Service 通过 BroadcastReceiver与Activity 进行通信_broadcastreceiver和activity通信-优快云博客

本文介绍了一个Android应用中如何通过IntentService实现文件下载，并使用BroadcastReceiver通知主线程Activity文件下载完成的状态。代码示例展示了如何注册和注销广播接收器，以及如何在服务中执行下载任务。

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Activity 类代码

public class MainActivity extends AppCompatActivity {
    IntentFilter intentFilter;
    private BroadcastReceiver intentRecevicer = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Toast.makeText(getBaseContext(),"onReceive => File download!",Toast.LENGTH_SHORT).show();
        }
    };
    @Override
    protected void onResume() {
        super.onResume();
        intentFilter = new IntentFilter();
        intentFilter.addAction("FILE_DOWNLOAD_ACTION");
        registerReceiver(intentRecevicer,intentFilter);
    }
    @Override
    protected void onPause() {
        super.onPause();
        unregisterReceiver(intentRecevicer);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    public void startService(View view){
        Log.i("Service","startService");
        startService(new Intent(this,MyIntentService.class));
    }
    public void stopService(View view){
        Log.i("Service","stopService");

    }
}

Service类代码

public class MyIntentService extends IntentService {

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.i("Service","MyIntentService Destroy");
    }
    public MyIntentService() {
        super("MyIntentServiceName");
    }
    @Override
    protected void onHandleIntent(Intent intent) {
        try{
            int result = DownloadFile(new URL("http://www.x-motion.com/somefile.pdf"));

            Intent broadcastIntent = new Intent();
            broadcastIntent.setAction("FILE_DOWNLOAD_ACTION");
            getBaseContext().sendBroadcast(broadcastIntent);

        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
    }
    private int DownloadFile(URL url){
        try{
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return 100;
    }
}