获取当前活动的activity
打印出来的结果就是包路径加类名
代码:

 ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);        List<RunningTaskInfo> runningTasks = am.getRunningTasks(1);        RunningTaskInfo rti = runningTasks.get(0);        ComponentName component = rti.topActivity;        Log.i("tracy", component.getClassName());

记得要加个权限:
<uses-permission android:name="android.permission.GET_TASKS"></uses-permission>