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

这是一个Objective-C类别,它支持现有UILabel中的可点击链接。attributedText字符串,利用现有的NSLinkAttributeName属性。

@interface UILabel (GSBClickableLinks) <UIGestureRecognizerDelegate>
@property BOOL enableLinks;
@end

#import <objc/runtime.h>
static const void *INDEX;
static const void *TAP;

@implementation UILabel (GSBClickableLinks)

- (void)setEnableLinks:(BOOL)enableLinks
{
    UITapGestureRecognizer *tap = objc_getAssociatedObject(self, &TAP); // retreive tap
    if (enableLinks && !tap) { // add a gestureRegonzier to the UILabel to detect taps
        tap = [UITapGestureRecognizer.alloc initWithTarget:self action:@selector(openLink)];
        tap.delegate = self;
        [self addGestureRecognizer:tap];
        objc_setAssociatedObject(self, &TAP, tap, OBJC_ASSOCIATION_RETAIN_NONATOMIC); // save tap
    }
    self.userInteractionEnabled = enableLinks; // note - when false UILAbel wont receive taps, hence disable links
}

- (BOOL)enableLinks
{
    return (BOOL)objc_getAssociatedObject(self, &TAP); // ie tap != nil
}

// First check whether user tapped on a link within the attributedText of the label.
// If so, then the our label's gestureRecogizer will subsequently fire, and open the corresponding NSLinkAttributeName.
// If not, then the tap will get passed along, eg to the enclosing UITableViewCell...
// Note: save which character in the attributedText was clicked so that we dont have to redo everything again in openLink.
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
    if (gestureRecognizer != objc_getAssociatedObject(self, &TAP)) return YES; // dont block other gestures (eg swipe)

    // Re-layout the attributedText to find out what was tapped
    NSTextContainer *textContainer = [NSTextContainer.alloc initWithSize:self.frame.size];
    textContainer.lineFragmentPadding = 0;
    textContainer.maximumNumberOfLines = self.numberOfLines;
    textContainer.lineBreakMode = self.lineBreakMode;
    NSLayoutManager *layoutManager = NSLayoutManager.new;
    [layoutManager addTextContainer:textContainer];
    NSTextStorage *textStorage = [NSTextStorage.alloc initWithAttributedString:self.attributedText];
    [textStorage addLayoutManager:layoutManager];

    NSUInteger index = [layoutManager characterIndexForPoint:[gestureRecognizer locationInView:self]
                                             inTextContainer:textContainer
                    fractionOfDistanceBetweenInsertionPoints:NULL];
    objc_setAssociatedObject(self, &INDEX, @(index), OBJC_ASSOCIATION_RETAIN_NONATOMIC); // save index

    return (BOOL)[self.attributedText attribute:NSLinkAttributeName atIndex:index effectiveRange:NULL]; // tapped on part of a link?
}

- (void)openLink
{
    NSUInteger index = [objc_getAssociatedObject(self, &INDEX) unsignedIntegerValue]; // retrieve index
    NSURL *url = [self.attributedText attribute:NSLinkAttributeName atIndex:index effectiveRange:NULL];
    if (url && [UIApplication.sharedApplication canOpenURL:url]) [UIApplication.sharedApplication openURL:url];
}

@end 

这将通过一个UILabel子类(即没有objc_getAssociatedObject的混乱)来完成,但如果你像我一样,你更喜欢避免不必要的(第三方)子类,只是为了给现有的UIKit类添加一些额外的功能。此外,这有一个漂亮的地方,它添加了任何现有的UILabel的点击链接,例如现有的UITableViewCells!

我已经试着让它尽可能的最小化侵入性通过使用现有的NSLinkAttributeName属性在NSAttributedString中已经可用。所以很简单:

NSURL *myURL = [NSURL URLWithString:@"http://www.google.com"];
NSMutableAttributedString *myString = [NSMutableAttributedString.alloc initWithString:@"This string has a clickable link: "];
[myString appendAttributedString:[NSAttributedString.alloc initWithString:@"click here" attributes:@{NSLinkAttributeName:myURL}]];
...
myLabel.attributedText = myString;
myLabel.enableLinks = YES; // yes, that's all! :-)

基本上,它通过添加一个UIGestureRecognizer到你的UILabel来工作。最难的工作是在gestureRecognizerShouldBegin:中完成的,它会重新布局attributedText字符串,以找出被点击的字符。如果这个字符是NSLinkAttributeName的一部分,那么手势识别器将随后触发,检索相应的URL(从NSLinkAttributeName值),并打开每个通常的[UIApplication。sharedApplication openURL:url进程。

注意:通过在gestureRecognizerShouldBegin:中执行所有这些操作,如果你没有碰巧点击标签中的链接,事件就会被传递。因此,例如,你的UITableViewCell将捕获点击链接,但其他行为正常(选择单元格,取消选择,滚动,…)。

