java - 使用Timer调用AsyncTask类

Question

我正在尝试使用一个计时器来按固定的时间表调用“AysncTask”类。这个计时器/类与 GUI 或其 elements 没有任何关系。当调用不带计时器的类时，它可以工作，但是使用计时器时，我会收到这些错误:

01-04 08:39:39.074: E/AndroidRuntime(394): FATAL EXCEPTION: main
01-04 08:39:39.074: E/AndroidRuntime(394): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.projecta/com.example.projecta.MainActivity}: java.lang.RuntimeException: Only one Looper may be created per thread
01-04 08:39:39.074: E/AndroidRuntime(394):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
01-04 08:39:39.074: E/AndroidRuntime(394):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
01-04 08:39:39.074: E/AndroidRuntime(394):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
01-04 08:39:39.074: E/AndroidRuntime(394):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
01-04 08:39:39.074: E/AndroidRuntime(394):  at android.os.Handler.dispatchMessage(Handler.java:99)
01-04 08:39:39.074: E/AndroidRuntime(394):  at android.os.Looper.loop(Looper.java:123)
01-04 08:39:39.074: E/AndroidRuntime(394):  at android.app.ActivityThread.main(ActivityThread.java:4627)
01-04 08:39:39.074: E/AndroidRuntime(394):  at java.lang.reflect.Method.invokeNative(Native Method)
01-04 08:39:39.074: E/AndroidRuntime(394):  at java.lang.reflect.Method.invoke(Method.java:521)
01-04 08:39:39.074: E/AndroidRuntime(394):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
01-04 08:39:39.074: E/AndroidRuntime(394):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
01-04 08:39:39.074: E/AndroidRuntime(394):  at dalvik.system.NativeStart.main(Native Method)
01-04 08:39:39.074: E/AndroidRuntime(394): Caused by: java.lang.RuntimeException: Only one Looper may be created per thread
01-04 08:39:39.074: E/AndroidRuntime(394):  at android.os.Looper.prepare(Looper.java:73)
01-04 08:39:39.074: E/AndroidRuntime(394):  at com.example.projecta.MainActivity.onCreate(MainActivity.java:43)
01-04 08:39:39.074: E/AndroidRuntime(394):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-04 08:39:39.074: E/AndroidRuntime(394):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
01-04 08:39:39.074: E/AndroidRuntime(394):  ... 11 more

这是我到目前为止的代码:

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Timer timer = new Timer();
        timer.schedule(new UpdateTimeTask(),1, 3000);


class UpdateTimeTask extends TimerTask {

            public void run() 
               {        
                // do stufff
                new status().execute();
               }

            }

那么知道如何解决这个问题吗？提前致谢

Answer 1

终于找到解决办法了:

public void callAsynchronousTask() {
    final Handler handler = new Handler();
    Timer timer = new Timer();
    TimerTask doAsynchronousTask = new TimerTask() {       
        @Override
        public void run() {
            handler.post(new Runnable() {
                public void run() {       
                    try {
                    new status().execute();
                        // PerformBackgroundTask this class is the class that extends AsynchTask 
                    } catch (Exception e) {
                        // TODO Auto-generated catch block
                    }
                }
            });
        }
    };
    timer.schedule(doAsynchronousTask, 0, 10000); //execute in every 50000 ms
}