/talkback_preics/src/com/google/android/marvin/talkback/BasePackageMonitor.java
Java | 108 lines | 50 code | 13 blank | 45 comment | 10 complexity | d7c61e32b335c8e481e95bc1ed314b9c MD5 | raw file
1/* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package com.google.android.marvin.talkback; 18 19import android.content.BroadcastReceiver; 20import android.content.Context; 21import android.content.Intent; 22import android.content.IntentFilter; 23import android.net.Uri; 24 25/** 26 * Helper class for monitoring packages on the system. 27 */ 28public class BasePackageMonitor extends BroadcastReceiver { 29 30 /** 31 * The intent filter to match package modifications. 32 */ 33 final IntentFilter mPackageFilter = new IntentFilter(); 34 35 /** 36 * The context in which this monitor is registered. 37 */ 38 private Context mRegisteredContext; 39 40 /** 41 * Creates a new instance. 42 */ 43 public BasePackageMonitor() { 44 mPackageFilter.addAction(Intent.ACTION_PACKAGE_ADDED); 45 mPackageFilter.addAction(Intent.ACTION_PACKAGE_REMOVED); 46 mPackageFilter.addAction(Intent.ACTION_PACKAGE_CHANGED); 47 mPackageFilter.addDataScheme("package"); 48 } 49 50 /** 51 * Register this monitor via the given <code>context</code>. 52 */ 53 public void register(Context context) { 54 if (mRegisteredContext != null) { 55 throw new IllegalStateException("Already registered"); 56 } 57 mRegisteredContext = context; 58 context.registerReceiver(this, mPackageFilter); 59 } 60 61 /** 62 * Unregister this monitor. 63 */ 64 public void unregister() { 65 if (mRegisteredContext == null) { 66 throw new IllegalStateException("Not registered"); 67 } 68 mRegisteredContext.unregisterReceiver(this); 69 mRegisteredContext = null; 70 } 71 72 @Override 73 public void onReceive(Context context, Intent intent) { 74 String packageName = getPackageName(intent); 75 String action = intent.getAction(); 76 if (Intent.ACTION_PACKAGE_ADDED.equals(action)) { 77 onPackageAdded(packageName); 78 } else if (Intent.ACTION_PACKAGE_REMOVED.equals(action)) { 79 onPackageRemoved(packageName); 80 } else if (Intent.ACTION_PACKAGE_CHANGED.equals(action)) { 81 onPackageChanged(packageName); 82 } 83 } 84 85 /** 86 * @return The name of the package from an <code>intent</code>. 87 */ 88 private String getPackageName(Intent intent) { 89 Uri uri = intent.getData(); 90 String packageName = uri != null ? uri.getSchemeSpecificPart() : null; 91 return packageName; 92 } 93 94 /** 95 * Called when a <code>packageName</code> is added. 96 */ 97 protected void onPackageAdded(String packageName) {} 98 99 /** 100 * Called when a <code>packageName</code> is removed. 101 */ 102 protected void onPackageRemoved(String packageName) {} 103 104 /** 105 * Called when a <code>packageName</code> is changes. 106 */ 107 protected void onPackageChanged(String packageName) {} 108}