获取当前活动的activity与实例的方法

如果要获取实例，可通过使用一个局部public且static变量，在每生成一个Activity时，进行赋值，经试验，可行

http://wangzhigang2.iteye.com/blog/1276923

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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>