content: /*
   * Copyright (C) 2016 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.util;
  
  import android.graphics.Rect;
  import android.graphics.RectF;
  import android.view.MotionEvent;
  import android.view.TouchDelegate;
  import android.view.View;
  
  /**
   * This class differs from the framework {@link TouchDelegate} in that it transforms the
   * coordinates of the motion event to the provided bounds.
   *
   * You can also modify the bounds post construction. Since the bounds are available during layout,
   * this avoids new object creation during every layout.
   */
  public class TransformingTouchDelegate extends TouchDelegate {
      private static final Rect sTempRect = new Rect();
  
      private final RectF mBounds;
  
      private final RectF mTouchCheckBounds;
      private float mTouchExtension;
      private boolean mWasTouchOutsideBounds;
  
      private View mDelegateView;
      private boolean mDelegateTargeted;
  
      public TransformingTouchDelegate(View delegateView) {
          super(sTempRect, delegateView);
  
          mDelegateView = delegateView;
          mBounds = new RectF();
          mTouchCheckBounds = new RectF();
      }
  
      public void setBounds(int left, int top, int right, int bottom) {
          mBounds.set(left, top, right, bottom);
          updateTouchBounds();
      }
  
      public void extendTouchBounds(float extension) {
          mTouchExtension = extension;
          updateTouchBounds();
      }
  
      private void updateTouchBounds() {
          mTouchCheckBounds.set(mBounds);
          mTouchCheckBounds.inset(-mTouchExtension, -mTouchExtension);
      }
  
      public void setDelegateView(View view) {
          mDelegateView = view;
      }
  
      /**
       * Will forward touch events to the delegate view if the event is within the bounds
       * specified in the constructor.
       *
       * @param event The touch event to forward
       * @return True if the event was forwarded to the delegate, false otherwise.
       */
      public boolean onTouchEvent(MotionEvent event) {
          boolean sendToDelegate = false;
          switch (event.getAction()) {
              case MotionEvent.ACTION_DOWN:
                  mDelegateTargeted = mTouchCheckBounds.contains(event.getX(), event.getY());
                  if (mDelegateTargeted) {
                      mWasTouchOutsideBounds = !mBounds.contains(event.getX(), event.getY());
                      sendToDelegate = true;
                  }
                  break;
              case MotionEvent.ACTION_MOVE:
                  sendToDelegate = mDelegateTargeted;
                  break;
              case MotionEvent.ACTION_UP:
              case MotionEvent.ACTION_CANCEL:
                  sendToDelegate = mDelegateTargeted;
                  mDelegateTargeted = false;
                  break;
          }
          boolean handled = false;
          if (sendToDelegate) {
              float x = event.getX();
              float y = event.getY();
              if (mWasTouchOutsideBounds) {
                  event.setLocation(mBounds.centerX(), mBounds.centerY());
              } else {
                  event.offsetLocation(-mBounds.left, -mBounds.top);
              }
              handled = mDelegateView.dispatchTouchEvent(event);
              event.setLocation(x, y);
          }
          return handled;
      }
  }
  