src/com/android/launcher3/dragndrop/DragController.java - platform/packages/apps/Launcher3 - Git at Google

 /*
  * 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.AbstractFloatingView.TYPE_DISCOVERY_BOUNCE;
 import static com.android.launcher3.LauncherAnimUtils.SPRING_LOADED_EXIT_DELAY;
 import static com.android.launcher3.LauncherState.NORMAL;
 import static com.android.launcher3.Utilities.ATLEAST_Q;
 import static com.android.launcher3.util.Executors.MAIN_EXECUTOR;

 import android.animation.ValueAnimator;
 import android.content.ComponentName;
 import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.view.DragEvent;
 import android.view.HapticFeedbackConstants;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
 import android.view.View;

 import com.android.launcher3.AbstractFloatingView;
 import com.android.launcher3.DragSource;
 import com.android.launcher3.DropTarget;
 import com.android.launcher3.Launcher;
 import com.android.launcher3.R;
 import com.android.launcher3.accessibility.DragViewStateAnnouncer;
 import com.android.launcher3.model.data.ItemInfo;
 import com.android.launcher3.model.data.WorkspaceItemInfo;
 import com.android.launcher3.util.ItemInfoMatcher;
 import com.android.launcher3.util.TouchController;

 import java.util.ArrayList;

 /**
  * Class for initiating a drag within a view or across multiple views.
  */
 public class DragController implements DragDriver.EventListener, TouchController {
     private static final boolean PROFILE_DRAWING_DURING_DRAG = false;

     /**
      * When a drag is started from a deep press, you need to drag this much farther than normal to
      * end a pre-drag. See {@link DragOptions.PreDragCondition#shouldStartDrag(double)}.
      */
     private static final int DEEP_PRESS_DISTANCE_FACTOR = 3;

     private final Launcher mLauncher;
     private final FlingToDeleteHelper mFlingToDeleteHelper;

     // temporaries to avoid gc thrash
     private final Rect mRectTemp = new Rect();
     private final int[] mCoordinatesTemp = new int[2];

     /**
      * Drag driver for the current drag/drop operation, or null if there is no active DND operation.
      * It's null during accessible drag operations.
      */
     private DragDriver mDragDriver = null;

     /** Options controlling the drag behavior. */
     private DragOptions mOptions;

     /** Coordinate for motion down event */
     private final Point mMotionDown = new Point();
     /** Coordinate for last touch event **/
     private final Point mLastTouch = new Point();

     private final Point mTmpPoint = new Point();

     private DropTarget.DragObject mDragObject;

     /** Who can receive drop events */
     private final ArrayList<DropTarget> mDropTargets = new ArrayList<>();
     private final ArrayList<DragListener> mListeners = new ArrayList<>();

     private DropTarget mLastDropTarget;

     private int mLastTouchClassification;
     private int mDistanceSinceScroll = 0;

     private boolean mIsInPreDrag;

     /**
      * Interface to receive notifications when a drag starts or stops
      */
     public interface DragListener {
         /**
          * A drag has begun
          *
          * @param dragObject The object being dragged
          * @param options Options used to start the drag
          */
         void onDragStart(DropTarget.DragObject dragObject, DragOptions options);

         /**
          * The drag has ended
          */
         void onDragEnd();
     }

     /**
      * Used to create a new DragLayer from XML.
      */
     public DragController(Launcher launcher) {
         mLauncher = launcher;
         mFlingToDeleteHelper = new FlingToDeleteHelper(launcher);
     }

     /**
      * Starts a drag.
      * When the drag is started, the UI automatically goes into spring loaded mode. On a successful
      * drop, it is the responsibility of the {@link DropTarget} to exit out of the spring loaded
      * mode. If the drop was cancelled for some reason, the UI will automatically exit out of this mode.
      *
      * @param b The bitmap to display as the drag image.  It will be re-scaled to the
      *          enlarged size.
      * @param originalView The source view (ie. icon, widget etc.) that is being dragged
      *          and which the DragView represents
      * @param dragLayerX The x position in the DragLayer of the left-top of the bitmap.
      * @param dragLayerY The y position in the DragLayer of the left-top of the bitmap.
      * @param source An object representing where the drag originated
      * @param dragInfo The data associated with the object that is being dragged
      * @param dragRegion Coordinates within the bitmap b for the position of item being dragged.
      *          Makes dragging feel more precise, e.g. you can clip out a transparent border
      */
     public DragView startDrag(Bitmap b, DraggableView originalView, int dragLayerX, int dragLayerY,
             DragSource source, ItemInfo dragInfo, Point dragOffset, Rect dragRegion,
             float initialDragViewScale, float dragViewScaleOnDrop, DragOptions options) {
         if (PROFILE_DRAWING_DURING_DRAG) {
             android.os.Debug.startMethodTracing("Launcher");
         }

         mLauncher.hideKeyboard();
         AbstractFloatingView.closeOpenViews(mLauncher, false, TYPE_DISCOVERY_BOUNCE);

         mOptions = options;
         if (mOptions.simulatedDndStartPoint != null) {
             mLastTouch.x = mMotionDown.x = mOptions.simulatedDndStartPoint.x;
             mLastTouch.y = mMotionDown.y = mOptions.simulatedDndStartPoint.y;
         }

