许多应用程序都有文本,文本中是圆角矩形的web超链接,当我点击它们时,UIWebView就会打开。让我困惑的是,他们经常有自定义链接,例如,如果单词以#开头,它也是可点击的,应用程序通过打开另一个视图来响应。我该怎么做呢?是否可以用UILabel或者我需要UITextView或者其他什么?


当前回答

我们使用来自zekel的UITapGestureRecognizer类别的方便解决方案。 它使用了NSTextContainer,就像这个问题的许多答案一样。

但是,这将返回错误的字符索引。显然是因为NSTextContainer缺少关于字体样式的信息,正如这些其他帖子所指出的:

https://stackoverflow.com/a/34238382/2439941 https://stackoverflow.com/a/47358270/2439941

后改变:

NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:label.attributedText];

To:

// Apply the font of the label to the attributed text: 
NSMutableAttributedString *attributedText = [[NSMutableAttributedString alloc] initWithAttributedString:label.attributedText];
NSMutableParagraphStyle *paragraphStyle = NSMutableParagraphStyle.new;
paragraphStyle.alignment = self.label.textAlignment;
[attributedText addAttributes:@{NSFontAttributeName: label.font, NSParagraphStyleAttributeName: paragraphStyle} 
                        range:NSMakeRange(0, label.attributedText.string.length)];

// Init with attributed text from label:
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:attributedText];

结果明显更好,点击区域现在正确地从目标字符串的第一个字符开始。但最后一个字符仍然返回NO。我们期望这与我们的目标字符串具有将字体权重设置为UIFontWeightSemibold的属性有关。而上面的代码改进应用标签。整个字符串上的字体,它有一个规则的权重。

为了解决这个问题,我们进一步改进了上面的代码片段,通过遍历所有属性范围,以支持文本中的多种字体样式:

// According to https://stackoverflow.com/a/47358270/2439941 it's required to apply the paragraph style and font of the UILabel.
// However, the attributed string might contain font formatting as well, e.g. to emphasize a word in a different font style.
// Therefor copy all attributes:
NSMutableAttributedString *attributedText = [[NSMutableAttributedString alloc] initWithAttributedString:label.attributedText];
[label.attributedText enumerateAttributesInRange:NSMakeRange(0, label.attributedText.length)
                                         options:0
                                      usingBlock:^(NSDictionary<NSAttributedStringKey,id> * _Nonnull attrs, NSRange range, BOOL * _Nonnull stop) {
    // Add each attribute:
    [attributedText addAttributes:attrs
                            range:range];
    
    // In case the attributes of this range do NOT contain a font specifier, apply the font from the UILabel:
    if (![attrs objectForKey:NSFontAttributeName]) {
        [attributedText addAttributes:@{ NSFontAttributeName : label.font }
                                range:range];
    }
}];

// Init the storage with the font attributed text:
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:attributedText];

现在,该方法为半粗体字符串范围内的每个字符返回YES,这是预期的结果。

其他回答

是的,这是可能的,尽管一开始很困惑。我将进一步向您展示如何甚至可以单击文本中的任何区域。

使用这个方法,你可以有一个UI标签,如下所示:

多行友好 Autoshrink友好 可点击友好型(是的,甚至是单个角色) 斯威夫特5

步骤1:

使UILabel具有'Truncate Tail'的换行属性,并设置最小字体比例。

如果你不熟悉字体比例,请记住以下规则:

minimumFontSize/defaultFontSize = fontscale

在我的例子中,我希望7.2是最小字体大小,而我的起始字体大小是36。因此7.2 / 36 = 0.2

步骤2:

如果你不关心标签是可点击的,只是想要一个工作多行标签你就完成了!

然而,如果你想要标签是可点击阅读…

添加以下扩展我创建

extension UILabel {

    func setOptimalFontSize(maxFontSize:CGFloat,text:String){
        let width = self.bounds.size.width

        var font_size:CGFloat = maxFontSize //Set the maximum font size.
        var stringSize = NSString(string: text).size(withAttributes: [.font : self.font.withSize(font_size)])
        while(stringSize.width > width){
            font_size = font_size - 1
            stringSize = NSString(string: text).size(withAttributes: [.font : self.font.withSize(font_size)])
        }

        self.font = self.font.withSize(font_size)//Forcefully change font to match what it would be graphically.
    }
}

