所以我尝试解析一个字符串并用转换为字符串的每个字符填充一个数组，我还删除了空格。部分代码如下:classKeyboardView:UIView{varanswer:AnyObject?varkeyboardLetters=[String]()overridefuncwillMoveToSuperview(newSuperview:UIView?){forletterinanswer!asString{ifletter!=""{keyboardLetters.append(String(letter).lowercaseString)}}}}当我删除for循环时，错误消失，并且只发生在i