在其他时间调用AsyncTask obj的问题 - Android

时间：2011-04-15 11:48:36

标签： android android-asynctask

在我的Activity类中实现了UINotifier，用于在调用TimerTask对象时通知Activity类。在我的doInBackground（）中，我只调用位于ASyncTask类（connectTask）中的函数。执行onPostExecute，最后，我调用位于Activity类中的方法“ReConnect（）”。 代码及其流程是：

// OF Interface UINotifier
@Override
public void notifyUI() {
    Log.i(TAG, "GOT MESSAGE FROM MonitorConnection");
    monitorTimer.cancel();
    Log.i(TAG, "Preparing to Start");
    PrepareToStartToConnect();
    //publishProgress(4);
    int status = 1;
    if (status == 1 || status == 2)
        ReConnect();
}

// Called on "Connect" button
private void ConnectClicked() {
    Log.i(TAG, "Inside Connectclicked");
    if (isConnectEligeble()) {
        Log.i(TAG, "isConnectionEligible = true");
        currentState= CONNECTING;
        connectTask = new ConnectTask();
        Log.i(TAG, "CReated ins of ConnectTask");
        connectTask.execute("");
    }
}

private void ReConnect() {
    connectTask = null;

    if (HttpUtilities.checkInternetConnection()) {
        Log.i(TAG, "ABOUT TO RE-CONNECT");
        ConnectClicked();
    } else {
        Log.i(TAG, "No Interne Mesage");
        mMessage.setText(R.string.NO_INERNET);
    }
    return;
}

private void PrepareToStartToConnect() {
    monitorTimer = null;
    monitorConn = null;
    // Make all vars, objects to null   
}

// Start TimerTask & Timer object
private void StartTimer() {
    Log.i(TAG, "Into Start Timer");
    monitorConn = new MonitorConnection(this);   // new MonitorConnection(connectTask);
    monitorTimer = new Timer();
    monitorTimer.schedule(monitorConn, 0, 30000);
}


/**
 * ConnectTask  AsyncTask class that handles all activities to get connected to the server
 */
private class ConnectTask extends AsyncTask<String, Integer, Boolean> implements UINotifier {
    private ProgressDialog dialog = null;
    private UServer us = null;
    private VPNServer vs = null;
    private ConfigData cd = null;
    String serverHost = "", errorMsg = ""; 
    private int status = -1; // 0 Connected  1 = ReConnect  2 = Failed to Connect

    public ConnectTask() {
        dialog  = new ProgressDialog(StartUltimate.this);
        us  = servers.get(selectedRowIndex);
        vs = us.getVpnServer(selectedProtocol, selectedPort);
        serverHost = us.getServerHost();
    }

    private void disposeAll() {
        // Dispose all objs
    }

    @Override
    protected void onPostExecute(Boolean result) {
        super.onPostExecute(result);
        Log.i(TAG, "Into onPostExecute()");
        if (result == false)
            mMessage.setText(errorMsg);
        else
            mMessage.setText("");
        dialog.dismiss();
        // Clean up all variables of the object
        disposeAll();
        Log.i(TAG, "FINISHED onPostExecute()");
        // Go out of AsyncTask and have control to other method of Activity class
        StartTimer();
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        selectedServerHost = serverHost.substring(0, serverHost.indexOf('.'));
        dialog.setCancelable(false);
        dialog.setIcon(R.drawable.icon);
        dialog.setTitle("Progessing...");
        dialog.setMessage(String.valueOf(R.string.ui_activity_authenticating));
        dialog.show();
    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        super.onProgressUpdate(values);
        // Set all updates to UI
        return;
    }

    @Override
    protected Boolean doInBackground(String... params) {
        Log.i(TAG, "Into doBackground...");
        ......
        Log.i(TAG, "Starting Connect.....");
        StartConnect();

        return true;
    }

    @Override
    public void notifyUI() {
        Log.i(TAG, "GOT MESSAGE FROM MonitorConnection");
        monitorTimer.cancel();
        Log.i(TAG, "Preparing to Start");
        PrepareToStartToConnect();
        publishProgress(4);
        status = 1;
        if (status == 1 || status == 2)
            ReConnect();
    }


    private void StartConnect() {
        // This is empty right now      
    }
}   // END OF ConnectTask class

