Android：如何在服务中拥有本地广播接收器

Question

我有一个服务，我想要一个本地广播接收器。我想从活动中获得一个价值到我的服务 onCreate。

注意：我可以使用意图在 onStartCommand() 中从活动中获取一个值到我的服务。但在这里，我想从服务的 onCreate 中的活动中获得价值。

以下是我的服务文件：

    public class MediaServiceSimha extends Service {

        private MediaPlayer player;
        String musicpath;
        private ResponseReceiver receiver;

        public MediaServiceSimha() {}

        @Override
        public IBinder onBind(Intent intent) {
            return null;
        }

        @Override
        public void onDestroy() {
            LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
            localBroadcastManager.unregisterReceiver(receiver);
            super.onDestroy();
        }

        @Override
        public boolean onUnbind(Intent intent) {
            return super.onUnbind(intent);
        }

        @
        Override
        public int onStartCommand(Intent intent, int flags, int startId) {
            player.start();
            return super.onStartCommand(intent, flags, startId);
        }

        @Override
        public void onCreate() {
            super.onCreate();
            IntentFilter broadcastFilter = new IntentFilter("com.example.myintentserviceapp.intent_service.ALL_DONE");
            receiver = new ResponseReceiver();
            LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
            localBroadcastManager.registerReceiver(receiver, broadcastFilter);
        }

        public class ResponseReceiver extends BroadcastReceiver {

            @Override
            public void onReceive(Context context, Intent intent) {
                musicpath = intent.getStringExtra("musicpath");
            }
        }
    }

以下是我想要传递一个名为 musicpath 的值的活动文件

public class ServiceTest extends AppCompatActivity {
    Intent intent;

    public static final String TEXT_INPUT = "inText";
    //MediaServiceSimha mediaServiceSimha;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        L.m("activity_oncreate_starting");
        setContentView(R.layout.activity_service_test);
        intent= new Intent(this,MediaServiceSimha.class);

        startService(intent);

        Intent broadcastIntent = new Intent();
        broadcastIntent.setAction("com.example.myintentserviceapp.intent_service.ALL_DONE");
        broadcastIntent.putExtra("musicpath", "/storage/emulated/0/Download/1.mp3");
        LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
        localBroadcastManager.sendBroadcast(broadcastIntent)
    }


}

运行后提示musicpath值为null。

怎么做？

Answer 1

我的目标是将变量值直接传递给服务类中的 oncreate。

我尝试了 LocalBroadcast 的接收器以及 onbindservices - onServiceConnected

我发现它们都只会被执行，直到 oncreate -> onbind/onstartcommand 在服务中执行。

所以剩下的唯一选项是 onstartcommand()

因此，当我们使用意图传递值时，它们可以立即在 onstartcommand 中使用。

Answer 2

当您调用启动服务时，并不意味着它会立即调用，因此请等待服务的 oncreate，每当您的服务启动时，您可以向您的活动发送回调，然后您可以向您的服务广播值

       public service callback()  // callback from service started
        {
        Intent broadcastIntent = new Intent();
                broadcastIntent.setAction("com.example.myintentserviceapp.intent_service.ALL_DONE");
                broadcastIntent.putExtra("musicpath", "/storage/emulated/0/Download/1.mp3");
                LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
                localBroadcastManager.sendBroadcast(broadcastIntent)
        } 


      public class MediaServiceSimha extends Service {
      @Override
            public void onCreate() {
                super.onCreate();
                IntentFilter broadcastFilter = new IntentFilter("com.example.myintentserviceapp.intent_service.ALL_DONE");
                receiver = new ResponseReceiver();
                LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
                localBroadcastManager.registerReceiver(receiver, broadcastFilter);
              sendCallback(); // using interface or broadcast receiver to send callback to activity
            }

}