ios - 扩展可能不包含 UItextfield 中的存储属性

Question

extension UITextField
@IBInspectable var placeholdercolor: UIColor 
    {
    willSet {
         attributedPlaceholder = NSAttributedString(string: placeholder != nil ?  placeholder! : "", attributes:[NSAttributedStringKey.foregroundColor: placeholdercolor])
    }}

我正在为占位符颜色的 UITextField 创建扩展。我不想创建自定义类，我也尝试

@IBInspectable var placeholdercolor: UIColor 
    {
get
    {
       return self.placeholdercolor 
    }
    set
    {
        attributedPlaceholder = NSAttributedString(string: placeholder != nil ?  placeholder! : "", attributes:[NSAttributedStringKey.foregroundColor: placeholdercolor])
    }
}

但它在方法上给出错误(线程 1:EXC_BAD_ACCESS)

get
    {
       return self.placeholdercolor 
    }

请帮忙

Answer 1

@IBInspectable var placeholdercolor: UIColor 
    {
get
    { // you can't return this here because this will call the getter again and again -> Stack Overflow
       return self.placeholdercolor 
    }
    set
    {
        attributedPlaceholder = NSAttributedString(string: placeholder != nil ?  placeholder! : "", attributes:[NSAttributedStringKey.foregroundColor: placeholdercolor])
    }
}

你应该在 getter 中返回属性字符串中的前景色属性:

get
    {
       return attributedPlaceholder?.attribute(NSForegroundColorAttributeName, at: 0, effectiveRange: nil) as? UIColor
    }

我建议您将此属性设置为可选属性，以防未设置该属性。

编辑:

您的二传手也不正确。您应该使用 newValue:

attributedPlaceholder = NSAttributedString(string: placeholder != nil ?  placeholder! : "", attributes:[NSAttributedStringKey.foregroundColor: newValue])