UIButton上的iOS NSAttributedString

Question

我使用的是iOS 6,所以归因字符串应该很容易使用,对吧？嗯......不是那么多.

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,属性标题,即:

1. 第一行上的所有大写(我意识到这不是属性的一部分)
2. 在第一行加粗
3. 在第一行加下划线
4. 第二行"正常"重量
5. 第二行没有下划线
6. 以两条线为中心

到目前为止,我已经能够获得#1到5(至少,我认为我做过,但是当前的测试会产生多行文本错误),但是当我尝试做某事(任何东西!)时要居中的文本,我的应用程序不断崩溃.当我尝试使所有6个项目工作(通过各种方法)时,我得到以下崩溃/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,似乎我可以有以下选项之一,但不是两个:

1. 多线,居中的标签
2. 属性标签

如果必须的话,我可以与其中一个生活在一起,但我无法相信我不能拥有一个看起来相当简单的概念.

谁能告诉我我错了什么？

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];

Answer 1

在我看来,你忘了在你的代码中使用你设置的"样式"对象..你只是实例化它.您应该修改您的代码,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..其他一切都是相同的...这就是我得到的按钮:

这是在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

Answer 2

两行标题UIButton为：NSAttributedStringSwift 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)
}

Answer 3

使用Swift 4,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])
    }

}

如果您确实需要类型的按钮system,则可以使用以下代码:

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: