Question

我正在iOS上制作自定义渲染器，以获取UILabel的Underline和StrikeThrough。使用

var stringAttributes = new NSMutableAttributedString(Control.Text,new UIStringAttributes{ UnderlineStyle = NSUnderlineStyle.Thick, UnderlineColor = UIColor.Black, BackgroundColor = UIColor.Brown});

工作完美。

但使用AddAttribute不会更新UiLabel

{
    var stringAttributes = new NSMutableAttributedString(Control.AttributedText);
    if (OutField.FontAttr.CrossedOut)
    {
        stringAttributes.AddAttribute(new NSString("UnderlineStyle"),
                                      NSNumber.FromInt32((int)NSUnderlineStyle.Thick),
            new NSRange(0, Element.Text.Length));
        stringAttributes.AddAttribute(new NSString("UnderlineColor"),
                                      Control.TextColor,
                                      new NSRange(0, Element.Text.Length));
    }
    if (OutField.FontAttr.Underlined)
    {
        stringAttributes.AddAttribute(new NSString("UnderlineStyle"),
            NSNumber.FromInt32((int)NSUnderlineStyle.Single),
                                      new NSRange(0, Element.Text.Length));
        stringAttributes.AddAttribute(new NSString("UnderlineColor"),
                                      Control.TextColor,
    new NSRange(0, Element.Text.Length));
    }
    Control.AttributedText = stringAttributes;
}

我在没有运气的情况下试图做不同的事情每次更改选项时，仅使用新的NSMutableAttributedString对象

NSMutableAttributedString stringAttributes = null;
if (OutField.FontAttr.CrossedOut && OutField.FontAttr.Underlined)
{
    stringAttributes = new NSMutableAttributedString(Control.Text, new UIStringAttributes
    {
        UnderlineStyle = NSUnderlineStyle.Single,
        UnderlineColor = Control.TextColor,
        StrikethroughStyle = NSUnderlineStyle.Single,
        StrikethroughColor = Control.TextColor
    });
}
else if (OutField.FontAttr.Underlined)
{
    stringAttributes = new NSMutableAttributedString(Control.Text, new UIStringAttributes
    {
        UnderlineStyle = NSUnderlineStyle.Single,
        UnderlineColor = Control.TextColor,
        StrikethroughStyle = NSUnderlineStyle.Single,
        StrikethroughColor = Control.TextColor
    });
}
else if (OutField.FontAttr.CrossedOut)
{
    stringAttributes = new NSMutableAttributedString(Control.Text, new UIStringAttributes
    {
        UnderlineStyle = NSUnderlineStyle.Single,
        UnderlineColor = Control.TextColor,
        StrikethroughStyle = NSUnderlineStyle.Single,
        StrikethroughColor = Control.TextColor
    });
}
if (stringAttributes != null)
{
    Control.AttributedText = stringAttributes;
}

Answer 1

答案实际上是一种解决方法

Xamarin.ios NSUnderlineStyle.Single中的

不起作用，我改用NSUnderlineStyle.Think。

stringAttributes.AddAttribute()无法正常工作，所以我坚持使用Control.AttributedText = stringAttributes.

我明白了，但是如果我使用多行文本删除线不起作用，显然，这是iOS中的一个已知问题：https://github.com/lionheart/openradar-mirror/issues/17165 这是xamarin的解决方法 http://www.openradar.me/31174934

使用AddAttribute的下划线和删除线无法正确更新

1 个答案: