在我正在开发的应用程序中，当我触摸设备的屏幕时，我连接到服务器并使用AsyncTask显示忙碌的指示器，并且在此步骤中我没有 问题。但是当我连接并按下家庭按钮时，应用程序进入onPause＆＃34;然后我再次看到应用程序＆＃34; onResume＆＃34;并触摸屏幕 再次连接到服务器，我收到以下发布的logCat错误。
注意：在onPause我urnRegister WiFi接收器，我断开与服务器的连接。 logCat输出显示AsyncTask
的调用回调序列我不知道为什么我收到IllegalArgumentException，我读了一些关于它的帖子，我测试了名为＆＃34; client＆＃34;的对象，它永远不会为空
logcat的：
03-09 14:26:13.413: D/MainActivity(17065): @MQTTAsynchTask(): constructor called
03-09 14:26:13.413: D/MainActivity(17065): @MQTTAsynchTask(): client is not null
03-09 14:26:13.413: D/MainActivity(17065): @MQTTAsynchTask(): onPreExecute().
03-09 14:26:13.422: D/MainActivity(17065): @MQTTAsynchTask(): doInBackground().
03-09 14:26:13.433: E/AndroidRuntime(17065): FATAL EXCEPTION: pool-1-thread-1
03-09 14:26:13.433: E/AndroidRuntime(17065): Process: com.example.mqtt_designlayout_02, PID: 17065
03-09 14:26:13.433: E/AndroidRuntime(17065): java.lang.IllegalArgumentException: Invalid ClientHandle
03-09 14:26:13.433: E/AndroidRuntime(17065): at org.eclipse.paho.android.service.MqttService.getConnection(MqttService.java:552)
03-09 14:26:13.433: E/AndroidRuntime(17065): at org.eclipse.paho.android.service.MqttService.connect(MqttService.java:318)
03-09 14:26:13.433: E/AndroidRuntime(17065): at org.eclipse.paho.android.service.MqttAndroidClient.doConnect(MqttAndroidClient.java:427)
03-09 14:26:13.433: E/AndroidRuntime(17065): at org.eclipse.paho.android.service.MqttAndroidClient.access$2(MqttAndroidClient.java:417)
03-09 14:26:13.433: E/AndroidRuntime(17065): at org.eclipse.paho.android.service.MqttAndroidClient$1.run(MqttAndroidClient.java:395)
03-09 14:26:13.433: E/AndroidRuntime(17065): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
03-09 14:26:13.433: E/AndroidRuntime(17065): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
03-09 14:26:13.433: E/AndroidRuntime(17065): at java.lang.Thread.run(Thread.java:818)
AsynchTask
public MQTTAsynchTask(Context contex, MqttAndroidClient client, MqttConnectOptions opts) {
// TODO Auto-generated constructor stub
Log.d(TAG, "@MQTTAsynchTask(): constructor called");
this.context = contex;
this.MQTTAndroidClient = client;
if (client != null) {
Log.d(TAG, "@MQTTAsynchTask(): client is not null");
}
this.opts = opts;
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
Log.d(TAG, "@MQTTAsynchTask(): onPreExecute().");
dialog = new Dialog(this.context);
dialog.setCancelable(false);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.progressdialog);
progressBar = (ProgressBar) dialog.findViewById(R.id.progressBar1);
dialog.show();
}
@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
Log.d(TAG, "@MQTTAsynchTask(): doInBackground().");
do {
try {
this.MQTTAndroidClient.connect(this.opts, this.context, synchCONNCallBack);
} catch (MqttSecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (MqttException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
Thread.sleep(MQTT_BROKER_TIME_OUT);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
this.totalTimeOut += MQTT_BROKER_TIME_OUT;
} while ( (!this.isCancelled()) && (this.MQTTAndroidClient != null) && (!this.MQTTAndroidClient.isConnected()) && (this.totalTimeOut <= (10 * MQTT_BROKER_TIME_OUT)) );
return null;
}
的onPause ：
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
Log.w(TAG, "@onPause()");
this.onPauseCalled = true;
if (reconnectTimerCurrentlyActive) {
reconnectTimerCurrentlyActive = false;
reconnectTimer.cancel();
reconnectTimer.purge();
Log.v(TAG, "reconnect timer set to 'false', and reconnectTimer is cancelled");
}
if (this.MQTTAsynch != null) {
Log.d(TAG, "asynchTask object was initilised");
if (this.MQTTAsynch.getStatus() == AsyncTask.Status.PENDING) {
Log.d(TAG, "AsynchTask has not started yet.");
boolean cancelledSuccessully = this.MQTTAsynch.cancel(true);
if (cancelledSuccessully) {
Log.d(TAG, "AsynchTask is cancelled successfully.");
} else {
Log.d(TAG, "AsynchTask failed to cancell");
}
}
if (this.MQTTAsynch.getStatus() == AsyncTask.Status.RUNNING) {
Log.d(TAG, "AsynchTask still running doing work in the backgroung thread, and it will be intrrupted");
boolean cancelledSuccessully = this.MQTTAsynch.cancel(true);
if (cancelledSuccessully) {
Log.d(TAG, "AsynchTask is cancelled successfully.");
} else {
Log.d(TAG, "AsynchTask failed to cancell");
}
}
if (this.MQTTAsynch.getStatus() == AsyncTask.Status.FINISHED) {
Log.d(TAG, "AsynchTask has finished its work.");
}
} else {
Log.d(TAG, "asynchTask object was not initilised. this.MQTTAsynch == null");
}
if ( (this.subActivityReturned) || (this.isConnectCalled) ) {
MQTT_Disconnect_Module();
}
if (MQTTPrimaryReceiverRegistered) {
unregisterReceiver(MQTTPrimaryReceiver);
Log.v(TAG, "BroadCastReceiver (MQTTPrimaryReceiver) unregistered");
MQTTPrimaryReceiverRegistered = false;
}
}
答案 0 :(得分：10)
我认为首先要学习的是完全阅读ErrorLogs并理解它。 stacktrace 的第一行表示
03-09 14:26:13.433: E/AndroidRuntime(17065): java.lang.IllegalArgumentException: Invalid ClientHandle
03-09 14:26:13.433: E/AndroidRuntime(17065): at org.eclipse.paho.android.service.MqttService.getConnection(MqttService.java:552)
即错误在方法MqttService中的getConnection()类中开始。方法getConnection()正在抛出IllegalArgumentException而不是AsyncTask。恰好从AsyncTask内部调用它。此外，变量 ClientHandle 不是Android API的一部分，它是MqttService的一部分。该变量实际上是无效的，并且导致异常。
如果您无法弄清楚变量MqttService无效的原因，您也可以共享ClientHandle课程。也许这里的人可以帮助你，但是根据所提供的信息，这是我能回答的问题。希望这会有所帮助。