我把它放在了GitHub仓库里。 改编自Kai Burghardt的SO帖子。

其他回答

我找到了另一个解决方案:

我找到了一种方法来检测你从互联网上找到的html文本链接,你把它转换成nsattributeString:

func htmlAttributedString(fontSize: CGFloat = 17.0) -> NSAttributedString? {
            let fontName = UIFont.systemFont(ofSize: fontSize).fontName
            let string = self.appending(String(format: "<style>body{font-family: '%@'; font-size:%fpx;}</style>", fontName, fontSize))
            guard let data = string.data(using: String.Encoding.utf16, allowLossyConversion: false) else { return nil }

            guard let html = try? NSMutableAttributedString (
                data: data,
                options: [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html],
                documentAttributes: nil) else { return nil }
            return html
        }

我的方法允许您检测超链接,而无需指定它们。

first you create an extension of the tapgesturerecognizer : extension UITapGestureRecognizer { func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool { guard let attrString = label.attributedText else { return false } let layoutManager = NSLayoutManager() let textContainer = NSTextContainer(size: .zero) let textStorage = NSTextStorage(attributedString: attrString) layoutManager.addTextContainer(textContainer) textStorage.addLayoutManager(layoutManager) textContainer.lineFragmentPadding = 0 textContainer.lineBreakMode = label.lineBreakMode textContainer.maximumNumberOfLines = label.numberOfLines let labelSize = label.bounds.size textContainer.size = labelSize let locationOfTouchInLabel = self.location(in: label) let textBoundingBox = layoutManager.usedRect(for: textContainer) 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 = CGPoint(x: locationOfTouchInLabel.x - textContainerOffset.x, y: locationOfTouchInLabel.y - textContainerOffset.y) let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil) return NSLocationInRange(indexOfCharacter, targetRange) } }

然后在你的视图控制器中,你创建了一个url和范围列表来存储属性文本包含的所有链接和范围:

var listurl : [String] = []
    var listURLRange : [NSRange] = []

找到URL和URLRange,你可以使用:

    fun findLinksAndRange(attributeString : NSAttributeString){
        notification.enumerateAttribute(NSAttributedStringKey.link , in: NSMakeRange(0, notification.length), options: [.longestEffectiveRangeNotRequired]) { value, range, isStop in
                    if let value = value {
                        print("\(value) found at \(range.location)")
                        let stringValue = "\(value)"
                        listurl.append(stringValue)
                        listURLRange.append(range)
                    }
                }

            westlandNotifcationLabel.addGestureRecognizer(UITapGestureRecognizer(target : self, action: #selector(handleTapOnLabel(_:))))

    }

然后你实现了手柄tap:

@objc func handleTapOnLabel(_ recognizer: UITapGestureRecognizer) {
        for index in 0..<listURLRange.count{
            if recognizer.didTapAttributedTextInLabel(label: westlandNotifcationLabel, inRange: listURLRange[index]) {
                goToWebsite(url : listurl[index])
            }
        }
    }

    func goToWebsite(url : String){
        if let websiteUrl = URL(string: url){
            if #available(iOS 10, *) {
                UIApplication.shared.open(websiteUrl, options: [:],
                                          completionHandler: {
                                            (success) in
                                            print("Open \(websiteUrl): \(success)")
                })
            } else {
                let success = UIApplication.shared.openURL(websiteUrl)
                print("Open \(websiteUrl): \(success)")
            }
        }
    }

开始了!

我希望这个解决方案能帮助你,就像它帮助我一样。

我正在扩展@NAlexN原始的详细解决方案,与@zekel优秀的UITapGestureRecognizer扩展,并在Swift中提供。

Extending UITapGestureRecognizer

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 textStorage = NSTextStorage(attributedString: label.attributedText!)

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

        // Configure textContainer
        textContainer.lineFragmentPadding = 0.0
        textContainer.lineBreakMode = label.lineBreakMode
        textContainer.maximumNumberOfLines = label.numberOfLines
        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 = 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 = CGPoint(
            x: locationOfTouchInLabel.x - textContainerOffset.x,
            y: locationOfTouchInLabel.y - textContainerOffset.y
        )
        let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)

        return NSLocationInRange(indexOfCharacter, targetRange)
    }

}

使用

设置UIGestureRecognizer发送动作到tapLabel:,你可以检测目标范围是否在myLabel上被点击。

@IBAction func tapLabel(gesture: UITapGestureRecognizer) {
    if gesture.didTapAttributedTextInLabel(myLabel, inRange: targetRange1) {
        print("Tapped targetRange1")
    } else if gesture.didTapAttributedTextInLabel(myLabel, inRange: targetRange2) {
        print("Tapped targetRange2")
    } else {
        print("Tapped none")
    }
}