         final int registrationX = mMotionDown.x - dragLayerX;
         final int registrationY = mMotionDown.y - dragLayerY;

         final int dragRegionLeft = dragRegion == null ? 0 : dragRegion.left;
         final int dragRegionTop = dragRegion == null ? 0 : dragRegion.top;

         mLastDropTarget = null;

         mDragObject = new DropTarget.DragObject(mLauncher.getApplicationContext());
         mDragObject.originalView = originalView;

         mIsInPreDrag = mOptions.preDragCondition != null
                 && !mOptions.preDragCondition.shouldStartDrag(0);

         final Resources res = mLauncher.getResources();
         final float scaleDps = mIsInPreDrag
                 ? res.getDimensionPixelSize(R.dimen.pre_drag_view_scale) : 0f;
         final DragView dragView = mDragObject.dragView = new DragView(mLauncher, b, registrationX,
                 registrationY, initialDragViewScale, dragViewScaleOnDrop, scaleDps);
         dragView.setItemInfo(dragInfo);
         mDragObject.dragComplete = false;

         mDragObject.xOffset = mMotionDown.x - (dragLayerX + dragRegionLeft);
         mDragObject.yOffset = mMotionDown.y - (dragLayerY + dragRegionTop);

         mDragDriver = DragDriver.create(this, mOptions, mFlingToDeleteHelper::recordMotionEvent);
         if (!mOptions.isAccessibleDrag) {
             mDragObject.stateAnnouncer = DragViewStateAnnouncer.createFor(dragView);
         }

         mDragObject.dragSource = source;
         mDragObject.dragInfo = dragInfo;
         mDragObject.originalDragInfo = mDragObject.dragInfo.makeShallowCopy();

         if (dragOffset != null) {
             dragView.setDragVisualizeOffset(new Point(dragOffset));
         }
         if (dragRegion != null) {
             dragView.setDragRegion(new Rect(dragRegion));
         }

         mLauncher.getDragLayer().performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
         dragView.show(mLastTouch.x, mLastTouch.y);
         mDistanceSinceScroll = 0;

         if (!mIsInPreDrag) {
             callOnDragStart();
         } else if (mOptions.preDragCondition != null) {
             mOptions.preDragCondition.onPreDragStart(mDragObject);
         }

         handleMoveEvent(mLastTouch.x, mLastTouch.y);
         mLauncher.getUserEventDispatcher().resetActionDurationMillis();

         if (!mLauncher.isTouchInProgress() && options.simulatedDndStartPoint == null) {
             // If it is an internal drag and the touch is already complete, cancel immediately
             MAIN_EXECUTOR.submit(this::cancelDrag);
         }
         return dragView;
     }

     private void callOnDragStart() {
         if (mOptions.preDragCondition != null) {
             mOptions.preDragCondition.onPreDragEnd(mDragObject, true /* dragStarted*/);
         }
         mIsInPreDrag = false;
         for (DragListener listener : new ArrayList<>(mListeners)) {
             listener.onDragStart(mDragObject, mOptions);
         }
     }

     public void addFirstFrameAnimationHelper(ValueAnimator anim) {
         if (mDragObject != null && mDragObject.dragView != null) {
             mDragObject.dragView.mFirstFrameAnimatorHelper.addTo(anim);
         }
     }

     /**
      * Call this from a drag source view like this:
      *
      * <pre>
      *  @Override
      *  public boolean dispatchKeyEvent(KeyEvent event) {
      *      return mDragController.dispatchKeyEvent(this, event)
      *              || super.dispatchKeyEvent(event);
      * </pre>
      */
     public boolean dispatchKeyEvent(KeyEvent event) {
         return mDragDriver != null;
     }

     public boolean isDragging() {
         return mDragDriver != null || (mOptions != null && mOptions.isAccessibleDrag);
     }

     /**
      * Stop dragging without dropping.
      */
     public void cancelDrag() {
         if (isDragging()) {
             if (mLastDropTarget != null) {
                 mLastDropTarget.onDragExit(mDragObject);
             }
             mDragObject.deferDragViewCleanupPostAnimation = false;
             mDragObject.cancelled = true;
             mDragObject.dragComplete = true;
             if (!mIsInPreDrag) {
                 dispatchDropComplete(null, false);
             }
         }
         endDrag();
     }

     private void dispatchDropComplete(View dropTarget, boolean accepted) {
         if (!accepted) {
             // If it was not accepted, cleanup the state. If it was accepted, it is the
             // responsibility of the drop target to cleanup the state.
             mLauncher.getStateManager().goToState(NORMAL, SPRING_LOADED_EXIT_DELAY);
             mDragObject.deferDragViewCleanupPostAnimation = false;
         }

         mDragObject.dragSource.onDropCompleted(dropTarget, mDragObject, accepted);
     }

     public void onAppsRemoved(ItemInfoMatcher matcher) {
         // Cancel the current drag if we are removing an app that we are dragging
         if (mDragObject != null) {
             ItemInfo dragInfo = mDragObject.dragInfo;
             if (dragInfo instanceof WorkspaceItemInfo) {
                 ComponentName cn = dragInfo.getTargetComponent();
                 if (cn != null && matcher.matches(dragInfo, cn)) {
                     cancelDrag();
                 }
             }
         }
     }

     private void endDrag() {
         if (isDragging()) {
             mDragDriver = null;
             boolean isDeferred = false;
             if (mDragObject.dragView != null) {
                 isDeferred = mDragObject.deferDragViewCleanupPostAnimation;
                 if (!isDeferred) {
                     mDragObject.dragView.remove();
                 } else if (mIsInPreDrag) {
                     animateDragViewToOriginalPosition(null, null, -1);
                 }
                 mDragObject.dragView = null;
             }

