Objective-C中如何创建带虚线下划线的UIButton

Question

普通下划线可以使用，但点状下划线似乎不起作用？

UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom]; 
btn.frame = CGRectMake(100, 10, 300, 300);
NSMutableAttributedString *titleString = [[NSMutableAttributedString alloc] initWithString:@"Durga Vundavalli"];

// making text property to underline text-
[titleString addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleSingle] range:NSMakeRange(0, [titleString length])];

// using text on button
[btn setAttributedTitle: titleString forState:UIControlStateNormal];
[self.view addSubview:btn];

以下是文档中提到的枚举类型：

typedef NS_ENUM(NSInteger, NSUnderlineStyle) {
    NSUnderlineStyleNone                                = 0x00,
    NSUnderlineStyleSingle                              = 0x01,
    NSUnderlineStyleThick NS_ENUM_AVAILABLE_IOS(7_0)    = 0x02,
    NSUnderlineStyleDouble NS_ENUM_AVAILABLE_IOS(7_0)   = 0x09,

    NSUnderlinePatternSolid NS_ENUM_AVAILABLE_IOS(7_0)      = 0x0000,
    NSUnderlinePatternDot NS_ENUM_AVAILABLE_IOS(7_0)        = 0x0100,
    NSUnderlinePatternDash NS_ENUM_AVAILABLE_IOS(7_0)       = 0x0200,
    NSUnderlinePatternDashDot NS_ENUM_AVAILABLE_IOS(7_0)    = 0x0300,
    NSUnderlinePatternDashDotDot NS_ENUM_AVAILABLE_IOS(7_0) = 0x0400,

    NSUnderlineByWord NS_ENUM_AVAILABLE_IOS(7_0) = 0x8000
}

- Durga Vundavalli

Answer 1

如果你想要两行点，就不能只使用NSUnderlinePatternDot。你需要使用一个Pattern和一个Style。

[titleString addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:(NSUnderlinePatternDot|NSUnderlineStyleSingle)] range:NSMakeRange(0, [titleString length])];

根据医生的建议，你必须戴口罩：

讨论
样式、图案和可选的逐字遮罩被OR'd在一起以产生NSUnderlineStyleAttributeName和NSStrikethroughStyleAttributeName的值。

- Larme