在一个UILabel的NSAttributedString中创建可点击的“链接”?

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

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

2015-08-17 11:00:57

其他回答

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/"]];
    }
}

2015-02-14 19:17:16

(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);

}

2015-03-30 17:29:35

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。

2016-03-04 06:40:07

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。

2016-10-04 23:13:21