判断当前的Activity的是否处于栈顶

lockAppName 是需要判断Activity的全称（包括包名）.

private boolean getTopApp(Context mContext) {

        String lockAppName = "com.celltick.lockscreen.LockerActivity";

        String topActivityName = "";

        ActivityManager am = (ActivityManager) mContext

                .getSystemService(Context.ACTIVITY_SERVICE);

        List<ActivityManager.RunningTaskInfo> runningTasks = am

                .getRunningTasks(1);

        if (runningTasks != null && !runningTasks.isEmpty()) {

            ActivityManager.RunningTaskInfo taskInfo = runningTasks.get(0);

            topActivityName = taskInfo.topActivity.getClassName();

        }

        if (lockAppName.equals(topActivityName)) {

            return true;

        }

        return false;

    }