它的用法是这样的(只需将<Label>替换为您实际的标签名):

<Label>.setOptimalFontSize(maxFontSize: 36.0, text: formula)

这个扩展是需要的,因为自动收缩不会改变标签的'字体'属性后,它自动收缩,所以你必须通过计算它通过使用.size(withAttributes)函数模拟它的大小将与特定的字体。

这是必要的,因为检测在标签上单击的位置的解决方案需要知道确切的字体大小。

步骤3:

添加以下扩展名:

extension UITapGestureRecognizer {

    func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool {
        // Create instances of NSLayoutManager, NSTextContainer and NSTextStorage
        let layoutManager = NSLayoutManager()
        let textContainer = NSTextContainer(size: CGSize.zero)

        let mutableAttribString = NSMutableAttributedString(attributedString: label.attributedText!)
        mutableAttribString.addAttributes([NSAttributedString.Key.font: label.font!], range: NSRange(location: 0, length: label.attributedText!.length))

        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.lineSpacing = 6
        paragraphStyle.lineBreakMode = .byTruncatingTail
        paragraphStyle.alignment = .center
        mutableAttribString.addAttributes([.paragraphStyle: paragraphStyle], range: NSMakeRange(0, mutableAttribString.string.count))

        let textStorage = NSTextStorage(attributedString: mutableAttribString)

        // Configure textContainer
        textContainer.lineFragmentPadding = 0.0
        textContainer.lineBreakMode = label.lineBreakMode
        textContainer.maximumNumberOfLines = label.numberOfLines

        // Configure layoutManager and textStorage
        layoutManager.addTextContainer(textContainer)

        textStorage.addLayoutManager(layoutManager)

        let labelSize = label.bounds.size

        textContainer.size = labelSize

        // Find the tapped character location and compare it to the specified range
        let locationOfTouchInLabel = self.location(in: label)

        let textBoundingBox = layoutManager.usedRect(for: textContainer)
        //let textContainerOffset = CGPointMake((labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x,
                                              //(labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y);
        let textContainerOffset = CGPoint(x: (labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x, y: (labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y)

        //let locationOfTouchInTextContainer = CGPointMake(locationOfTouchInLabel.x - textContainerOffset.x,
                                                        // locationOfTouchInLabel.y - textContainerOffset.y);
        let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x - textContainerOffset.x, y: locationOfTouchInLabel.y - textContainerOffset.y)

        let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
        print("IndexOfCharacter=",indexOfCharacter)

        print("TargetRange=",targetRange)
        return NSLocationInRange(indexOfCharacter, targetRange)
    }

}

您将需要修改这个扩展为您的特定多行情况。在我的例子中,您将注意到我使用了段落样式。

let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.lineSpacing = 6
        paragraphStyle.lineBreakMode = .byTruncatingTail
        paragraphStyle.alignment = .center
        mutableAttribString.addAttributes([.paragraphStyle: paragraphStyle], range: NSMakeRange(0, mutableAttribString.string.count))

确保在扩展中将此更改为您实际使用的行间距,以便一切计算正确。

步骤4:

添加gestureRecognizer到标签在viewDidLoad或你认为合适的地方,就像这样(只需替换< label >与你的标签名再次:

<Label>.addGestureRecognizer(UITapGestureRecognizer(target:self, action: #selector(tapLabel(gesture:))))

这是我的tapLabel函数的一个简化示例(只需将<Label>替换为您的UILabel名称):

@IBAction func tapLabel(gesture: UITapGestureRecognizer) {
        guard let text = <Label>.attributedText?.string else {
            return
        }

        let click_range = text.range(of: "(α/β)")

        if gesture.didTapAttributedTextInLabel(label: <Label>, inRange: NSRange(click_range!, in: text)) {
           print("Tapped a/b")
        }else {
           print("Tapped none")
        }
    }

在我的例子中,我的字符串是BED = N * d * [RBE + (d / (α/β))],所以我只是在这种情况下得到α/β的范围。您可以在字符串中添加“\n”以添加换行符和任何您想要的文本,并测试此以在下一行中找到字符串,它仍然会找到它并正确地检测点击!

就是这样!你完成了。享受多行可点击标签。

以下是NAlexN的回答。

class TapabbleLabel: UILabel {

let layoutManager = NSLayoutManager()
let textContainer = NSTextContainer(size: CGSize.zero)
var textStorage = NSTextStorage() {
    didSet {
        textStorage.addLayoutManager(layoutManager)
    }
}

var onCharacterTapped: ((label: UILabel, characterIndex: Int) -> Void)?

let tapGesture = UITapGestureRecognizer()

override var attributedText: NSAttributedString? {
    didSet {
        if let attributedText = attributedText {
            textStorage = NSTextStorage(attributedString: attributedText)
        } else {
            textStorage = NSTextStorage()
        }
    }
}

override var lineBreakMode: NSLineBreakMode {
    didSet {
        textContainer.lineBreakMode = lineBreakMode
    }
}

override var numberOfLines: Int {
    didSet {
        textContainer.maximumNumberOfLines = numberOfLines
    }
}

/**
 Creates a new view with the passed coder.

 :param: aDecoder The a decoder

 :returns: the created new view.
 */
required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    setUp()
}

/**
 Creates a new view with the passed frame.

 :param: frame The frame

 :returns: the created new view.
 */
override init(frame: CGRect) {
    super.init(frame: frame)
    setUp()
}

/**
 Sets up the view.
 */
func setUp() {
    userInteractionEnabled = true
    layoutManager.addTextContainer(textContainer)
    textContainer.lineFragmentPadding = 0
    textContainer.lineBreakMode = lineBreakMode
    textContainer.maximumNumberOfLines = numberOfLines
    tapGesture.addTarget(self, action: #selector(TapabbleLabel.labelTapped(_:)))
    addGestureRecognizer(tapGesture)
}

override func layoutSubviews() {
    super.layoutSubviews()
    textContainer.size = bounds.size
}

func labelTapped(gesture: UITapGestureRecognizer) {
    guard gesture.state == .Ended else {
        return
    }

    let locationOfTouch = gesture.locationInView(gesture.view)
    let textBoundingBox = layoutManager.usedRectForTextContainer(textContainer)
    let textContainerOffset = CGPoint(x: (bounds.width - textBoundingBox.width) / 2 - textBoundingBox.minX,
                                      y: (bounds.height - textBoundingBox.height) / 2 - textBoundingBox.minY)        
    let locationOfTouchInTextContainer = CGPoint(x: locationOfTouch.x - textContainerOffset.x,
                                                 y: locationOfTouch.y - textContainerOffset.y)
    let indexOfCharacter = layoutManager.characterIndexForPoint(locationOfTouchInTextContainer,
                                                                inTextContainer: textContainer,
                                                                fractionOfDistanceBetweenInsertionPoints: nil)

    onCharacterTapped?(label: self, characterIndex: indexOfCharacter)
}
}

然后你可以在你的viewDidLoad方法中创建一个类的实例,就像这样:

let label = TapabbleLabel()
label.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(label)
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-[view]-|",
                                               options: [], metrics: nil, views: ["view" : label]))
view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-[view]-|",
                                               options: [], metrics: nil, views: ["view" : label]))

let attributedString = NSMutableAttributedString(string: "String with a link", attributes: nil)
let linkRange = NSMakeRange(14, 4); // for the word "link" in the string above

let linkAttributes: [String : AnyObject] = [
    NSForegroundColorAttributeName : UIColor.blueColor(), NSUnderlineStyleAttributeName : NSUnderlineStyle.StyleSingle.rawValue,
    NSLinkAttributeName: "http://www.apple.com"]
attributedString.setAttributes(linkAttributes, range:linkRange)

label.attributedText = attributedString

label.onCharacterTapped = { label, characterIndex in
    if let attribute = label.attributedText?.attribute(NSLinkAttributeName, atIndex: characterIndex, effectiveRange: nil) as? String,
        let url = NSURL(string: attribute) {
        UIApplication.sharedApplication().openURL(url)
    }
}

最好有一个自定义属性,以便在点击字符时使用。它是NSLinkAttributeName,但可以是任何东西你可以使用那个值去做其他的事情除了打开一个url,你可以做任何自定义动作。

(我的回答建立在@NAlexN的精彩回答之上。我不会在这里重复他对每一步的详细解释。)

我发现这是最方便和直接的添加支持可点击的UILabel文本作为类别UITapGestureRecognizer。(你不必使用UITextView的数据检测器,就像一些答案所建议的那样。)