             // Only end the drag if we are not deferred
             if (!isDeferred) {
                 callOnDragEnd();
             }
         }

         mFlingToDeleteHelper.releaseVelocityTracker();
     }

     public void animateDragViewToOriginalPosition(final Runnable onComplete,
             final View originalIcon, int duration) {
         Runnable onCompleteRunnable = new Runnable() {
             @Override
             public void run() {
                 if (originalIcon != null) {
                     originalIcon.setVisibility(View.VISIBLE);
                 }
                 if (onComplete != null) {
                     onComplete.run();
                 }
             }
         };
         mDragObject.dragView.animateTo(mMotionDown.x, mMotionDown.y, onCompleteRunnable, duration);
     }

     private void callOnDragEnd() {
         if (mIsInPreDrag && mOptions.preDragCondition != null) {
             mOptions.preDragCondition.onPreDragEnd(mDragObject, false /* dragStarted*/);
         }
         mIsInPreDrag = false;
         mOptions = null;
         for (DragListener listener : new ArrayList<>(mListeners)) {
             listener.onDragEnd();
         }
     }

     /**
      * This only gets called as a result of drag view cleanup being deferred in endDrag();
      */
     void onDeferredEndDrag(DragView dragView) {
         dragView.remove();

         if (mDragObject.deferDragViewCleanupPostAnimation) {
             // If we skipped calling onDragEnd() before, do it now
             callOnDragEnd();
         }
     }

     /**
      * Clamps the position to the drag layer bounds.
      */
     private Point getClampedDragLayerPos(float x, float y) {
         mLauncher.getDragLayer().getLocalVisibleRect(mRectTemp);
         mTmpPoint.x = (int) Math.max(mRectTemp.left, Math.min(x, mRectTemp.right - 1));
         mTmpPoint.y = (int) Math.max(mRectTemp.top, Math.min(y, mRectTemp.bottom - 1));
         return mTmpPoint;
     }

     @Override
     public void onDriverDragMove(float x, float y) {
         Point dragLayerPos = getClampedDragLayerPos(x, y);
         handleMoveEvent(dragLayerPos.x, dragLayerPos.y);
     }

     @Override
     public void onDriverDragExitWindow() {
         if (mLastDropTarget != null) {
             mLastDropTarget.onDragExit(mDragObject);
             mLastDropTarget = null;
         }
     }

     @Override
     public void onDriverDragEnd(float x, float y) {
         DropTarget dropTarget;
         Runnable flingAnimation = mFlingToDeleteHelper.getFlingAnimation(mDragObject, mOptions);
         if (flingAnimation != null) {
             dropTarget = mFlingToDeleteHelper.getDropTarget();
         } else {
             dropTarget = findDropTarget((int) x, (int) y, mCoordinatesTemp);
         }

         drop(dropTarget, flingAnimation);

         endDrag();
     }

     @Override
     public void onDriverDragCancel() {
         cancelDrag();
     }

     /**
      * Call this from a drag source view.
      */
     @Override
     public boolean onControllerInterceptTouchEvent(MotionEvent ev) {
         if (mOptions != null && mOptions.isAccessibleDrag) {
             return false;
         }

         Point dragLayerPos = getClampedDragLayerPos(ev.getX(), ev.getY());
         mLastTouch.set(dragLayerPos.x,  dragLayerPos.y);
         if (ev.getAction() == MotionEvent.ACTION_DOWN) {
             // Remember location of down touch
             mMotionDown.set(dragLayerPos.x,  dragLayerPos.y);
         }

         if (ATLEAST_Q) {
             mLastTouchClassification = ev.getClassification();
         }
         return mDragDriver != null && mDragDriver.onInterceptTouchEvent(ev);
     }

     /**
      * Call this from a drag source view.
      */
     @Override
     public boolean onControllerTouchEvent(MotionEvent ev) {
         return mDragDriver != null && mDragDriver.onTouchEvent(ev);
     }

     /**
      * Call this from a drag source view.
      */
     public boolean onDragEvent(DragEvent event) {
         return mDragDriver != null && mDragDriver.onDragEvent(event);
     }

     private void handleMoveEvent(int x, int y) {
         mDragObject.dragView.move(x, y);

         // Drop on someone?
         final int[] coordinates = mCoordinatesTemp;
         DropTarget dropTarget = findDropTarget(x, y, coordinates);
         mDragObject.x = coordinates[0];
         mDragObject.y = coordinates[1];
         checkTouchMove(dropTarget);

