ios - UIButton 上的 iOS NSAttributedString

Question

我使用的是iOS 6，所以属性字符串应该很容易使用，对吧？嗯……没那么多。

我想做的事：

使用自定义子类UIButton（它不做任何自定义titleLabel），我想要一个多行的属性标题，即：

第一行全部大写（我意识到这不是属性的一部分）
在第一行加粗
第一行有下划线
第二行的“正常”重量
第二行无下划线
以两条线为中心

到目前为止，我已经能够得到 # 的 1 到 5（至少，我认为我做到了，但是当前的测试产生了多行文本的错误），但是当我尝试做某事（任何事情！）时要居中的文本，我的应用程序不断崩溃。当我尝试让所有 6 项工作（通过各种方法）时，我收到以下崩溃/错误：

Terminating app due to uncaught exception 
'NSInternalInconsistencyException', reason: 
'NSAttributedString invalid for autoresizing, 
it must have a single spanning paragraph style
(or none) with a non-wrapping lineBreakMode.'

根据我的尝试，我似乎可以有以下选项之一，但不能同时拥有：

多行居中标签
属性标签

如果必须的话，我可以接受其中一个，但我不敢相信我不能拥有一个看似相当简单的概念。

有人可以告诉我我做错了什么吗？

这是我正在尝试的代码的最后一次迭代：

NSMutableParagraphStyle *style = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
[style setAlignment:NSTextAlignmentCenter];
[style setLineBreakMode:NSLineBreakByWordWrapping];

UIFont *font1 = [UIFont fontWithName:@"HelveticaNeue-Medium" size:20.0f];
UIFont *font2 = [UIFont fontWithName:@"HelveticaNeue-Light"  size:20.0f];
NSDictionary *dict1 = @{NSUnderlineStyleAttributeName:@(NSUnderlineStyleSingle),  
                        NSFontAttributeName:font1};
NSDictionary *dict2 = @{NSUnderlineStyleAttributeName:@(NSUnderlineStyleNone),    
                        NSFontAttributeName:font2};

NSMutableAttributedString *attString = [[NSMutableAttributedString alloc] init];
[attString appendAttributedString:[[NSAttributedString alloc] initWithString:@"LINE 1\n"    attributes:dict1]];
[attString appendAttributedString:[[NSAttributedString alloc] initWithString:@"line 2"      attributes:dict2]];
[[self buttonToStyle] setAttributedTitle:attString forState:UIControlStateNormal];
[[[self buttonToStyle] titleLabel] setNumberOfLines:0];
[[[self buttonToStyle] titleLabel] setLineBreakMode:NSLineBreakByWordWrapping];

score 103 · Accepted Answer

在我看来，您好像忘记了在代码中使用您设置的“样式”对象......您只是实例化了它。您应该将代码修改为如下所示：

NSMutableParagraphStyle *style = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
[style setAlignment:NSTextAlignmentCenter];
[style setLineBreakMode:NSLineBreakByWordWrapping];

UIFont *font1 = [UIFont fontWithName:@"HelveticaNeue-Medium" size:20.0f];
UIFont *font2 = [UIFont fontWithName:@"HelveticaNeue-Light"  size:20.0f];
NSDictionary *dict1 = @{NSUnderlineStyleAttributeName:@(NSUnderlineStyleSingle),
                        NSFontAttributeName:font1,
                        NSParagraphStyleAttributeName:style}; // Added line
NSDictionary *dict2 = @{NSUnderlineStyleAttributeName:@(NSUnderlineStyleNone),
                        NSFontAttributeName:font2,
                        NSParagraphStyleAttributeName:style}; // Added line

NSMutableAttributedString *attString = [[NSMutableAttributedString alloc] init];
[attString appendAttributedString:[[NSAttributedString alloc] initWithString:@"LINE 1\n"    attributes:dict1]];
[attString appendAttributedString:[[NSAttributedString alloc] initWithString:@"line 2"      attributes:dict2]];
[self.resolveButton setAttributedTitle:attString forState:UIControlStateNormal];
[[self.resolveButton titleLabel] setNumberOfLines:0];
[[self.resolveButton titleLabel] setLineBreakMode:NSLineBreakByWordWrapping];

请注意，我只添加了定义 NSParagraphStyleAttributeName 的行。其他一切都是一样的。这就是我为按钮得到的：

在此处输入图像描述

它在 Swift 3.0 中

let style = NSMutableParagraphStyle()
style.alignment = .center
style.lineBreakMode = .byWordWrapping

guard
    let font1 = UIFont(name: "HelveticaNeue-Medium", size: 20),
    let font2 = UIFont(name: "HelveticaNeue-Light", size: 20)  else { return }

let dict1:[String:Any] = [
    NSUnderlineStyleAttributeName:NSUnderlineStyle.styleSingle.rawValue,
    NSFontAttributeName:font1,
    NSParagraphStyleAttributeName:style
]

let dict2:[String:Any] = [
    NSUnderlineStyleAttributeName:NSUnderlineStyle.styleNone.rawValue,
    NSFontAttributeName:font2,
    NSParagraphStyleAttributeName:style
]

let attString = NSMutableAttributedString()
attString.append(NSAttributedString(string: "LINE 1", attributes: dict1))
attString.append(NSAttributedString(string: "line 2", attributes: dict2))