添加以下方法到你的UITapGestureRecognizer类别:

/**
 Returns YES if the tap gesture was within the specified range of the attributed text of the label.
 */
- (BOOL)didTapAttributedTextInLabel:(UILabel *)label inRange:(NSRange)targetRange {
    NSParameterAssert(label != nil);

    CGSize labelSize = label.bounds.size;
    // create instances of NSLayoutManager, NSTextContainer and NSTextStorage
    NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];
    NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:CGSizeZero];
    NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:label.attributedText];

    // configure layoutManager and textStorage
    [layoutManager addTextContainer:textContainer];
    [textStorage addLayoutManager:layoutManager];

    // configure textContainer for the label
    textContainer.lineFragmentPadding = 0.0;
    textContainer.lineBreakMode = label.lineBreakMode;
    textContainer.maximumNumberOfLines = label.numberOfLines;
    textContainer.size = labelSize;

    // find the tapped character location and compare it to the specified range
    CGPoint locationOfTouchInLabel = [self locationInView:label];
    CGRect textBoundingBox = [layoutManager usedRectForTextContainer:textContainer];
    CGPoint textContainerOffset = CGPointMake((labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x,
                                              (labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y);
    CGPoint locationOfTouchInTextContainer = CGPointMake(locationOfTouchInLabel.x - textContainerOffset.x,
                                                         locationOfTouchInLabel.y - textContainerOffset.y);
    NSInteger indexOfCharacter = [layoutManager characterIndexForPoint:locationOfTouchInTextContainer
                                                            inTextContainer:textContainer
                                   fractionOfDistanceBetweenInsertionPoints:nil];
    if (NSLocationInRange(indexOfCharacter, targetRange)) {
        return YES;
    } else {
        return NO;
    }
}

示例代码

// (in your view controller)    
// create your label, gesture recognizer, attributed text, and get the range of the "link" in your label
myLabel.userInteractionEnabled = YES;
[myLabel addGestureRecognizer:
   [[UITapGestureRecognizer alloc] initWithTarget:self 
                                           action:@selector(handleTapOnLabel:)]]; 

// create your attributed text and keep an ivar of your "link" text range
NSAttributedString *plainText;
NSAttributedString *linkText;
plainText = [[NSMutableAttributedString alloc] initWithString:@"Add label links with UITapGestureRecognizer"
                                                   attributes:nil];
linkText = [[NSMutableAttributedString alloc] initWithString:@" Learn more..."
                                                  attributes:@{
                                                      NSForegroundColorAttributeName:[UIColor blueColor]
                                                  }];
NSMutableAttributedString *attrText = [[NSMutableAttributedString alloc] init];
[attrText appendAttributedString:plainText];
[attrText appendAttributedString:linkText];

// ivar -- keep track of the target range so you can compare in the callback
targetRange = NSMakeRange(plainText.length, linkText.length);

手势回调

// handle the gesture recognizer callback and call the category method
- (void)handleTapOnLabel:(UITapGestureRecognizer *)tapGesture {
    BOOL didTapLink = [tapGesture didTapAttributedTextInLabel:myLabel
                                            inRange:targetRange];
    NSLog(@"didTapLink: %d", didTapLink);

}

以下是基于@Luca Davanzo的回答,重写touchesBegan事件而不是轻触手势:

import UIKit

public protocol TapableLabelDelegate: NSObjectProtocol {
   func tapableLabel(_ label: TapableLabel, didTapUrl url: String, atRange range: NSRange)
}

public class TapableLabel: UILabel {

private var links: [String: NSRange] = [:]
private(set) var layoutManager = NSLayoutManager()
private(set) var textContainer = NSTextContainer(size: CGSize.zero)
private(set) var textStorage = NSTextStorage() {
    didSet {
        textStorage.addLayoutManager(layoutManager)
    }
}

public weak var delegate: TapableLabelDelegate?

public override var attributedText: NSAttributedString? {
    didSet {
        if let attributedText = attributedText {
            textStorage = NSTextStorage(attributedString: attributedText)
        } else {
            textStorage = NSTextStorage()
            links = [:]
        }
    }
}

public override var lineBreakMode: NSLineBreakMode {
    didSet {
        textContainer.lineBreakMode = lineBreakMode
    }
}

public override var numberOfLines: Int {
    didSet {
        textContainer.maximumNumberOfLines = numberOfLines
    }
}


public override init(frame: CGRect) {
    super.init(frame: frame)
    setup()
}

public required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    setup()
}

public override func layoutSubviews() {
    super.layoutSubviews()
    textContainer.size = bounds.size
}


