content: /*
   * Copyright (C) 2018 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.view;
  
  import android.content.Context;
  import android.os.Build;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * Compatibility processor for InputEvents that allows events to be adjusted before and
   * after it is sent to the application.
   *
   * {@hide}
   */
  public class InputEventCompatProcessor {
  
      protected Context mContext;
      protected int mTargetSdkVersion;
  
      /** List of events to be used to return the processed events */
      private List<InputEvent> mProcessedEvents;
  
      public InputEventCompatProcessor(Context context) {
          mContext = context;
          mTargetSdkVersion = context.getApplicationInfo().targetSdkVersion;
          mProcessedEvents = new ArrayList<>();
      }
  
      /**
       * Processes the InputEvent for compatibility before it is sent to the app, allowing for the
       * generation of more than one event if necessary.
       *
       * @param e The InputEvent to process
       * @return The list of adjusted events, or null if no adjustments are needed. Do not keep a
       *         reference to the output as the list is reused.
       */
      public List<InputEvent> processInputEventForCompatibility(InputEvent e) {
          if (mTargetSdkVersion < Build.VERSION_CODES.M && e instanceof MotionEvent) {
              mProcessedEvents.clear();
              MotionEvent motion = (MotionEvent) e;
              final int mask =
                      MotionEvent.BUTTON_STYLUS_PRIMARY | MotionEvent.BUTTON_STYLUS_SECONDARY;
              final int buttonState = motion.getButtonState();
              final int compatButtonState = (buttonState & mask) >> 4;
              if (compatButtonState != 0) {
                  motion.setButtonState(buttonState | compatButtonState);
              }
              mProcessedEvents.add(motion);
              return mProcessedEvents;
          }
          return null;
      }
  
      /**
       * Processes the InputEvent for compatibility before it is finished by calling
       * InputEventReceiver#finishInputEvent().
       *
       * @param e The InputEvent to process
       * @return The InputEvent to finish, or null if it should not be finished
       */
      public InputEvent processInputEventBeforeFinish(InputEvent e) {
          // No changes needed
          return e;
      }
  }
  