使用例如以下方法能够获得top activity 的name

public String getTopActivityPackageName(Context context) {

    String topActivityPackage = null;

    ActivityManager activityManager = (ActivityManager) (context

            .getSystemService(android.content.Context.ACTIVITY_SERVICE));

    List<RunningTaskInfo> runningTaskInfos = activityManager

            .getRunningTasks(1);

    if (runningTaskInfos != null) {

        ComponentName f = runningTaskInfos.get(0).topActivity;

        topActivityPackage = f.getPackageName();

    }

    return topActivityPackage;

}