RemoteCallbackList 是 Android 提供的一种用于在远程服务端和客户端之间进行回调的机制。它主要用于处理服务端主动推送的消息,而不需要客户端主动请求。要实现 RemoteCallbackList,你需要遵循以下步骤:
首先,你需要定义一个接口,用于接收服务端推送的消息。例如:
public interface RemoteCallback {
void onMessageReceived(String message);
}
在你的服务端代码中,创建一个 RemoteCallbackList 对象来存储注册的回调接口实例。例如:
private RemoteCallbackList<RemoteCallback> mCallbacks = new RemoteCallbackList<>();
当客户端连接到服务端时,你需要将回调接口实例注册到 RemoteCallbackList 对象中。例如:
public void registerCallback(RemoteCallback callback) {
mCallbacks.register(callback);
}
当客户端断开与服务端的连接时,你需要将回调接口实例从 RemoteCallbackList 对象中注销。例如:
public void unregisterCallback(RemoteCallback callback) {
mCallbacks.unregister(callback);
}
当你需要向客户端推送消息时,遍历 RemoteCallbackList 对象中的所有回调接口实例,并调用它们的 onMessageReceived 方法。例如:
private void sendMessageToClients(String message) {
for (int i = 0; i < mCallbacks.beginBroadcast(); i++) {
RemoteCallback callback = mCallbacks.getBroadcastItem(i);
if (callback != null) {
callback.onMessageReceived(message);
}
}
mCallbacks.finishBroadcast();
}
在客户端代码中,实现 RemoteCallback 接口,并重写 onMessageReceived 方法以处理接收到的消息。例如:
public class MyServiceConnection implements ServiceConnection {
private IMyService mService;
@Override
public void onServiceConnected(ComponentName className, IBinder service) {
mService = IMyService.Stub.asInterface(service);
try {
mService.registerCallback(new RemoteCallback() {
@Override
public void onMessageReceived(String message) {
// 处理接收到的消息
}
});
} catch (RemoteException e) {
e.printStackTrace();
}
}
@Override
public void onServiceDisconnected(ComponentName arg0) {
if (mService != null) {
try {
mService.unregisterCallback(new RemoteCallback() {
@Override
public void onMessageReceived(String message) {
// 处理接收到的消息
}
});
} catch (RemoteException e) {
e.printStackTrace();
}
mService = null;
}
}
}
在客户端代码中,绑定到服务端并实现 MyServiceConnection 接口。例如:
private MyServiceConnection mConnection = new MyServiceConnection();
private boolean mIsBound = false;
private ServiceConnection bindService() {
Intent intent = new Intent();
intent.setClass(this, MyService.class);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
return mConnection;
}
private void unbindService() {
if (mIsBound) {
unbindService(mConnection);
mIsBound = false;
}
}
通过以上步骤,你可以在 Android 中实现 RemoteCallbackList,以便在服务端和客户端之间进行回调。