content: /*
   * Copyright (C) 2017 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.server.wm;
  
  import static android.view.InputDevice.SOURCE_CLASS_POINTER;
  import static android.view.MotionEvent.ACTION_CANCEL;
  import static android.view.MotionEvent.ACTION_DOWN;
  import static android.view.MotionEvent.ACTION_MOVE;
  import static android.view.MotionEvent.ACTION_UP;
  import static android.view.MotionEvent.BUTTON_STYLUS_PRIMARY;
  import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_DRAG;
  import static com.android.server.wm.WindowManagerDebugConfig.TAG_WM;
  
  import android.os.Looper;
  import android.util.Slog;
  import android.view.InputChannel;
  import android.view.InputDevice;
  import android.view.InputEvent;
  import android.view.InputEventReceiver;
  import android.view.MotionEvent;
  
  /**
   * Input receiver for drag and drop
   */
  class DragInputEventReceiver extends InputEventReceiver {
      private final DragDropController mDragDropController;
  
      // Set, if stylus button was down at the start of the drag.
      private boolean mStylusButtonDownAtStart;
      // Indicates the first event to check for button state.
      private boolean mIsStartEvent = true;
      // Set to true to ignore input events after the drag gesture is complete but the drag events
      // are still being dispatched.
      private boolean mMuteInput = false;
  
      DragInputEventReceiver(InputChannel inputChannel, Looper looper,
              DragDropController controller) {
          super(inputChannel, looper);
          mDragDropController = controller;
      }
  
      @Override
      public void onInputEvent(InputEvent event) {
          boolean handled = false;
          try {
              if (!(event instanceof MotionEvent)
                      || (event.getSource() & SOURCE_CLASS_POINTER) == 0
                      || mMuteInput) {
                  return;
              }
              final MotionEvent motionEvent = (MotionEvent) event;
              final float newX = motionEvent.getRawX();
              final float newY = motionEvent.getRawY();
              final boolean isStylusButtonDown =
                      (motionEvent.getButtonState() & BUTTON_STYLUS_PRIMARY) != 0;
  
              if (mIsStartEvent) {
                  // First event and the button was down, check for the button being
                  // lifted in the future, if that happens we'll drop the item.
                  mStylusButtonDownAtStart = isStylusButtonDown;
                  mIsStartEvent = false;
              }
  
              switch (motionEvent.getAction()) {
                  case ACTION_DOWN:
                      if (DEBUG_DRAG) Slog.w(TAG_WM, "Unexpected ACTION_DOWN in drag layer");
                      return;
                  case ACTION_MOVE:
                      if (mStylusButtonDownAtStart && !isStylusButtonDown) {
                          if (DEBUG_DRAG) {
                              Slog.d(TAG_WM, "Button no longer pressed; dropping at " + newX + ","
                                      + newY);
                          }
                          mMuteInput = true;
                      }
                      break;
                  case ACTION_UP:
                      if (DEBUG_DRAG) {
                          Slog.d(TAG_WM, "Got UP on move channel; dropping at " + newX + "," + newY);
                      }
                      mMuteInput = true;
                      break;
                  case ACTION_CANCEL:
                      if (DEBUG_DRAG) Slog.d(TAG_WM, "Drag cancelled!");
                      mMuteInput = true;
                      break;
                  default:
                      return;
              }
  
              mDragDropController.handleMotionEvent(!mMuteInput /* keepHandling */, newX, newY);
              handled = true;
          } catch (Exception e) {
              Slog.e(TAG_WM, "Exception caught by drag handleMotion", e);
          } finally {
              finishInputEvent(event, handled);
          }
      }
  }
  