RegisteredMediaRouteProviderWatcher.java revision f03da4a9e6cc02251c2f804eb6f25da61821d6a7 
1/*
2 * Copyright (C) 2013 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 android.support.v7.media;
18
19import android.content.BroadcastReceiver;
20import android.content.ComponentName;
21import android.content.Context;
22import android.content.Intent;
23import android.content.IntentFilter;
24import android.content.pm.PackageManager;
25import android.content.pm.ResolveInfo;
26import android.content.pm.ServiceInfo;
27
28import java.util.ArrayList;
29import java.util.Collections;
30
31/**
32 * Watches for media route provider services to be installed.
33 * Adds a provider to the media router for each registered service.
34 *
35 * @see RegisteredMediaRouteProvider
36 */
37final class RegisteredMediaRouteProviderWatcher {
38    private final Context mContext;
39    private final MediaRouter mRouter;
40    private final ArrayList<RegisteredMediaRouteProvider> mProviders =
41            new ArrayList<RegisteredMediaRouteProvider>();
42    private final PackageManager mPackageManager;
43
44    public RegisteredMediaRouteProviderWatcher(Context context, MediaRouter router) {
45        mContext = context;
46        mRouter = router;
47        mPackageManager = context.getPackageManager();
48    }
49
50    public void start() {
51        IntentFilter filter = new IntentFilter();
52        filter.addAction(Intent.ACTION_PACKAGE_ADDED);
53        filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
54        filter.addAction(Intent.ACTION_PACKAGE_CHANGED);
55        mContext.registerReceiver(new BroadcastReceiver() {
56            @Override
57            public void onReceive(Context context, Intent intent) {
58                scanPackages();
59            }
60        }, filter);
61
62        scanPackages();
63    }
64
65    private void scanPackages() {
66        // Add providers for all new services.
67        // Reorder the list so that providers left at the end will be the ones to remove.
68        int targetIndex = 0;
69        Intent intent = new Intent(MediaRouteProviderService.SERVICE_INTERFACE);
70        for (ResolveInfo resolveInfo : mPackageManager.queryIntentServices(intent, 0)) {
71            ServiceInfo serviceInfo = resolveInfo.serviceInfo;
72            if (serviceInfo != null) {
73                int sourceIndex = findProvider(serviceInfo.packageName, serviceInfo.name);
74                if (sourceIndex < 0) {
75                    RegisteredMediaRouteProvider provider =
76                            new RegisteredMediaRouteProvider(mContext,
77                            new ComponentName(serviceInfo.packageName, serviceInfo.name));
78                    provider.start();
79                    mProviders.add(targetIndex++, provider);
80                    mRouter.addProvider(provider);
81                } else if (sourceIndex >= targetIndex) {
82                    RegisteredMediaRouteProvider provider = mProviders.get(sourceIndex);
83                    provider.rebindIfDisconnected();
84                    Collections.swap(mProviders, sourceIndex, targetIndex++);
85                }
86            }
87        }
88
89        // Remove providers for missing services.
90        if (targetIndex < mProviders.size()) {
91            for (int i = mProviders.size() - 1; i >= targetIndex; i--) {
92                RegisteredMediaRouteProvider provider = mProviders.get(i);
93                mRouter.removeProvider(provider);
94                mProviders.remove(provider);
95                provider.stop();
96            }
97        }
98    }
99
100    private int findProvider(String packageName, String className) {
101        int count = mProviders.size();
102        for (int i = 0; i < count; i++) {
103            RegisteredMediaRouteProvider provider = mProviders.get(i);
104            if (provider.hasComponentName(packageName, className)) {
105                return i;
106            }
107        }
108        return -1;
109    }
110}
111