         // Check if we are hovering over the scroll areas
         mDistanceSinceScroll += Math.hypot(mLastTouch.x - x, mLastTouch.y - y);
         mLastTouch.set(x, y);

         int distanceDragged = mDistanceSinceScroll;
         if (ATLEAST_Q && mLastTouchClassification == MotionEvent.CLASSIFICATION_DEEP_PRESS) {
             distanceDragged /= DEEP_PRESS_DISTANCE_FACTOR;
         }
         if (mIsInPreDrag && mOptions.preDragCondition != null
                 && mOptions.preDragCondition.shouldStartDrag(distanceDragged)) {
             callOnDragStart();
         }
     }

     public float getDistanceDragged() {
         return mDistanceSinceScroll;
     }

     public void forceTouchMove() {
         int[] placeholderCoordinates = mCoordinatesTemp;
         DropTarget dropTarget = findDropTarget(mLastTouch.x, mLastTouch.y, placeholderCoordinates);
         mDragObject.x = placeholderCoordinates[0];
         mDragObject.y = placeholderCoordinates[1];
         checkTouchMove(dropTarget);
     }

     private void checkTouchMove(DropTarget dropTarget) {
         if (dropTarget != null) {
             if (mLastDropTarget != dropTarget) {
                 if (mLastDropTarget != null) {
                     mLastDropTarget.onDragExit(mDragObject);
                 }
                 dropTarget.onDragEnter(mDragObject);
             }
             dropTarget.onDragOver(mDragObject);
         } else {
             if (mLastDropTarget != null) {
                 mLastDropTarget.onDragExit(mDragObject);
             }
         }
         mLastDropTarget = dropTarget;
     }

     /**
      * As above, since accessible drag and drop won't cause the same sequence of touch events,
      * we manually ensure appropriate drag and drop events get emulated for accessible drag.
      */
     public void completeAccessibleDrag(int[] location) {
         final int[] coordinates = mCoordinatesTemp;

         // We make sure that we prime the target for drop.
         DropTarget dropTarget = findDropTarget(location[0], location[1], coordinates);
         mDragObject.x = coordinates[0];
         mDragObject.y = coordinates[1];
         checkTouchMove(dropTarget);

         dropTarget.prepareAccessibilityDrop();
         // Perform the drop
         drop(dropTarget, null);
         endDrag();
     }

     private void drop(DropTarget dropTarget, Runnable flingAnimation) {
         final int[] coordinates = mCoordinatesTemp;
         mDragObject.x = coordinates[0];
         mDragObject.y = coordinates[1];

         // Move dragging to the final target.
         if (dropTarget != mLastDropTarget) {
             if (mLastDropTarget != null) {
                 mLastDropTarget.onDragExit(mDragObject);
             }
             mLastDropTarget = dropTarget;
             if (dropTarget != null) {
                 dropTarget.onDragEnter(mDragObject);
             }
         }

         mDragObject.dragComplete = true;
         if (mIsInPreDrag) {
             if (dropTarget != null) {
                 dropTarget.onDragExit(mDragObject);
             }
             return;
         }

         // Drop onto the target.
         boolean accepted = false;
         if (dropTarget != null) {
             dropTarget.onDragExit(mDragObject);
             if (dropTarget.acceptDrop(mDragObject)) {
                 if (flingAnimation != null) {
                     flingAnimation.run();
                 } else {
                     dropTarget.onDrop(mDragObject, mOptions);
                 }
                 accepted = true;
             }
         }
         final View dropTargetAsView = dropTarget instanceof View ? (View) dropTarget : null;
         mLauncher.getUserEventDispatcher().logDragNDrop(mDragObject, dropTargetAsView);
         dispatchDropComplete(dropTargetAsView, accepted);
     }

     private DropTarget findDropTarget(int x, int y, int[] dropCoordinates) {
         mDragObject.x = x;
         mDragObject.y = y;

         final Rect r = mRectTemp;
         final ArrayList<DropTarget> dropTargets = mDropTargets;
         final int count = dropTargets.size();
         for (int i = count - 1; i >= 0; i--) {
             DropTarget target = dropTargets.get(i);
             if (!target.isDropEnabled())
                 continue;

             target.getHitRectRelativeToDragLayer(r);
             if (r.contains(x, y)) {
                 dropCoordinates[0] = x;
                 dropCoordinates[1] = y;
                 mLauncher.getDragLayer().mapCoordInSelfToDescendant((View) target, dropCoordinates);
                 return target;
             }
         }
         // Pass all unhandled drag to workspace. Workspace finds the correct
         // cell layout to drop to in the existing drag/drop logic.
         dropCoordinates[0] = x;
         dropCoordinates[1] = y;
         mLauncher.getDragLayer().mapCoordInSelfToDescendant(mLauncher.getWorkspace(),
                 dropCoordinates);
         return mLauncher.getWorkspace();
     }

     /**
      * Sets the drag listener which will be notified when a drag starts or ends.
      */
     public void addDragListener(DragListener l) {
         mListeners.add(l);
     }

     /**
      * Remove a previously installed drag listener.
      */
     public void removeDragListener(DragListener l) {
         mListeners.remove(l);
     }

     /**
      * Add a DropTarget to the list of potential places to receive drop events.
      */
     public void addDropTarget(DropTarget target) {
         mDropTargets.add(target);
     }

