动态改变service内容添加下载信息

最近的项目中，有一个需求是 【后台下载+多线程+Notificaton进度条】的应用。要求有一个Service做下载服务，Notification中显示一进度条，进度条由Service来更新。
花了个把小时在网上找代码，没有一个完美的方案，最后根据片段信息，自己实现了。贴出来分享一下。

思路：

• 1. 有一个提供队列下载的Service
• 2. 该Service可以绑定，绑定的时候返回本身实例
• 3. 该Service提供方法给绑定了该Service的Activity，Activity可以调用Service的提供的方法，给Service添加队列
• 4. 该Service提供了当前下载队列的信息，信息包括下载的名称，下载进度，Activity通过接口读取队列信息用于操作，如：取消

实现：

1. 队列类

1. public classDownLoadQueue{
2.  
3.     public int id; //队列id ， 该id标识了一条下载线程和Notification
4.  
5.     public Stringname; // 队列名称，用于显示在Notification中
6.  
7.      public int progress = 0; //进度，一个0-100之前的整数，标识百分比
8.  
9.      public boolean isCancel = fale; //是否已经取消，该开关用于取消下载
10.  

2. Service类：

1.   public classDownloadService extends Service{
2.  
3.            private MapdownLoadQueue; //下载队列，格式：
4.  
5.              private BinderserviceBinder = new DownLoadServiceBinder();
6.  
7.                // Activity绑定后，会自动条用这个方法
8.                @Override
9.                public IBinderonBind(Intentintent)
10.                {
11.                     Log.d("DownloadService", "onBind");
12.                     return serviceBinder;
13.                }
14.  
15.                ....
16.  
17.                private void startDownLoad(DownLoadQueuequeue){
18.                     new Thread(){
19.                          public void run(){
20.                               //进行下载工作，这里需要更新downLoadQueue中对应的queue的进度信息
21.                               //使用Handler更新notification信息
22.                               ....
23.                          }
24.  
25.                     }.start();
26.                }
27.  
28.                public void addQueue(DownLoadQueuequeue){
29.                     this.downLoadQueue.add(queue.id,queue);
30.                     this.startDownLoad(queue);
31.                }
32.  
33.                public MapgetQueueList(){
34.                     return this.downLoadQueue;
35.                }
36.  
37.              public classpublic DownLoadServiceBinder extends Binder{
38.                   public DownloadServicegetService(){
39.                          return DownloadService.this;
40.                     }
41.              }

3. Activity类：

1. public classDownLoadActivity{
2.           private Handlerhandler = new Handler();
3.           private DownloadServicedownLoadService;
4.           private ServiceConnectionserviceConnection = new ServiceConnection()
5.           {
6.                // 连接服务失败后，该方法被调用
7.                @Override
8.                public void onServiceDisconnected(ComponentNamename)
9.                {
10.                     downLoadService = null;
11.                     Toast.makeText(DownLoadActivity.this, "Service Failed.", Toast.LENGTH_LONG).show();
12.                }
13.                // 成功连接服务后，该方法被调用。在该方法中可以获得downLoadService对象
14.                @Override
15.                public void onServiceConnected(ComponentNamename, IBinderservice)
16.                {
17.                     // 获得downLoadService对象
18.                     downLoadService = ((DownLoadService.DownLoadServiceBinder) service).getService();
19.                     Toast.makeText(DownLoadActivity.this, "Service Connected.", Toast.LENGTH_LONG).show();
20.                }
21.           };
22.  
23.           @Override
24.           public void onCreate(BundlesavedInstanceState){
25.                super.onCreate(savedInstanceState);
26.                IntentserviceIntent = new Intent(DownLoadActivity.this,DownloadService.class);
27.                bindService(serviceIntent, serviceConnection, Context.BIND_AUTO_CREATE);
28.                startService(serviceIntent);
29.                .....
30.           }
31.  
32.           private void startDownLoad(){
33.                DownLoadQueuequeue = new DownLoadQueue();
34.                queue.id = 1;
35.                queue.name = "愤怒的小鸟"
36.                ...
37.                downLoadService.addDownLoad(queue);
38.                ....
39.           }
40.  
41.           @Override
42.           public void onDestroy(){
43.                super.onDestroy();
44.                unbindService(new Intent(DownLoadActivity.this,DownloadService.class));
45.           }

4. 在Service中更新Notification时，不能过于频繁，否则会造成卡机。notification使用RemoteView来自定义Notification，加入进度条加入各种说明文字，等等。

以上文字只是简单的提及了一些思路。在项目中已经实现。下次修改完善后贴上来分享。希望能够将该功能做成一个独立的Service供大家在项目中嵌入使用