[英]Send Data from Service To Activity Android
我正在構建一個使用服務進行播放的音樂播放器。 我有一個Activity UI來控制(播放,暫停,下一步......)服務。 我想在按下下一個或上一個按鈕時從我的服務更新UI。 我想過傳遞一個整數值。 這是我的代碼:
我用過信使進行交流。 我服務中的代碼如下所示:
enum Event {
NextSongChanged, CurrentPlayingSong
};
public synchronized void registerHandler(Messenger m) {
clients.add(m);
}
private void emit(Event e) {
for (Messenger m : clients) {
try {
m.send(Message.obtain(null, e.ordinal()));
} catch (RemoteException exception) {
/* The client must've died */
clients.remove(m);
}
}
}
我打電話的方法點擊下一步按鈕:
public synchronized void playnext() {
reset();
if(songIndex < (songsList.size() - 1)) {
songIndex += 1;
playSong(songIndex);
} else {
songIndex = 0;
playSong(songIndex);
}
emit(Event.NextSongChanged);
}
一旦我觸發NextSongChanged事件,我想將“songIndex”變量傳遞給我的活動。 有關如何實現這一點的任何想法?
我的活動代碼來處理事件:
private Messenger playerMessenger = new Messenger(new Handler() {
@Override
public void handleMessage(Message msg) {
switch (MyService.Event.values()[msg.what]) {
case NextSongChanged:
//String songTitle = songsList.get(currentSongIndex+1).get("songTitle");
//currentSongIndex += 1;
//songTitleLabel.setText(songTitle);
//updatePlaying();
break;
case CurrentPlayingSong:
break;
}
}
});
示例代碼希望將有助於其他人
1.設置Handler(接收消息)和Messenger(進行通信) MainActivity.java
Messenger msgService;
boolean isBound;
ServiceConnection connection = new ServiceConnection() {
@Override
public void onServiceDisconnected(ComponentName name) { isBound = false; }
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
isBound = true;
msgService = new Messenger(service);
}
};
public void sendMessage(View view) {
if (isBound) {
try {
Message message = Message.obtain(null, MessangerService.MESSAGE, 1, 1);
message.replyTo = replyMessenger;
Bundle bundle = new Bundle();
bundle.putString("rec", "Hi, you hear me");
message.setData(bundle);
msgService.send(message); //sending message to service
} catch (RemoteException e) {
e.printStackTrace();
}
}
}
//setting reply messenger and handler
Messenger replyMessenger = new Messenger(new HandlerReplyMsg());
class HandlerReplyMsg extends Handler {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
String recdMessage = msg.obj.toString(); //msg received from service
toast(recdMessage);
}
}
2.設置服務類MessengerService.java
Messenger replyMessanger;
final static int MESSAGE = 1;
class IncomingHandler extends Handler {
@Override
public void handleMessage(Message msg) {
if (msg.what == MESSAGE) {
Bundle bundle = msg.getData();
toast(bundle.getString("rec"));//message received
replyMessanger = msg.replyTo; //init reply messenger
doSomething();
}
}
}
private void doSomething() {
// do stuff
if (replyMessanger != null)
try {
Message message = new Message();
message.obj = "Yes loud and clear";
replyMessanger.send(message);//replying / sending msg to activity
} catch (RemoteException e) {
e.printStackTrace();
}
}
Messenger messenger = new Messenger(new IncomingHandler());
@Override
public IBinder onBind(Intent intent) {
return messenger.getBinder();
}
確保您在manifest
聲明了Service,並在活動中聲明了binding/unbinding
服務。
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