     /**
      * Don't send drop events to <em>target</em> any more.
      */
     public void removeDropTarget(DropTarget target) {
         mDropTargets.remove(target);
     }
 }
	/*
	* 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.AbstractFloatingView.TYPE_DISCOVERY_BOUNCE;
	import static com.android.launcher3.LauncherAnimUtils.SPRING_LOADED_EXIT_DELAY;
	import static com.android.launcher3.LauncherState.NORMAL;
	import static com.android.launcher3.Utilities.ATLEAST_Q;
	import static com.android.launcher3.util.Executors.MAIN_EXECUTOR;

	import android.animation.ValueAnimator;
	import android.content.ComponentName;
	import android.content.res.Resources;
	import android.graphics.Bitmap;
	import android.graphics.Point;
	import android.graphics.Rect;
	import android.view.DragEvent;
	import android.view.HapticFeedbackConstants;
	import android.view.KeyEvent;
	import android.view.MotionEvent;
	import android.view.View;

	import com.android.launcher3.AbstractFloatingView;
	import com.android.launcher3.DragSource;
	import com.android.launcher3.DropTarget;
	import com.android.launcher3.Launcher;
	import com.android.launcher3.R;
	import com.android.launcher3.accessibility.DragViewStateAnnouncer;
	import com.android.launcher3.model.data.ItemInfo;
	import com.android.launcher3.model.data.WorkspaceItemInfo;
	import com.android.launcher3.util.ItemInfoMatcher;
	import com.android.launcher3.util.TouchController;

	import java.util.ArrayList;

	/**
	* Class for initiating a drag within a view or across multiple views.
	*/
	public class DragController implements DragDriver.EventListener, TouchController {
	private static final boolean PROFILE_DRAWING_DURING_DRAG = false;

	/**
	* When a drag is started from a deep press, you need to drag this much farther than normal to
	* end a pre-drag. See {@link DragOptions.PreDragCondition#shouldStartDrag(double)}.
	*/
	private static final int DEEP_PRESS_DISTANCE_FACTOR = 3;

	private final Launcher mLauncher;
	private final FlingToDeleteHelper mFlingToDeleteHelper;

	// temporaries to avoid gc thrash
	private final Rect mRectTemp = new Rect();
	private final int[] mCoordinatesTemp = new int[2];

	/**
	* Drag driver for the current drag/drop operation, or null if there is no active DND operation.
	* It's null during accessible drag operations.
	*/
	private DragDriver mDragDriver = null;

	/** Options controlling the drag behavior. */
	private DragOptions mOptions;

	/** Coordinate for motion down event */
	private final Point mMotionDown = new Point();
	/ Coordinate for last touch event /
	private final Point mLastTouch = new Point();

	private final Point mTmpPoint = new Point();

	private DropTarget.DragObject mDragObject;

	/** Who can receive drop events */
	private final ArrayList<DropTarget> mDropTargets = new ArrayList<>();
	private final ArrayList<DragListener> mListeners = new ArrayList<>();

	private DropTarget mLastDropTarget;

	private int mLastTouchClassification;
	private int mDistanceSinceScroll = 0;

	private boolean mIsInPreDrag;

	/**
	* Interface to receive notifications when a drag starts or stops
	*/
	public interface DragListener {
	/**
	* A drag has begun
	*
	* @param dragObject The object being dragged
	* @param options Options used to start the drag
	*/
	void onDragStart(DropTarget.DragObject dragObject, DragOptions options);

	/**
	* The drag has ended
	*/
	void onDragEnd();
	}

	/**
	* Used to create a new DragLayer from XML.
	*/
	public DragController(Launcher launcher) {
	mLauncher = launcher;
	mFlingToDeleteHelper = new FlingToDeleteHelper(launcher);
	}

	/**
	* Starts a drag.
	* When the drag is started, the UI automatically goes into spring loaded mode. On a successful
	* drop, it is the responsibility of the {@link DropTarget} to exit out of the spring loaded
	* mode. If the drop was cancelled for some reason, the UI will automatically exit out of this mode.
	*
	* @param b The bitmap to display as the drag image. It will be re-scaled to the
	* enlarged size.
	* @param originalView The source view (ie. icon, widget etc.) that is being dragged
	* and which the DragView represents
	* @param dragLayerX The x position in the DragLayer of the left-top of the bitmap.
	* @param dragLayerY The y position in the DragLayer of the left-top of the bitmap.
	* @param source An object representing where the drag originated
	* @param dragInfo The data associated with the object that is being dragged
	* @param dragRegion Coordinates within the bitmap b for the position of item being dragged.
	* Makes dragging feel more precise, e.g. you can clip out a transparent border
	*/
	public DragView startDrag(Bitmap b, DraggableView originalView, int dragLayerX, int dragLayerY,
	DragSource source, ItemInfo dragInfo, Point dragOffset, Rect dragRegion,
	float initialDragViewScale, float dragViewScaleOnDrop, DragOptions options) {
	if (PROFILE_DRAWING_DURING_DRAG) {
	android.os.Debug.startMethodTracing("Launcher");
	}

	mLauncher.hideKeyboard();
	AbstractFloatingView.closeOpenViews(mLauncher, false, TYPE_DISCOVERY_BOUNCE);

	mOptions = options;
	if (mOptions.simulatedDndStartPoint != null) {
	mLastTouch.x = mMotionDown.x = mOptions.simulatedDndStartPoint.x;
	mLastTouch.y = mMotionDown.y = mOptions.simulatedDndStartPoint.y;
	}

