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

老问题,但如果任何人都可以使用UITextView而不是UILabel,那就很容易了。标准网址,电话号码等将自动检测(并可点击)。

然而,如果你需要自定义检测,也就是说,如果你想在用户点击一个特定的单词后能够调用任何自定义方法,你需要使用NSAttributedStrings和一个NSLinkAttributeName属性,它将指向一个自定义URL方案(而不是在默认情况下使用http URL方案)。雷·温德里奇在这里报道

引用上述链接中的代码:

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:@"This is an example by @marcelofabri_"];
[attributedString addAttribute:NSLinkAttributeName
                     value:@"username://marcelofabri_"
                     range:[[attributedString string] rangeOfString:@"@marcelofabri_"]];

NSDictionary *linkAttributes = @{NSForegroundColorAttributeName: [UIColor greenColor],
                             NSUnderlineColorAttributeName: [UIColor lightGrayColor],
                             NSUnderlineStyleAttributeName: @(NSUnderlinePatternSolid)};

// assume that textView is a UITextView previously created (either by code or Interface Builder)
textView.linkTextAttributes = linkAttributes; // customizes the appearance of links
textView.attributedText = attributedString;
textView.delegate = self;

要检测这些链接点击,实现这个:

- (BOOL)textView:(UITextView *)textView shouldInteractWithURL:(NSURL *)URL inRange:(NSRange)characterRange {
    if ([[URL scheme] isEqualToString:@"username"]) {
        NSString *username = [URL host]; 
        // do something with this username
        // ...
        return NO;
    }
    return YES; // let the system open this URL
}

PS:确保你的UITextView是可选的。

其他回答

- (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);
}

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/"]];
    }
}

这里是一个Swift实现,它是尽可能少的,还包括触摸反馈。警告:

你必须在NSAttributedStrings中设置字体 你只能使用NSAttributedStrings! 你必须确保你的链接不能自动换行(使用不间断的空格:"\u{a0}") 设置文本后,不能更改lineBreakMode或numberolines 通过添加带有.link键的属性来创建链接

.

public class LinkLabel: UILabel {
    private var storage: NSTextStorage?
    private let textContainer = NSTextContainer()
    private let layoutManager = NSLayoutManager()
    private var selectedBackgroundView = UIView()

    override init(frame: CGRect) {
        super.init(frame: frame)
        textContainer.lineFragmentPadding = 0
        layoutManager.addTextContainer(textContainer)
        textContainer.layoutManager = layoutManager
        isUserInteractionEnabled = true
        selectedBackgroundView.isHidden = true
        selectedBackgroundView.backgroundColor = UIColor(white: 0, alpha: 0.3333)
        selectedBackgroundView.layer.cornerRadius = 4
        addSubview(selectedBackgroundView)
    }

    public required convenience init(coder: NSCoder) {
        self.init(frame: .zero)
    }

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

    public override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesBegan(touches, with: event)
        setLink(for: touches)
    }

    public override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesMoved(touches, with: event)
        setLink(for: touches)
    }

    private func setLink(for touches: Set<UITouch>) {
        if let pt = touches.first?.location(in: self), let (characterRange, _) = link(at: pt) {
            let glyphRange = layoutManager.glyphRange(forCharacterRange: characterRange, actualCharacterRange: nil)
            selectedBackgroundView.frame = layoutManager.boundingRect(forGlyphRange: glyphRange, in: textContainer).insetBy(dx: -3, dy: -3)
            selectedBackgroundView.isHidden = false
        } else {
            selectedBackgroundView.isHidden = true
        }
    }

    public override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesCancelled(touches, with: event)
        selectedBackgroundView.isHidden = true
    }

    public override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesEnded(touches, with: event)
        selectedBackgroundView.isHidden = true

        if let pt = touches.first?.location(in: self), let (_, url) = link(at: pt) {
            UIApplication.shared.open(url)
        }
    }

    private func link(at point: CGPoint) -> (NSRange, URL)? {
        let touchedGlyph = layoutManager.glyphIndex(for: point, in: textContainer)
        let touchedChar = layoutManager.characterIndexForGlyph(at: touchedGlyph)
        var range = NSRange()
        let attrs = attributedText!.attributes(at: touchedChar, effectiveRange: &range)
        if let urlstr = attrs[.link] as? String {
            return (range, URL(string: urlstr)!)
        } else {
            return nil
        }
    }

    public override var attributedText: NSAttributedString? {
        didSet {
            textContainer.maximumNumberOfLines = numberOfLines
            textContainer.lineBreakMode = lineBreakMode
            if let txt = attributedText {
                storage = NSTextStorage(attributedString: txt)
                storage!.addLayoutManager(layoutManager)
                layoutManager.textStorage = storage
                textContainer.size = frame.size
            }
        }
    }
}

UITextView支持OS3.0中的数据检测器,而UILabel不支持。

如果你在UITextView上启用了数据检测器,并且你的文本包含url、电话号码等,它们将以链接的形式出现。

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];
}