java/com/android/dialer/app/list/ContentChangedFilter.java

/*
 * 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.dialer.app.list;

import android.view.View;
import android.view.View.AccessibilityDelegate;
import android.view.ViewGroup;
import android.view.accessibility.AccessibilityEvent;

/**
 * AccessibilityDelegate that will filter out TYPE_WINDOW_CONTENT_CHANGED Used to suppress "Showing
 * items x of y" from firing of ListView whenever it's content changes. AccessibilityEvent can only
 * be rejected at a view's parent once it is generated, use addToParent() to add this delegate to
 * the parent.
 */
public class ContentChangedFilter extends AccessibilityDelegate {

  // the view we don't want TYPE_WINDOW_CONTENT_CHANGED to fire.
  private View view;

  private ContentChangedFilter(View view) {
    super();
    this.view = view;
  }

  /** Add this delegate to the parent of @param view to filter out TYPE_WINDOW_CONTENT_CHANGED */
  public static void addToParent(View view) {
    View parent = (View) view.getParent();
    parent.setAccessibilityDelegate(new ContentChangedFilter(view));
  }

  @Override
  public boolean onRequestSendAccessibilityEvent(
      ViewGroup host, View child, AccessibilityEvent event) {
    if (child == view) {
      if (event.getEventType() == AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED) {
        return false;
      }
    }
    return super.onRequestSendAccessibilityEvent(host, child, event);
  }
}