获取控件的key

unsigned int count = 0;

    Ivar *ivarList = class_copyIvarList([UIAlertAction class], &count);

    for (int i = 0; i<count; i++) {

        Ivar ivar = ivarList[i];

        printf(" 看看：%s\n",ivar_getName(ivar));

    }

    free(ivarList);