| /* |
| * Copyright (C) 2011 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.example.android.supportv4.accessibility; |
| |
| import android.app.Activity; |
| import android.content.Context; |
| import android.os.Bundle; |
| import android.support.v4.view.AccessibilityDelegateCompat; |
| import android.support.v4.view.ViewCompat; |
| import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat; |
| import android.util.AttributeSet; |
| import android.view.View; |
| import android.view.accessibility.AccessibilityEvent; |
| |
| import com.example.android.supportv4.R; |
| |
| /** |
| * This class demonstrates how to use the support library to register |
| * a View.AccessibilityDelegate that customizes the accessibility |
| * behavior of a View. Aiming to maximize simplicity this example |
| * tweaks the text reported to accessibility services but using |
| * these APIs a client can inject any accessibility functionality into |
| * a View. |
| */ |
| public class AccessibilityDelegateSupportActivity extends Activity { |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public void onCreate(Bundle savedInstanceState) { |
| super.onCreate(savedInstanceState); |
| setContentView(R.layout.accessibility_delegate); |
| } |
| |
| /** |
| * This class represents a View that is customized via an AccessibilityDelegate |
| * as opposed to inheritance. An accessibility delegate can be used for adding |
| * accessibility to custom Views, i.e. ones that extend classes from android.view, |
| * in a backwards compatible fashion. Note that overriding a method whose return |
| * type or arguments are not part of a target platform APIs makes your application |
| * not backwards compatible with that platform version. |
| */ |
| public static class AccessibilityDelegateSupportView extends View { |
| |
| public AccessibilityDelegateSupportView(Context context, AttributeSet attrs) { |
| super(context, attrs); |
| installAccessibilityDelegate(); |
| } |
| |
| private void installAccessibilityDelegate() { |
| // The accessibility delegate enables customizing accessibility behavior |
| // via composition as opposed as inheritance. The main benefit is that |
| // one can write a backwards compatible application by setting the delegate |
| // only if the API level is high enough i.e. the delegate is part of the APIs. |
| // The easiest way to achieve that is by using the support library which |
| // takes the burden of checking API version and knowing which API version |
| // introduced the delegate off the developer. |
| ViewCompat.setAccessibilityDelegate(this, new AccessibilityDelegateCompat() { |
| @Override |
| public void onPopulateAccessibilityEvent(View host, AccessibilityEvent event) { |
| super.onPopulateAccessibilityEvent(host, event); |
| // Note that View.onPopulateAccessibilityEvent was introduced in |
| // ICS and we would like to tweak a bit the text that is reported to |
| // accessibility services via the AccessibilityEvent. |
| event.getText().add(getContext().getString( |
| R.string.accessibility_delegate_custom_text_added)); |
| } |
| |
| @Override |
| public void onInitializeAccessibilityNodeInfo(View host, |
| AccessibilityNodeInfoCompat info) { |
| super.onInitializeAccessibilityNodeInfo(host, info); |
| // Note that View.onInitializeAccessibilityNodeInfo was introduced in |
| // ICS and we would like to tweak a bit the text that is reported to |
| // accessibility services via the AccessibilityNodeInfo. |
| info.setText(getContext().getString( |
| R.string.accessibility_delegate_custom_text_added)); |
| } |
| }); |
| } |
| } |
| } |