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

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/"]];
    }
}

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
}
- (BOOL)didTapAttributedTextInLabel:(UILabel *)label inRange:(NSRange)targetRange{
    NSLayoutManager *layoutManager = [NSLayoutManager new];
    NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:CGSizeZero];
    NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:label.attributedText];

    [layoutManager addTextContainer:textContainer];
    [textStorage addLayoutManager:layoutManager];

    textContainer.lineFragmentPadding = 0.0;
    textContainer.lineBreakMode = label.lineBreakMode;
    textContainer.maximumNumberOfLines = label.numberOfLines;
    CGSize labelSize = label.bounds.size;
    textContainer.size = labelSize;

    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);
    NSUInteger indexOfCharacter =[layoutManager characterIndexForPoint:locationOfTouchInTextContainer inTextContainer:textContainer fractionOfDistanceBetweenInsertionPoints:nil];

    return NSLocationInRange(indexOfCharacter, targetRange);
}

下面是超链接UILabel的示例代码: 来源:http://sickprogrammersarea.blogspot.in/2014/03/adding-links-to-uilabel.html

#import "ViewController.h"
#import "TTTAttributedLabel.h"

@interface ViewController ()
@end

@implementation ViewController
{
    UITextField *loc;
    TTTAttributedLabel *data;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    UILabel *lbl = [[UILabel alloc] initWithFrame:CGRectMake(5, 20, 80, 25) ];
    [lbl setText:@"Text:"];
    [lbl setFont:[UIFont fontWithName:@"Verdana" size:16]];
    [lbl setTextColor:[UIColor grayColor]];
    loc=[[UITextField alloc] initWithFrame:CGRectMake(4, 20, 300, 30)];
    //loc.backgroundColor = [UIColor grayColor];
    loc.borderStyle=UITextBorderStyleRoundedRect;
    loc.clearButtonMode=UITextFieldViewModeWhileEditing;
    //[loc setText:@"Enter Location"];
    loc.clearsOnInsertion = YES;
    loc.leftView=lbl;
    loc.leftViewMode=UITextFieldViewModeAlways;
    [loc setDelegate:self];
    [self.view addSubview:loc];
    [loc setRightViewMode:UITextFieldViewModeAlways];
    CGRect frameimg = CGRectMake(110, 70, 70,30);
    UIButton *srchButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    srchButton.frame=frameimg;
    [srchButton setTitle:@"Go" forState:UIControlStateNormal];
    [srchButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    srchButton.backgroundColor=[UIColor clearColor];
    [srchButton addTarget:self action:@selector(go:) forControlEvents:UIControlEventTouchDown];
    [self.view addSubview:srchButton];
    data = [[TTTAttributedLabel alloc] initWithFrame:CGRectMake(5, 120,self.view.frame.size.width,200) ];
    [data setFont:[UIFont fontWithName:@"Verdana" size:16]];
    [data setTextColor:[UIColor blackColor]];
    data.numberOfLines=0;
    data.delegate = self;
    data.enabledTextCheckingTypes=NSTextCheckingTypeLink|NSTextCheckingTypePhoneNumber;
    [self.view addSubview:data];
}
- (void)attributedLabel:(TTTAttributedLabel *)label didSelectLinkWithURL:(NSURL *)url
{
    NSString *val=[[NSString alloc]initWithFormat:@"%@",url];
    if ([[url scheme] hasPrefix:@"mailto"]) {
              NSLog(@" mail URL Selected : %@",url);
        MFMailComposeViewController *comp=[[MFMailComposeViewController alloc]init];
        [comp setMailComposeDelegate:self];
        if([MFMailComposeViewController canSendMail])
        {
            NSString *recp=[[val substringToIndex:[val length]] substringFromIndex:7];
            NSLog(@"Recept : %@",recp);
            [comp setToRecipients:[NSArray arrayWithObjects:recp, nil]];
            [comp setSubject:@"From my app"];
            [comp setMessageBody:@"Hello bro" isHTML:NO];
            [comp setModalTransitionStyle:UIModalTransitionStyleCrossDissolve];
            [self presentViewController:comp animated:YES completion:nil];
        }
    }
    else{
        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:val]];
    }
}
-(void)mailComposeController:(MFMailComposeViewController *)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError *)error{
    if(error)
    {
        UIAlertView *alrt=[[UIAlertView alloc]initWithTitle:@"Erorr" message:@"Some error occureed" delegate:nil cancelButtonTitle:@"" otherButtonTitles:nil, nil];
        [alrt show];
        [self dismissViewControllerAnimated:YES completion:nil];
    }
    else{
        [self dismissViewControllerAnimated:YES completion:nil];
    }
}

- (void)attributedLabel:(TTTAttributedLabel *)label didSelectLinkWithPhoneNumber:(NSString *)phoneNumber
{
    NSLog(@"Phone Number Selected : %@",phoneNumber);
    UIDevice *device = [UIDevice currentDevice];
    if ([[device model] isEqualToString:@"iPhone"] ) {
        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:[NSString stringWithFormat:@"tel:%@",phoneNumber]]];
    } else {
        UIAlertView *Notpermitted=[[UIAlertView alloc] initWithTitle:@"Alert" message:@"Your device doesn't support this feature." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
        [Notpermitted show];
    }
}
-(void)go:(id)sender
{
    [data setText:loc.text];
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSLog(@"Reached");
    [loc resignFirstResponder];
}

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。