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

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。

其他回答

我遵循这个版本,

斯威夫特4:

import Foundation

class AELinkedClickableUILabel: UILabel {

    typealias YourCompletion = () -> Void

    var linkedRange: NSRange!
    var completion: YourCompletion?

    @objc func linkClicked(sender: UITapGestureRecognizer){

        if let completionBlock = completion {

            let textView = UITextView(frame: self.frame)
            textView.text = self.text
            textView.attributedText = self.attributedText
            let index = textView.layoutManager.characterIndex(for: sender.location(in: self),
                                                              in: textView.textContainer,
                                                              fractionOfDistanceBetweenInsertionPoints: nil)

            if linkedRange.lowerBound <= index && linkedRange.upperBound >= index {

                completionBlock()
            }
        }
    }

/**
 *  This method will be used to set an attributed text specifying the linked text with a
 *  handler when the link is clicked
 */
    public func setLinkedTextWithHandler(text:String, link: String, handler: @escaping ()->()) -> Bool {

        let attributextText = NSMutableAttributedString(string: text)
        let foundRange = attributextText.mutableString.range(of: link)

        if foundRange.location != NSNotFound {
            self.linkedRange = foundRange
            self.completion = handler
            attributextText.addAttribute(NSAttributedStringKey.link, value: text, range: foundRange)
            self.isUserInteractionEnabled = true
            self.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(linkClicked(sender:))))
            return true
        }
        return false
    }
}

电话的例子:

button.setLinkedTextWithHandler(text: "This website (stackoverflow.com) is awesome", link: "stackoverflow.com") 
{
    // show popup or open to link
}

我强烈建议使用自动检测文本中的url并将其转换为链接的库。 试一试:

TTTAttributedLabel (pod) ZSWTappableLabel (under).

两者都得到了麻省理工学院的许可。

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)
        }
    }
}}

一般来说,如果我们想在UILabel显示的文本中有一个可点击的链接,我们需要解决两个独立的任务:

更改部分文本的外观,使其看起来像链接 检测和处理链接上的触摸(打开URL是一个特殊情况)

第一个很简单。从ios6开始,UILabel支持显示带属性的字符串。你所需要做的就是创建并配置一个NSMutableAttributedString实例:

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:@"String with a link" attributes:nil];
NSRange linkRange = NSMakeRange(14, 4); // for the word "link" in the string above

NSDictionary *linkAttributes = @{ NSForegroundColorAttributeName : [UIColor colorWithRed:0.05 green:0.4 blue:0.65 alpha:1.0],
                                  NSUnderlineStyleAttributeName : @(NSUnderlineStyleSingle) };
[attributedString setAttributes:linkAttributes range:linkRange];

// Assign attributedText to UILabel
label.attributedText = attributedString;

就是这样!上面的代码使UILabel显示带有链接的String

现在我们应该检测这个链接上的触摸。其思想是捕获UILabel中的所有点击,并确定点击的位置是否足够接近链接。为了捕捉触摸,我们可以在标签中添加点击手势识别器。确保为标签启用userInteraction,默认情况下是关闭的:

label.userInteractionEnabled = YES;
[label addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapOnLabel:)]]; 

现在最复杂的事情是:找出点击是否在显示链接的地方,而不是在标签的任何其他部分。如果我们有单行UILabel,这个任务可以通过硬编码链接显示的区域边界来相对容易地解决,但是让我们更优雅地解决这个问题,对于一般情况-多行UILabel,而不需要对链接布局有初步的了解。

其中一种方法是使用iOS 7中引入的Text Kit API功能:

// Create instances of NSLayoutManager, NSTextContainer and NSTextStorage
NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];
NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:CGSizeZero];
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:attributedString];

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

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

将创建和配置的NSLayoutManager, NSTextContainer和NSTextStorage实例保存在类的属性中(很可能是UIViewController的后代)-我们将在其他方法中需要它们。

现在,每当标签改变它的框架,更新textContainer的大小:

- (void)viewDidLayoutSubviews
{
    [super viewDidLayoutSubviews];
    self.textContainer.size = self.label.bounds.size;
}

最后,检测点击是否恰好在链接上:

- (void)handleTapOnLabel:(UITapGestureRecognizer *)tapGesture
{
    CGPoint locationOfTouchInLabel = [tapGesture locationInView:tapGesture.view];
    CGSize labelSize = tapGesture.view.bounds.size;
    CGRect textBoundingBox = [self.layoutManager usedRectForTextContainer:self.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 = [self.layoutManager characterIndexForPoint:locationOfTouchInTextContainer
                                                            inTextContainer:self.textContainer
                                   fractionOfDistanceBetweenInsertionPoints:nil];
    NSRange linkRange = NSMakeRange(14, 4); // it's better to save the range somewhere when it was originally used for marking link in attributed string
    if (NSLocationInRange(indexOfCharacter, linkRange)) {
        // Open an URL, or handle the tap on the link in any other way
        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"https://stackoverflow.com/"]];
    }
}

基于Charles Gamble的答案,这是我使用的(我删除了一些让我困惑并给我错误索引的行):

- (BOOL)didTapAttributedTextInLabel:(UILabel *)label inRange:(NSRange)targetRange TapGesture:(UIGestureRecognizer*) gesture{
    NSParameterAssert(label != nil);

    // create instances of NSLayoutManager, NSTextContainer and NSTextStorage
    NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];
    NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:label.attributedText];

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

    // configure textContainer for the label
    NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:CGSizeMake(label.frame.size.width, label.frame.size.height)];

    textContainer.lineFragmentPadding = 0.0;
    textContainer.lineBreakMode = label.lineBreakMode;
    textContainer.maximumNumberOfLines = label.numberOfLines;

    // find the tapped character location and compare it to the specified range
    CGPoint locationOfTouchInLabel = [gesture locationInView:label];
    [layoutManager addTextContainer:textContainer]; //(move here, not sure it that matter that calling this line after textContainer is set

    NSInteger indexOfCharacter = [layoutManager characterIndexForPoint:locationOfTouchInLabel
                                                           inTextContainer:textContainer
                                  fractionOfDistanceBetweenInsertionPoints:nil];
    if (NSLocationInRange(indexOfCharacter, targetRange)) {
        return YES;
    } else {
        return NO;
    }
}