请问如何实现多个activity下按Home键实现对应通知栏状态Notification

Question

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {           if (keyCode == KeyEvent.KEYCODE_HOME) {
            NotificationManager nm = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
            Notification n = new Notification();
            n.icon = R.drawable.golf_ball;
            n.when = System.currentTimeMillis();
            n.flags = Notification.FLAG_AUTO_CANCEL;
            Context context = getApplicationContext();
            Intent intent = new Intent(context,getLocalActivityManager().getCurrentActivity().getClass());
            PendingIntent pi = PendingIntent.getActivity(context,0,intent,0);
            n.setLatestEventInfo(context, "GolfSystem", "GolfSystem正在后台运行", pi);
            nm.notify(1, n);
            
Intent it = new Intent(Intent.ACTION_MAIN);
it.addCategory(Intent.CATEGORY_HOME);
it.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(it);           }
           return super.onKeyDown(keyCode, event);    };

Answer 1

Intent intent = new Intent(context,getLocalActivityManager().getCurrentActivity().getClass());
走到这一步一直报空指针错，getLocalActivityManager().getCurrentActivity()这个的值是空，不知道为什么

Answer 2

Intent intent = new Intent(context,getLocalActivityManager().getCurrentActivity().getClass());
intent改一下试试：
ActivityManager manager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
ComponentName cn = manager.getRunningTasks(1).get(0).topActivity
intent.setComponent(cn)

Answer 3

改成你那样的之后报了这个错，
06-01 11:48:53.404: E/AndroidRuntime(352): FATAL EXCEPTION: main
06-01 11:48:53.404: E/AndroidRuntime(352): java.lang.SecurityException: Permission Denial: getTasks() from pid=352, uid=10048 requires android.permission.GET_TASKS
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.os.Parcel.readException(Parcel.java:1247)
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.os.Parcel.readException(Parcel.java:1235)
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.app.ActivityManagerProxy.getTasks(ActivityManagerNative.java:1645)
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.app.ActivityManager.getRunningTasks(ActivityManager.java:298)
06-01 11:48:53.404: E/AndroidRuntime(352):  at com.cn.ui.BaseActivity.onKeyDown(BaseActivity.java:900)
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.view.KeyEvent.dispatch(KeyEvent.java:1037)
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.app.Activity.dispatchKeyEvent(Activity.java:2068)
06-01 11:48:53.404: E/AndroidRuntime(352):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1643)
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.view.ViewRoot.deliverKeyEventToViewHierarchy(ViewRoot.java:2471)
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.view.ViewRoot.handleFinishedEvent(ViewRoot.java:2441)
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.view.ViewRoot.handleMessage(ViewRoot.java:1735)
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.os.Handler.dispatchMessage(Handler.java:99)
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.os.Looper.loop(Looper.java:123)
06-01 11:48:53.404: E/AndroidRuntime(352):  at android.app.ActivityThread.main(ActivityThread.java:4627)
06-01 11:48:53.404: E/AndroidRuntime(352):  at java.lang.reflect.Method.invokeNative(Native Method)
06-01 11:48:53.404: E/AndroidRuntime(352):  at java.lang.reflect.Method.invoke(Method.java:521)
06-01 11:48:53.404: E/AndroidRuntime(352):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
06-01 11:48:53.404: E/AndroidRuntime(352):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
06-01 11:48:53.404: E/AndroidRuntime(352):  at dalvik.system.NativeStart.main(Native Method)

Answer 4

<uses-permission android:name="android.permission.GET_TASKS"/>