	final int registrationX = mMotionDown.x - dragLayerX;
	final int registrationY = mMotionDown.y - dragLayerY;

	final int dragRegionLeft = dragRegion == null ? 0 : dragRegion.left;
	final int dragRegionTop = dragRegion == null ? 0 : dragRegion.top;

	mLastDropTarget = null;

	mDragObject = new DropTarget.DragObject(mLauncher.getApplicationContext());
	mDragObject.originalView = originalView;

	mIsInPreDrag = mOptions.preDragCondition != null
	&& !mOptions.preDragCondition.shouldStartDrag(0);

	final Resources res = mLauncher.getResources();
	final float scaleDps = mIsInPreDrag
	? res.getDimensionPixelSize(R.dimen.pre_drag_view_scale) : 0f;
	final DragView dragView = mDragObject.dragView = new DragView(mLauncher, b, registrationX,
	registrationY, initialDragViewScale, dragViewScaleOnDrop, scaleDps);
	dragView.setItemInfo(dragInfo);
	mDragObject.dragComplete = false;

	mDragObject.xOffset = mMotionDown.x - (dragLayerX + dragRegionLeft);
	mDragObject.yOffset = mMotionDown.y - (dragLayerY + dragRegionTop);

	mDragDriver = DragDriver.create(this, mOptions, mFlingToDeleteHelper::recordMotionEvent);
	if (!mOptions.isAccessibleDrag) {
	mDragObject.stateAnnouncer = DragViewStateAnnouncer.createFor(dragView);
	}

	mDragObject.dragSource = source;
	mDragObject.dragInfo = dragInfo;
	mDragObject.originalDragInfo = mDragObject.dragInfo.makeShallowCopy();

	if (dragOffset != null) {
	dragView.setDragVisualizeOffset(new Point(dragOffset));
	}
	if (dragRegion != null) {
	dragView.setDragRegion(new Rect(dragRegion));
	}

	mLauncher.getDragLayer().performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
	dragView.show(mLastTouch.x, mLastTouch.y);
	mDistanceSinceScroll = 0;

	if (!mIsInPreDrag) {
	callOnDragStart();
	} else if (mOptions.preDragCondition != null) {
	mOptions.preDragCondition.onPreDragStart(mDragObject);
	}

	handleMoveEvent(mLastTouch.x, mLastTouch.y);
	mLauncher.getUserEventDispatcher().resetActionDurationMillis();

	if (!mLauncher.isTouchInProgress() && options.simulatedDndStartPoint == null) {
	// If it is an internal drag and the touch is already complete, cancel immediately
	MAIN_EXECUTOR.submit(this::cancelDrag);
	}
	return dragView;
	}

	private void callOnDragStart() {
	if (mOptions.preDragCondition != null) {
	mOptions.preDragCondition.onPreDragEnd(mDragObject, true /* dragStarted*/);
	}
	mIsInPreDrag = false;
	for (DragListener listener : new ArrayList<>(mListeners)) {
	listener.onDragStart(mDragObject, mOptions);
	}
	}

	public void addFirstFrameAnimationHelper(ValueAnimator anim) {
	if (mDragObject != null && mDragObject.dragView != null) {
	mDragObject.dragView.mFirstFrameAnimatorHelper.addTo(anim);
	}
	}

	/**
	* Call this from a drag source view like this:
	*
	* <pre>
	* @Override
	* public boolean dispatchKeyEvent(KeyEvent event) {
	* return mDragController.dispatchKeyEvent(this, event)
	* \|\| super.dispatchKeyEvent(event);
	* </pre>
	*/
	public boolean dispatchKeyEvent(KeyEvent event) {
	return mDragDriver != null;
	}

	public boolean isDragging() {
	return mDragDriver != null \|\| (mOptions != null && mOptions.isAccessibleDrag);
	}

	/**
	* Stop dragging without dropping.
	*/
	public void cancelDrag() {
	if (isDragging()) {
	if (mLastDropTarget != null) {
	mLastDropTarget.onDragExit(mDragObject);
	}
	mDragObject.deferDragViewCleanupPostAnimation = false;
	mDragObject.cancelled = true;
	mDragObject.dragComplete = true;
	if (!mIsInPreDrag) {
	dispatchDropComplete(null, false);
	}
	}
	endDrag();
	}

	private void dispatchDropComplete(View dropTarget, boolean accepted) {
	if (!accepted) {
	// If it was not accepted, cleanup the state. If it was accepted, it is the
	// responsibility of the drop target to cleanup the state.
	mLauncher.getStateManager().goToState(NORMAL, SPRING_LOADED_EXIT_DELAY);
	mDragObject.deferDragViewCleanupPostAnimation = false;
	}

	mDragObject.dragSource.onDropCompleted(dropTarget, mDragObject, accepted);
	}

	public void onAppsRemoved(ItemInfoMatcher matcher) {
	// Cancel the current drag if we are removing an app that we are dragging
	if (mDragObject != null) {
	ItemInfo dragInfo = mDragObject.dragInfo;
	if (dragInfo instanceof WorkspaceItemInfo) {
	ComponentName cn = dragInfo.getTargetComponent();
	if (cn != null && matcher.matches(dragInfo, cn)) {
	cancelDrag();
	}
	}
	}
	}

	private void endDrag() {
	if (isDragging()) {
	mDragDriver = null;
	boolean isDeferred = false;
	if (mDragObject.dragView != null) {
	isDeferred = mDragObject.deferDragViewCleanupPostAnimation;
	if (!isDeferred) {
	mDragObject.dragView.remove();
	} else if (mIsInPreDrag) {
	animateDragViewToOriginalPosition(null, null, -1);
	}
	mDragObject.dragView = null;
	}