button.setAttributedTitle(attString, for: .normal)
button.titleLabel?.numberOfLines = 0
button.titleLabel?.lineBreakMode = .byWordWrapping

score 15 · Accepted Answer

使用 Swift 5.1 和 iOS 13.1，您可以使用UIButton下面的子类实现来解决您的问题：

import UIKit

class CustomButton: UIButton {

    required init(title: String, subtitle: String) {
        super.init(frame: CGRect.zero)

        let style = NSMutableParagraphStyle()
        style.alignment = NSTextAlignment.center
        style.lineBreakMode = NSLineBreakMode.byWordWrapping

        let titleAttributes: [NSAttributedString.Key : Any] = [
            NSAttributedString.Key.foregroundColor: UIColor.label,
            NSAttributedString.Key.underlineStyle : NSUnderlineStyle.single.rawValue,
            NSAttributedString.Key.font : UIFont.preferredFont(forTextStyle: UIFont.TextStyle.largeTitle),
            NSAttributedString.Key.paragraphStyle : style
        ]
        let subtitleAttributes = [
            NSAttributedString.Key.foregroundColor: UIColor.label,
            NSAttributedString.Key.font : UIFont.preferredFont(forTextStyle: UIFont.TextStyle.body),
            NSAttributedString.Key.paragraphStyle : style
        ]

        let attributedString = NSMutableAttributedString(string: title, attributes: titleAttributes)
        attributedString.append(NSAttributedString(string: "\n"))
        attributedString.append(NSAttributedString(string: subtitle, attributes: subtitleAttributes))

        setAttributedTitle(attributedString, for: UIControl.State.normal)
        titleLabel?.numberOfLines = 0
        titleLabel?.lineBreakMode = NSLineBreakMode.byWordWrapping
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}

用法：

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let button = CustomButton(title: "Title", subtitle: "Subtitle")
        button.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(button)

        let horizontalConstraint = button.centerXAnchor.constraint(equalTo: view.centerXAnchor)
        let verticalConstraint = button.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        NSLayoutConstraint.activate([horizontalConstraint, verticalConstraint])
    }

}

作为替代方案，如果您确实需要一个类型的按钮system，您可以使用以下代码：

import UIKit

extension UIButton {

    static func customSystemButton(title: String, subtitle: String) -> UIButton {
        let style = NSMutableParagraphStyle()
        style.alignment = NSTextAlignment.center
        style.lineBreakMode = NSLineBreakMode.byWordWrapping

        let titleAttributes: [NSAttributedString.Key : Any] = [
            NSAttributedString.Key.underlineStyle : NSUnderlineStyle.single.rawValue,
            NSAttributedString.Key.font : UIFont.preferredFont(forTextStyle: UIFont.TextStyle.largeTitle),
            NSAttributedString.Key.paragraphStyle : style
        ]
        let subtitleAttributes = [
            NSAttributedString.Key.font : UIFont.preferredFont(forTextStyle: UIFont.TextStyle.body),
            NSAttributedString.Key.paragraphStyle : style
        ]

        let attributedString = NSMutableAttributedString(string: title, attributes: titleAttributes)
        attributedString.append(NSAttributedString(string: "\n"))
        attributedString.append(NSAttributedString(string: subtitle, attributes: subtitleAttributes))

        let button = UIButton(type: UIButton.ButtonType.system)
        button.setAttributedTitle(attributedString, for: UIControl.State.normal)
        button.titleLabel?.numberOfLines = 0
        button.titleLabel?.lineBreakMode = NSLineBreakMode.byWordWrapping

        return button
    }

}

用法：

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let button = UIButton.customSystemButton(title: "Title", subtitle: "Subtitle")
        button.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(button)

        let horizontalConstraint = button.centerXAnchor.constraint(equalTo: view.centerXAnchor)
        let verticalConstraint = button.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        NSLayoutConstraint.activate([horizontalConstraint, verticalConstraint])
    }

}

下面的两个屏幕截图显示了UIButton子类（左侧）和system类型按钮（右侧）的结果显示：

score 8 · Accepted Answer

UIButton带有NSAttributedString标题的两行Swift 5.1：

func customizeSubscribeButton() {
    subscribeButton.titleLabel?.numberOfLines = 2
    let title = NSMutableAttributedString()
    let paragraphStyle = NSMutableParagraphStyle()
    paragraphStyle.alignment = .center
    let part1 = NSAttributedString(string: "SUBSCRIBE FOR 12 MONTH\n",
                                   attributes: [NSAttributedString.Key.foregroundColor: UIColor.white,
                                                NSAttributedString.Key.font: UIFont.systemFont(ofSize: 24, weight: .semibold),
                                                NSAttributedString.Key.paragraphStyle: paragraphStyle])
    let part2 = NSAttributedString(string: "999.00 RUB ECONOMY 85%",
                                   attributes: [NSAttributedString.Key.foregroundColor: UIColor.white,
                                                NSAttributedString.Key.font: UIFont.systemFont(ofSize: 12, weight: .light),
                                                NSAttributedString.Key.paragraphStyle: paragraphStyle])
    title.append(part1)
    title.append(part2)
    subscribeButton.setAttributedTitle(title, for: .normal)
}

ios - UIButton 上的 iOS NSAttributedString

3 回答 3

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