java/com/android/dialer/dialpadview/DialpadKeyButton.java

/*
 * Copyright (C) 2012 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.dialpadview;

import android.content.Context;
import android.graphics.RectF;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityManager;
import android.view.accessibility.AccessibilityNodeInfo;
import android.view.accessibility.AccessibilityNodeInfo.AccessibilityAction;
import android.widget.FrameLayout;

/**
 * Custom class for dialpad buttons.
 *
 * <p>When touch exploration mode is enabled for accessibility, this class implements the
 * lift-to-type interaction model:
 *
 * <ul>
 * <li>Hovering over the button will cause it to gain accessibility focus
 * <li>Removing the hover pointer while inside the bounds of the button will perform a click action
 * <li>If long-click is supported, hovering over the button for a longer period of time will switch
 *     to the long-click action
 * <li>Moving the hover pointer outside of the bounds of the button will restore to the normal click
 *     action
 *     <ul>
 */
public class DialpadKeyButton extends FrameLayout {

  /** Accessibility manager instance used to check touch exploration state. */
  private AccessibilityManager accessibilityManager;

  /** Bounds used to filter HOVER_EXIT events. */
  private RectF hoverBounds = new RectF();

  /** Alternate content description for long-hover state. */
  private CharSequence longHoverContentDesc;

  /** Backup of clickable property. Used for accessibility. */
  private boolean wasClickable;

  /** Backup of long-clickable property. Used for accessibility. */
  private boolean wasLongClickable;

  private OnPressedListener onPressedListener;

  public DialpadKeyButton(Context context, AttributeSet attrs) {
    super(context, attrs);
    initForAccessibility(context);
  }

  public DialpadKeyButton(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    initForAccessibility(context);
  }

  public void setOnPressedListener(OnPressedListener onPressedListener) {
    this.onPressedListener = onPressedListener;
  }

  private void initForAccessibility(Context context) {
    accessibilityManager =
        (AccessibilityManager) context.getSystemService(Context.ACCESSIBILITY_SERVICE);
  }

  public void setLongHoverContentDescription(CharSequence contentDescription) {
    longHoverContentDesc = contentDescription;
  }

  @Override
  public void setPressed(boolean pressed) {
    super.setPressed(pressed);
    if (onPressedListener != null) {
      onPressedListener.onPressed(this, pressed);
    }
  }

  @Override
  public void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);

    hoverBounds.left = getPaddingLeft();
    hoverBounds.right = w - getPaddingRight();
    hoverBounds.top = getPaddingTop();
    hoverBounds.bottom = h - getPaddingBottom();
  }

  @Override
  public boolean performAccessibilityAction(int action, Bundle arguments) {
    if (action == AccessibilityNodeInfo.ACTION_CLICK) {
      simulateClickForAccessibility();
      return true;
    }

    return super.performAccessibilityAction(action, arguments);
  }

  @Override
  public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
    super.onInitializeAccessibilityNodeInfo(info);
    // If the button has a long hover description, ask talkback to announce the action follow by
    // the description (for example "double tap and hold to call voicemail").
    if (!TextUtils.isEmpty(longHoverContentDesc)) {
      AccessibilityAction longClickAction =
          new AccessibilityAction(AccessibilityNodeInfo.ACTION_LONG_CLICK, longHoverContentDesc);
      info.addAction(longClickAction);
    }
  }

  @Override
  public boolean onHoverEvent(MotionEvent event) {
    // When touch exploration is turned on, lifting a finger while inside
    // the button's hover target bounds should perform a click action.
    if (accessibilityManager.isEnabled() && accessibilityManager.isTouchExplorationEnabled()) {
      switch (event.getActionMasked()) {
        case MotionEvent.ACTION_HOVER_ENTER:
          // Lift-to-type temporarily disables double-tap activation.
          wasClickable = isClickable();
          wasLongClickable = isLongClickable();
          setClickable(false);
          setLongClickable(false);
          break;
        case MotionEvent.ACTION_HOVER_EXIT:
          if (hoverBounds.contains(event.getX(), event.getY())) {
            simulateClickForAccessibility();
          }

          setClickable(wasClickable);
          setLongClickable(wasLongClickable);
          break;
        default: // No-op
          break;
      }
    }

    return super.onHoverEvent(event);
  }

  /**
   * When accessibility is on, simulate press and release to preserve the semantic meaning of
   * performClick(). Required for Braille support.
   */
  private void simulateClickForAccessibility() {
    // Checking the press state prevents double activation.
    if (isPressed()) {
      return;
    }

    setPressed(true);

    // Stay consistent with performClick() by sending the event after
    // setting the pressed state but before performing the action.
    sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);

    setPressed(false);
  }

  public interface OnPressedListener {

    void onPressed(View view, boolean pressed);
  }
}