	// Only end the drag if we are not deferred
	if (!isDeferred) {
	callOnDragEnd();
	}
	}

	mFlingToDeleteHelper.releaseVelocityTracker();
	}

	public void animateDragViewToOriginalPosition(final Runnable onComplete,
	final View originalIcon, int duration) {
	Runnable onCompleteRunnable = new Runnable() {
	@Override
	public void run() {
	if (originalIcon != null) {
	originalIcon.setVisibility(View.VISIBLE);
	}
	if (onComplete != null) {
	onComplete.run();
	}
	}
	};
	mDragObject.dragView.animateTo(mMotionDown.x, mMotionDown.y, onCompleteRunnable, duration);
	}

	private void callOnDragEnd() {
	if (mIsInPreDrag && mOptions.preDragCondition != null) {
	mOptions.preDragCondition.onPreDragEnd(mDragObject, false /* dragStarted*/);
	}
	mIsInPreDrag = false;
	mOptions = null;
	for (DragListener listener : new ArrayList<>(mListeners)) {
	listener.onDragEnd();
	}
	}

	/**
	* This only gets called as a result of drag view cleanup being deferred in endDrag();
	*/
	void onDeferredEndDrag(DragView dragView) {
	dragView.remove();

	if (mDragObject.deferDragViewCleanupPostAnimation) {
	// If we skipped calling onDragEnd() before, do it now
	callOnDragEnd();
	}
	}

	/**
	* Clamps the position to the drag layer bounds.
	*/
	private Point getClampedDragLayerPos(float x, float y) {
	mLauncher.getDragLayer().getLocalVisibleRect(mRectTemp);
	mTmpPoint.x = (int) Math.max(mRectTemp.left, Math.min(x, mRectTemp.right - 1));
	mTmpPoint.y = (int) Math.max(mRectTemp.top, Math.min(y, mRectTemp.bottom - 1));
	return mTmpPoint;
	}

	@Override
	public void onDriverDragMove(float x, float y) {
	Point dragLayerPos = getClampedDragLayerPos(x, y);
	handleMoveEvent(dragLayerPos.x, dragLayerPos.y);
	}

	@Override
	public void onDriverDragExitWindow() {
	if (mLastDropTarget != null) {
	mLastDropTarget.onDragExit(mDragObject);
	mLastDropTarget = null;
	}
	}

	@Override
	public void onDriverDragEnd(float x, float y) {
	DropTarget dropTarget;
	Runnable flingAnimation = mFlingToDeleteHelper.getFlingAnimation(mDragObject, mOptions);
	if (flingAnimation != null) {
	dropTarget = mFlingToDeleteHelper.getDropTarget();
	} else {
	dropTarget = findDropTarget((int) x, (int) y, mCoordinatesTemp);
	}

	drop(dropTarget, flingAnimation);

	endDrag();
	}

	@Override
	public void onDriverDragCancel() {
	cancelDrag();
	}

	/**
	* Call this from a drag source view.
	*/
	@Override
	public boolean onControllerInterceptTouchEvent(MotionEvent ev) {
	if (mOptions != null && mOptions.isAccessibleDrag) {
	return false;
	}

	Point dragLayerPos = getClampedDragLayerPos(ev.getX(), ev.getY());
	mLastTouch.set(dragLayerPos.x, dragLayerPos.y);
	if (ev.getAction() == MotionEvent.ACTION_DOWN) {
	// Remember location of down touch
	mMotionDown.set(dragLayerPos.x, dragLayerPos.y);
	}

	if (ATLEAST_Q) {
	mLastTouchClassification = ev.getClassification();
	}
	return mDragDriver != null && mDragDriver.onInterceptTouchEvent(ev);
	}

	/**
	* Call this from a drag source view.
	*/
	@Override
	public boolean onControllerTouchEvent(MotionEvent ev) {
	return mDragDriver != null && mDragDriver.onTouchEvent(ev);
	}

	/**
	* Call this from a drag source view.
	*/
	public boolean onDragEvent(DragEvent event) {
	return mDragDriver != null && mDragDriver.onDragEvent(event);
	}

	private void handleMoveEvent(int x, int y) {
	mDragObject.dragView.move(x, y);

	// Drop on someone?
	final int[] coordinates = mCoordinatesTemp;
	DropTarget dropTarget = findDropTarget(x, y, coordinates);
	mDragObject.x = coordinates[0];
	mDragObject.y = coordinates[1];
	checkTouchMove(dropTarget);