调用StartTimer，MonitorThread通知Activity类，并调用ReConnect调用ConnectClicked。在ConnectClicked中， connectTask = new ConnectTask（）;是我得到此异常和日志的地方：

04-15 17:09:07.501: INFO/Ultimate VPN:(364): Starting Connect.....
04-15 17:09:07.501: INFO/Ultimate VPN:(364): Into onPostExecute()
04-15 17:09:07.501: INFO/Ultimate VPN:(364): FINISHED onPostExecute()
04-15 17:09:07.501: INFO/Ultimate VPN:(364): Into Start Timer
04-15 17:09:07.542: INFO/MON CONN(364): Into StartMonitor
04-15 17:09:07.542: INFO/MON CONN(364): Into checkConnection
04-15 17:09:07.671: WARN/InputManagerService(69): Window already focused, ignoring focus gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@4073b170
04-15 17:09:08.252: INFO/System.out(364): MonitorConnection : Notifing the GUI
04-15 17:09:08.262: INFO/Ultimate VPN:(364): GOT MESSAGE FROM MonitorConnection
04-15 17:09:08.262: INFO/Ultimate VPN:(364): Preparing to Start
04-15 17:09:18.322: INFO/Ultimate VPN:(364): ABOUT TO RE-CONNECT
04-15 17:09:18.322: INFO/Ultimate VPN:(364): Inside Connectclicked
04-15 17:09:18.322: INFO/Ultimate VPN:(364): isConnectionEligible = true
04-15 17:09:18.331: WARN/dalvikvm(364): threadid=11: thread exiting with uncaught exception (group=0x40015560)
04-15 17:09:18.351: ERROR/AndroidRuntime(364): FATAL EXCEPTION: Timer-0
04-15 17:09:18.351: ERROR/AndroidRuntime(364): java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at android.os.Handler.<init>(Handler.java:121)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at android.app.Dialog.<init>(Dialog.java:101)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at android.app.AlertDialog.<init>(AlertDialog.java:63)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at android.app.ProgressDialog.<init>(ProgressDialog.java:80)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at android.app.ProgressDialog.<init>(ProgressDialog.java:76)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at orange.android.vpn.StartUltimate$ConnectTask.<init>(StartUltimate.java:386)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at orange.android.vpn.StartUltimate.ConnectClicked(StartUltimate.java:324)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at orange.android.vpn.StartUltimate.ReConnect(StartUltimate.java:340)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at orange.android.vpn.StartUltimate.notifyUI(StartUltimate.java:316)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at orange.android.vpn.MonitorConnection.setConnected(MonitorConnection.java:43)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at orange.android.vpn.MonitorConnection.checkConnection(MonitorConnection.java:69)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at orange.android.vpn.MonitorConnection.StartMonitor(MonitorConnection.java:61)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at orange.android.vpn.MonitorConnection.run(MonitorConnection.java:52)
04-15 17:09:18.351: ERROR/AndroidRuntime(364):     at java.util.Timer$TimerImpl.run(Timer.java:284)
04-15 17:09:18.382: WARN/ActivityManager(69):   Force finishing activity orange.android.vpn/.StartUltimate

知道我为什么会收到这个错误吗？我该如何解决？我尝试在ConnectTask类而不是Activity类中处理UINotifier。但是在StartConnect（）之后立即调用onPost，尽管已经添加了StartTimer并且该线程已经在运行。然后doInBackground也停止了，所以我用这种方式管理它。但是我得到错误的方式。在其他情况下，我得到...... Looper ....例外。

非常感谢任何帮助。

由于

1 个答案:

答案 0 :(得分：1)

我会摆脱UINotifier（自定义实现），并使用Android中现成的Handler机制来通知用户界面。

有关类似的实施，请参阅How to get XML using AsyncTask and Timer?。

另外，请参阅此处的无痛线程文章：http://developer.android.com/resources/articles/painless-threading.html，了解有关线程（和处理程序）的更多信息

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