create and start the animation
	mDropAnim = new ValueAnimator();
	mDropAnim.setInterpolator(interpolator);
	mDropAnim.setDuration(duration);
	mDropAnim.setFloatValues(0f, 1f);
	mDropAnim.addUpdateListener(updateCb);
	mDropAnim.addListener(new AnimatorListenerAdapter() {
	public void onAnimationEnd(Animator animation) {
	if (onCompleteRunnable != null) {
	onCompleteRunnable.run();
	}
	switch (animationEndStyle) {
	case ANIMATION_END_DISAPPEAR:
	clearAnimatedView();
	break;
	case ANIMATION_END_REMAIN_VISIBLE:
	break;
	}
	mDropAnim = null;
	}
	});
	mDropAnim.start();
	}

	public void clearAnimatedView() {
	if (mDropAnim != null) {
	mDropAnim.cancel();
	}
	mDropAnim = null;
	if (mDropView != null) {
	mDragController.onDeferredEndDrag(mDropView);
	}
	mDropView = null;
	invalidate();
	}

	public View getAnimatedView() {
	return mDropView;
	}

	@Override
	public void onViewAdded(View child) {
	super.onViewAdded(child);
	updateChildIndices();
	mActivity.onDragLayerHierarchyChanged();
	}

	@Override
	public void onViewRemoved(View child) {
	super.onViewRemoved(child);
	updateChildIndices();
	mActivity.onDragLayerHierarchyChanged();
	}

	@Override
	public void bringChildToFront(View child) {
	super.bringChildToFront(child);
	updateChildIndices();
	}

	private void updateChildIndices() {
	mTopViewIndex = -1;
	int childCount = getChildCount();
	for (int i = 0; i < childCount; i++) {
	if (getChildAt(i) instanceof DragView) {
	mTopViewIndex = i;
	}
	}
	mChildCountOnLastUpdate = childCount;
	}

	@Override
	protected int getChildDrawingOrder(int childCount, int i) {
	if (mChildCountOnLastUpdate != childCount) {
	// between platform versions 17 and 18, behavior for onChildViewRemoved / Added changed.
	// Pre-18, the child was not added / removed by the time of those callbacks. We need to
	// force update our representation of things here to avoid crashing on pre-18 devices
	// in certain instances.
	updateChildIndices();
	}

	// i represents the current draw iteration
	if (mTopViewIndex == -1) {
	// in general we do nothing
	return i;
	} else if (i == childCount - 1) {
	// if we have a top index, we return it when drawing last item (highest z-order)
	return mTopViewIndex;
	} else if (i < mTopViewIndex) {
	return i;
	} else {
	// for indexes greater than the top index, we fetch one item above to shift for the
	// displacement of the top index
	return i + 1;
	}
	}

	@Override
	protected void dispatchDraw(Canvas canvas) {
	// Draw the background below children.
	mWorkspaceDragScrim.draw(canvas);
	mOverviewScrim.updateCurrentScrimmedView(this);
	mFocusIndicatorHelper.draw(canvas);
	super.dispatchDraw(canvas);
	if (mOverviewScrim.getScrimmedView() == null) {
	mOverviewScrim.draw(canvas);
	}
	}

	@Override
	protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
	if (child == mOverviewScrim.getScrimmedView()) {
	mOverviewScrim.draw(canvas);
	}
	return super.drawChild(canvas, child, drawingTime);
	}

	@Override
	protected void onSizeChanged(int w, int h, int oldw, int oldh) {
	super.onSizeChanged(w, h, oldw, oldh);
	mSysUiScrim.setSize(w, h);
	}

	@Override
	public void setInsets(Rect insets) {
	super.setInsets(insets);
	mSysUiScrim.onInsetsChanged(insets, mAllowSysuiScrims);
	mOverviewScrim.onInsetsChanged(insets);
	}

	public WorkspaceDragScrim getWorkspaceDragScrim() {
	return mWorkspaceDragScrim;
	}

	public SysUiScrim getSysUiScrim() {
	return mSysUiScrim;
	}

	public OverviewScrim getOverviewScrim() {
	return mOverviewScrim;
	}
	}