	// Check if we are hovering over the scroll areas
	mDistanceSinceScroll += Math.hypot(mLastTouch.x - x, mLastTouch.y - y);
	mLastTouch.set(x, y);

	int distanceDragged = mDistanceSinceScroll;
	if (ATLEAST_Q && mLastTouchClassification == MotionEvent.CLASSIFICATION_DEEP_PRESS) {
	distanceDragged /= DEEP_PRESS_DISTANCE_FACTOR;
	}
	if (mIsInPreDrag && mOptions.preDragCondition != null
	&& mOptions.preDragCondition.shouldStartDrag(distanceDragged)) {
	callOnDragStart();
	}
	}

	public float getDistanceDragged() {
	return mDistanceSinceScroll;
	}

	public void forceTouchMove() {
	int[] placeholderCoordinates = mCoordinatesTemp;
	DropTarget dropTarget = findDropTarget(mLastTouch.x, mLastTouch.y, placeholderCoordinates);
	mDragObject.x = placeholderCoordinates[0];
	mDragObject.y = placeholderCoordinates[1];
	checkTouchMove(dropTarget);
	}

	private void checkTouchMove(DropTarget dropTarget) {
	if (dropTarget != null) {
	if (mLastDropTarget != dropTarget) {
	if (mLastDropTarget != null) {
	mLastDropTarget.onDragExit(mDragObject);
	}
	dropTarget.onDragEnter(mDragObject);
	}
	dropTarget.onDragOver(mDragObject);
	} else {
	if (mLastDropTarget != null) {
	mLastDropTarget.onDragExit(mDragObject);
	}
	}
	mLastDropTarget = dropTarget;
	}

	/**
	* As above, since accessible drag and drop won't cause the same sequence of touch events,
	* we manually ensure appropriate drag and drop events get emulated for accessible drag.
	*/
	public void completeAccessibleDrag(int[] location) {
	final int[] coordinates = mCoordinatesTemp;

	// We make sure that we prime the target for drop.
	DropTarget dropTarget = findDropTarget(location[0], location[1], coordinates);
	mDragObject.x = coordinates[0];
	mDragObject.y = coordinates[1];
	checkTouchMove(dropTarget);

	dropTarget.prepareAccessibilityDrop();
	// Perform the drop
	drop(dropTarget, null);
	endDrag();
	}

	private void drop(DropTarget dropTarget, Runnable flingAnimation) {
	final int[] coordinates = mCoordinatesTemp;
	mDragObject.x = coordinates[0];
	mDragObject.y = coordinates[1];

	// Move dragging to the final target.
	if (dropTarget != mLastDropTarget) {
	if (mLastDropTarget != null) {
	mLastDropTarget.onDragExit(mDragObject);
	}
	mLastDropTarget = dropTarget;
	if (dropTarget != null) {
	dropTarget.onDragEnter(mDragObject);
	}
	}

	mDragObject.dragComplete = true;
	if (mIsInPreDrag) {
	if (dropTarget != null) {
	dropTarget.onDragExit(mDragObject);
	}
	return;
	}

	// Drop onto the target.
	boolean accepted = false;
	if (dropTarget != null) {
	dropTarget.onDragExit(mDragObject);
	if (dropTarget.acceptDrop(mDragObject)) {
	if (flingAnimation != null) {
	flingAnimation.run();
	} else {
	dropTarget.onDrop(mDragObject, mOptions);
	}
	accepted = true;
	}
	}
	final View dropTargetAsView = dropTarget instanceof View ? (View) dropTarget : null;
	mLauncher.getUserEventDispatcher().logDragNDrop(mDragObject, dropTargetAsView);
	dispatchDropComplete(dropTargetAsView, accepted);
	}

	private DropTarget findDropTarget(int x, int y, int[] dropCoordinates) {
	mDragObject.x = x;
	mDragObject.y = y;

	final Rect r = mRectTemp;
	final ArrayList<DropTarget> dropTargets = mDropTargets;
	final int count = dropTargets.size();
	for (int i = count - 1; i >= 0; i--) {
	DropTarget target = dropTargets.get(i);
	if (!target.isDropEnabled())
	continue;

	target.getHitRectRelativeToDragLayer(r);
	if (r.contains(x, y)) {
	dropCoordinates[0] = x;
	dropCoordinates[1] = y;
	mLauncher.getDragLayer().mapCoordInSelfToDescendant((View) target, dropCoordinates);
	return target;
	}
	}
	// Pass all unhandled drag to workspace. Workspace finds the correct
	// cell layout to drop to in the existing drag/drop logic.
	dropCoordinates[0] = x;
	dropCoordinates[1] = y;
	mLauncher.getDragLayer().mapCoordInSelfToDescendant(mLauncher.getWorkspace(),
	dropCoordinates);
	return mLauncher.getWorkspace();
	}

	/**
	* Sets the drag listener which will be notified when a drag starts or ends.
	*/
	public void addDragListener(DragListener l) {
	mListeners.add(l);
	}

	/**
	* Remove a previously installed drag listener.
	*/
	public void removeDragListener(DragListener l) {
	mListeners.remove(l);
	}

	/**
	* Add a DropTarget to the list of potential places to receive drop events.
	*/
	public void addDropTarget(DropTarget target) {
	mDropTargets.add(target);
	}

	/**
	* Don't send drop events to <em>target</em> any more.
	*/
	public void removeDropTarget(DropTarget target) {
	mDropTargets.remove(target);
	}
	}