如何获得在后台获得当前正在展示的activity?

首先加个权限: 

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

 

ActivityManager manager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);  
List<RunningTaskInfo> runningTasks = manager .getRunningTasks(1);  
RunningTaskInfo cinfo = runningTasks.get(0);  
ComponentName component = cinfo.topActivity;  
Log.e("currentactivity", component.getClassName());
得到的是当前activity的包加类名