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我有服务，它使用 AsyncTask 连接到服务器。解析响应后，我需要发出通知和振动，但得到 NullpointerException。

@Override
protected void onPostExecute(String[] result) {
ReconnectCallback(result);
super.onPostExecute(result);
}

public void ReconnectCallback(String[] params) {
    Handler mHandler = new Handler();


    Notification notif = new Notification(R.drawable.ic_launcher, "Connection error", System.currentTimeMillis());


    Intent x = new Intent();
    PendingIntent pIntent = PendingIntent.getActivity(MyApplication.getAppContext() , 0, new Intent(), 0);

    notif.flags |= Notification.FLAG_AUTO_CANCEL;
    v.vibrate(new long[] { 300, 300 }, -1);
    notif.setLatestEventInfo(MyApplication.getAppContext(), "Taxi driver error!", "Err: parse exception", pIntent);
    nm.notify(9999, notif);

日志

11-05 12:22:12.829: E/AndroidRuntime(13698): FATAL EXCEPTION: main
11-05 12:22:12.829: E/AndroidRuntime(13698): java.lang.NullPointerException
11-05 12:22:12.829: E/AndroidRuntime(13698):    at com.pkg.ReconnectCallback(NetworkService.java:240)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at com.pkg.NetworkService$startReconnection.onPostExecute(NetworkService.java:185)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at com.pkg.NetworkService$startReconnection.onPostExecute(NetworkService.java:1)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at android.os.AsyncTask.finish(AsyncTask.java:417)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at android.os.AsyncTask.access$300(AsyncTask.java:127)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at android.os.Handler.dispatchMessage(Handler.java:99)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at android.os.Looper.loop(Looper.java:130)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at android.app.ActivityThread.main(ActivityThread.java:3835)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at java.lang.reflect.Method.invokeNative(Native Method)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at java.lang.reflect.Method.invoke(Method.java:507)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
11-05 12:22:12.829: E/AndroidRuntime(13698):    at dalvik.system.NativeStart.main(Native Method)

    v.vibrate(new long[] { 300, 300 }, -1);
    nm.notify(9999, notif);

导致 NPE。怎么了？

@Override
public void onCreate() {
    // TODO Auto-generated method stub
    nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    v = (Vibrator) getSystemService(VIBRATOR_SERVICE);
    super.onCreate();
}
4

1 回答 1

1

v和/或显然nm是null。当然，null如果要相信您的堆栈跟踪，则这两者之一是。

于 2012-11-05T11:43:15.427 回答