Toast消息在Android的Java Websocket服务器接收到消息时未被创建。

huangapple
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英文:

Toast Message is not created when message received at Java Websocket server in Android

问题

我正在尝试使用 这个 库创建基本的WebSocket服务器。
当接收到消息时，我想要显示一个提示消息。
在下面的onMessage()函数中，我已经实现了这一点。但是没有显示提示消息。

但是接收到的消息会打印在控制台上。

  1. WebSocketServer ws = new WebSocketServer(new InetSocketAddress(3000)) {
  3.     @Override
  4.     public void onOpen(WebSocket conn, ClientHandshake handshake) {
  5.         conn.send("Hello world");
  6.     }
  8.     @Override
  9.     public void onClose(WebSocket conn, int code, String reason, boolean remote) {
  11.     }
  13.     @Override
  14.     public void onMessage(WebSocket conn, String message) {
  15.         System.out.println("Received: " + message);
  16.         Toast.makeText(MainActivity.this, "Received: " + message, Toast.LENGTH_SHORT).show();
  17.     }
  19.     @Override
  20.     public void onError(WebSocket conn, Exception ex) {
  22.     }
  24.     @Override
  25.     public void onStart() {
  27.     }
  28. };
  29. ws.start();
英文:

I am trying to create basic WebSocket server with this library.
I want to make a toast message when a message is received.
In onMessage() function below I have implemented that. But no toast message is happening.

But Received message is printed on console.

  1.         WebSocketServer ws = new WebSocketServer(new InetSocketAddress(3000)) {
  3.         @Override
  4.         public void onOpen(WebSocket conn, ClientHandshake handshake) {
  5.             conn.send("Hello world");
  6.         }
  8.         @Override
  9.         public void onClose(WebSocket conn, int code, String reason, boolean remote) {
  11.         }
  13.         @Override
  14.         public void onMessage(WebSocket conn, String message) {
  15.             System.out.println("Recieved: "+message);
  16.             Toast.makeText(MainActivity.this, "Recieved: " + message, Toast.LENGTH_SHORT).show();
  17.         }
  19.         @Override
  20.         public void onError(WebSocket conn, Exception ex) {
  22.         }
  24.         @Override
  25.         public void onStart() {
  27.         }
  28.     };
  29.     ws.start();
  30. }

答案1

得分: 0

我认为你需要切换到UI线程来显示Toast。

你可以尝试使用Handler：

  1. new Handler(Looper.getMainLooper()).post(new Runnable() {
  2.     public void run() {
  3.         Toast.makeText(MainActivity.this, "接收到消息：" + message, Toast.LENGTH_SHORT).show();
  4.     }
  5. });

或者调用runOnUiThread：

  1. runOnUiThread(new Runnable() {
  2.     @Override
  3.     public void run() {
  4.         Toast.makeText(MainActivity.this, "接收到消息：" + message, Toast.LENGTH_SHORT).show();
  5.     }
  6. });

或者广播消息：

  1. @Override
  2. public void onMessage(WebSocket conn, String message) {
  3.     System.out.println("接收到消息：" + message);
  5.     Intent intent = new Intent("msgReceived");
  6.     intent.putExtra("message", message);
  7.     LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
  8. }

然后在你的Activity中注册一个BroadcastReceiver：

  1. private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
  2.     @Override
  3.     public void onReceive(Context context, Intent intent) {
  4.         String message = intent.getExtras().getString("message");
  5.         Toast.makeText(MainActivity.this, "接收到消息：" + message, Toast.LENGTH_SHORT).show();
  6.     }
  7. };
  9. @Override
  10. protected void onStart() {
  11.     super.onStart();
  12.     LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver, new IntentFilter("msgReceived"));
  13. }
  15. @Override
  16. protected void onStop() {
  17.     LocalBroadcastManager.getInstance(this).unregisterReceiver(mMessageReceiver);
  18.     super.onStop();
  19. }
英文:

I think you have to switch to the UI thread to show the Toast.

You can try using a Handler:

  1. new Handler(Looper.getMainLooper()).post(new Runnable() {
  2.     public void run() {
  3.         Toast.makeText(MainActivity.this, "Received: " + message, Toast.LENGTH_SHORT).show();
  4.     }
  5. });

Or calling runOnUiThread:

  1. runOnUiThread(new Runnable() {
  2.     @Override
  3.     public void run() {
  4.         Toast.makeText(MainActivity.this, "Received: " + message, Toast.LENGTH_SHORT).show();
  5.     }
  6. });

Or broadcasting the message:

  1. @Override
  2. public void onMessage(WebSocket conn, String message) {
  3.     System.out.println("Recieved: "+message);
  5.     Intent intent = new Intent("msgReceived");
  6.     intent.putExtra("message", message);
  7.     LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
  8. }

And registering a BroadcastReceiver in your Activity:

  1. private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
  2.     @Override
  3.     public void onReceive(Context context, Intent intent) {
  4.         String message = intent.getExtras().getString("message");
  5.         Toast.makeText(MainActivity.this, "Received: " + message, Toast.LENGTH_SHORT).show();
  6.     }
  7. };
  9. @Override
  10. protected void onStart() {
  11.     super.onStart();
  12.     LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver, new IntentFilter("msgReceived"));
  14. @Override
  15. protected void onStop() {
  16.     LocalBroadcastManager.getInstance(this).unregisterReceiver(mMessageReceiver);
  17.     super.onStop();
  18. }

huangapple
  • 本文由 发表于 2020年9月20日 05:09:41
  • 转载请务必保留本文链接：https://go.coder-hub.com/63973393.html
  • android
  • android-studio
  • java
  • java-websocket
  • websocket
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