/// addLinks
///
/// - Parameters:
///   - text: text of link
///   - url: link url string
public func addLink(_ text: String, withURL url: String) {
    guard let theText = attributedText?.string as? NSString else {
        return
    }

    let range = theText.range(of: text)

    guard range.location !=  NSNotFound else {
        return
    }

    links[url] = range
}

private func setup() {
    isUserInteractionEnabled = true
    layoutManager.addTextContainer(textContainer)
    textContainer.lineFragmentPadding = 0
    textContainer.lineBreakMode = lineBreakMode
    textContainer.maximumNumberOfLines  = numberOfLines
}

public override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    guard let locationOfTouch = touches.first?.location(in: self) else {
        return
    }

    textContainer.size = bounds.size
    let indexOfCharacter = layoutManager.glyphIndex(for: locationOfTouch, in: textContainer)

    for (urlString, range) in links {
        if NSLocationInRange(indexOfCharacter, range), let url = URL(string: urlString) {
            delegate?.tapableLabel(self, didTapUrl: urlString, atRange: range)
        }
    }
}}

这是沙玛林。基于Kedar的答案的iOS c#实现。

MyClickableTextViewWithCustomUrlScheme实现与ShouldInteractWithUrl覆盖:

// Inspired from https://stackoverflow.com/a/44112932/15186
internal class MyClickableTextViewWithCustomUrlScheme : UITextView, IUITextViewDelegate
{
    public MyClickableTextViewWithCustomUrlScheme()
    {
        Initialize();
    }

    public MyClickableTextViewWithCustomUrlScheme(Foundation.NSCoder coder) : base(coder)
    {
        Initialize();
    }

    public MyClickableTextViewWithCustomUrlScheme(Foundation.NSObjectFlag t) : base(t)
    {
        Initialize();
    }

    public MyClickableTextViewWithCustomUrlScheme(IntPtr handle) : base(handle)
    {
        Initialize();
    }

    public MyClickableTextViewWithCustomUrlScheme(CoreGraphics.CGRect frame) : base(frame)
    {
        Initialize();
    }

    public MyClickableTextViewWithCustomUrlScheme(CoreGraphics.CGRect frame, NSTextContainer textContainer) : base(frame, textContainer)
    {
        Initialize();
    }

    void Initialize()
    {
        Delegate = this;
    }

    [Export("textView:shouldInteractWithURL:inRange:")]
    public new bool ShouldInteractWithUrl(UITextView textView, NSUrl URL, NSRange characterRange)
    {
        if (URL.Scheme.CompareTo(@"username") == 0)
        {
            // Launch the Activity
            return false;
        }
        // The system will handle the URL
        return base.ShouldInteractWithUrl(textView, URL, characterRange);
    }
}

在c#中转换的objective-C代码变成:

MyClickableTextViewWithCustomUrlScheme uiHabitTile = new MyClickableTextViewWithCustomUrlScheme();
uiHabitTile.Selectable = true;
uiHabitTile.ScrollEnabled = false;
uiHabitTile.Editable = false;

// https://stackoverflow.com/a/34014655/15186
string wholeTitle = @"This is an example by marcelofabri";

NSMutableAttributedString attributedString = new NSMutableAttributedString(wholeTitle);
attributedString.AddAttribute(UIStringAttributeKey.Link,
   new NSString("username://marcelofabri"),
   attributedString.Value.RangeOfString(@"marcelofabri")
);
NSMutableDictionary<NSString, NSObject> linkAttributes = new NSMutableDictionary<NSString, NSObject>();
linkAttributes[UIStringAttributeKey.ForegroundColor] = UIColor.Green;
linkAttributes[UIStringAttributeKey.UnderlineColor] = UIColor.LightGray;
linkAttributes[UIStringAttributeKey.UnderlineStyle] = new NSNumber((short)NSUnderlineStyle.PatternSolid);

uiHabitTile.AttributedText = attributedString;

确保将Editable = false和Selectable = true设置为能够单击链接。

同样,ScrollEnabled = true允许textview正确地调整其高度大小。