Android 判断Activity是否在最顶层

在Android开发的过程中，有时候要判断某个Activity时候再最上层，这里有个方法，大家可以参考

public static boolean isTopActivity(Activity activity) {
    ActivityManager am = (ActivityManager)activity.getSystemService(ACTIVITY_SERVICE);
    ComponentName cn = am.getRunningTasks(1).get(0).topActivity;
    return cn.getClassName().contains(activity.getLocalClassName());
}