重要提示:UILabel换行模式必须设置为按word/char换行。以某种方式,只有当换行模式为其他模式时,NSTextContainer才会假定文本为单行。

用下面的.h和.m文件创建类。在.m文件中有以下函数

 - (void)linkAtPoint:(CGPoint)location

在这个函数中,我们将检查需要给予操作的子字符串的范围。使用你自己的逻辑来设置你的范围。

下面是子类的用法

TaggedLabel *label = [[TaggedLabel alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];
[self.view addSubview:label];
label.numberOfLines = 0;
NSMutableAttributedString *attributtedString = [[NSMutableAttributedString alloc] initWithString : @"My name is @jjpp" attributes : @{ NSFontAttributeName : [UIFont systemFontOfSize:10],}];                                                                                                                                                                              
//Do not forget to add the font attribute.. else it wont work.. it is very important
[attributtedString addAttribute:NSForegroundColorAttributeName
                        value:[UIColor redColor]
                        range:NSMakeRange(11, 5)];//you can give this range inside the .m function mentioned above

下面是.h文件

#import <UIKit/UIKit.h>

@interface TaggedLabel : UILabel<NSLayoutManagerDelegate>

@property(nonatomic, strong)NSLayoutManager *layoutManager;
@property(nonatomic, strong)NSTextContainer *textContainer;
@property(nonatomic, strong)NSTextStorage *textStorage;
@property(nonatomic, strong)NSArray *tagsArray;
@property(readwrite, copy) tagTapped nameTagTapped;

@end   

下面是.m文件

#import "TaggedLabel.h"
@implementation TaggedLabel

- (id)initWithFrame:(CGRect)frame
{
 self = [super initWithFrame:frame];
 if (self)
 {
  self.userInteractionEnabled = YES;
 }
return self;
}

- (id)initWithCoder:(NSCoder *)aDecoder
{
 self = [super initWithCoder:aDecoder];
if (self)
{
 self.userInteractionEnabled = YES;
}
return self;
}

- (void)setupTextSystem
{
 _layoutManager = [[NSLayoutManager alloc] init];
 _textContainer = [[NSTextContainer alloc] initWithSize:CGSizeZero];
 _textStorage = [[NSTextStorage alloc] initWithAttributedString:self.attributedText];
 // Configure layoutManager and textStorage
 [_layoutManager addTextContainer:_textContainer];
 [_textStorage addLayoutManager:_layoutManager];
 // Configure textContainer
 _textContainer.lineFragmentPadding = 0.0;
 _textContainer.lineBreakMode = NSLineBreakByWordWrapping;
 _textContainer.maximumNumberOfLines = 0;
 self.userInteractionEnabled = YES;
 self.textContainer.size = self.bounds.size;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
 if (!_layoutManager)
 {
  [self setupTextSystem];
 }
 // Get the info for the touched link if there is one
 CGPoint touchLocation = [[touches anyObject] locationInView:self];
 [self linkAtPoint:touchLocation];
}

- (void)linkAtPoint:(CGPoint)location
{
 // Do nothing if we have no text
 if (_textStorage.string.length == 0)
 {
  return;
 }
 // Work out the offset of the text in the view
 CGPoint textOffset = [self calcGlyphsPositionInView];
 // Get the touch location and use text offset to convert to text cotainer coords
 location.x -= textOffset.x;
 location.y -= textOffset.y;
 NSUInteger touchedChar = [_layoutManager glyphIndexForPoint:location inTextContainer:_textContainer];
 // If the touch is in white space after the last glyph on the line we don't
 // count it as a hit on the text
 NSRange lineRange;
 CGRect lineRect = [_layoutManager lineFragmentUsedRectForGlyphAtIndex:touchedChar effectiveRange:&lineRange];
 if (CGRectContainsPoint(lineRect, location) == NO)
 {
  return;
 }
 // Find the word that was touched and call the detection block
    NSRange range = NSMakeRange(11, 5);//for this example i'm hardcoding the range here. In a real scenario it should be iterated through an array for checking all the ranges
    if ((touchedChar >= range.location) && touchedChar < (range.location + range.length))
    {
     NSLog(@"range-->>%@",self.tagsArray[i][@"range"]);
    }
}

- (CGPoint)calcGlyphsPositionInView
{
 CGPoint textOffset = CGPointZero;
 CGRect textBounds = [_layoutManager usedRectForTextContainer:_textContainer];
 textBounds.size.width = ceil(textBounds.size.width);
 textBounds.size.height = ceil(textBounds.size.height);

 if (textBounds.size.height < self.bounds.size.height)
 {
  CGFloat paddingHeight = (self.bounds.size.height - textBounds.size.height) / 2.0;
  textOffset.y = paddingHeight;
 }

 if (textBounds.size.width < self.bounds.size.width)
 {
  CGFloat paddingHeight = (self.bounds.size.width - textBounds.size.width) / 2.0;
  textOffset.x = paddingHeight;
 }
 return textOffset;
 }

@end

(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);

}

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。