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

这是沙玛林。基于Kedar的答案的iOS c#实现。

MyClickableTextViewWithCustomUrlScheme实现与ShouldInteractWithUrl覆盖:

// Inspired from https://stackoverflow.com/a/44112932/15186
internal class MyClickableTextViewWithCustomUrlScheme : UITextView, IUITextViewDelegate
{
    public MyClickableTextViewWithCustomUrlScheme()
    {
        Initialize();
    }

    public MyClickableTextViewWithCustomUrlScheme(Foundation.NSCoder coder) : base(coder)
    {
        Initialize();
    }

    public MyClickableTextViewWithCustomUrlScheme(Foundation.NSObjectFlag t) : base(t)
    {
        Initialize();
    }

    public MyClickableTextViewWithCustomUrlScheme(IntPtr handle) : base(handle)
    {
        Initialize();
    }

    public MyClickableTextViewWithCustomUrlScheme(CoreGraphics.CGRect frame) : base(frame)
    {
        Initialize();
    }

    public MyClickableTextViewWithCustomUrlScheme(CoreGraphics.CGRect frame, NSTextContainer textContainer) : base(frame, textContainer)
    {
        Initialize();
    }

    void Initialize()
    {
        Delegate = this;
    }

    [Export("textView:shouldInteractWithURL:inRange:")]
    public new bool ShouldInteractWithUrl(UITextView textView, NSUrl URL, NSRange characterRange)
    {
        if (URL.Scheme.CompareTo(@"username") == 0)
        {
            // Launch the Activity
            return false;
        }
        // The system will handle the URL
        return base.ShouldInteractWithUrl(textView, URL, characterRange);
    }
}

在c#中转换的objective-C代码变成:

MyClickableTextViewWithCustomUrlScheme uiHabitTile = new MyClickableTextViewWithCustomUrlScheme();
uiHabitTile.Selectable = true;
uiHabitTile.ScrollEnabled = false;
uiHabitTile.Editable = false;

// https://stackoverflow.com/a/34014655/15186
string wholeTitle = @"This is an example by marcelofabri";

NSMutableAttributedString attributedString = new NSMutableAttributedString(wholeTitle);
attributedString.AddAttribute(UIStringAttributeKey.Link,
   new NSString("username://marcelofabri"),
   attributedString.Value.RangeOfString(@"marcelofabri")
);
NSMutableDictionary<NSString, NSObject> linkAttributes = new NSMutableDictionary<NSString, NSObject>();
linkAttributes[UIStringAttributeKey.ForegroundColor] = UIColor.Green;
linkAttributes[UIStringAttributeKey.UnderlineColor] = UIColor.LightGray;
linkAttributes[UIStringAttributeKey.UnderlineStyle] = new NSNumber((short)NSUnderlineStyle.PatternSolid);

uiHabitTile.AttributedText = attributedString;

确保将Editable = false和Selectable = true设置为能够单击链接。

同样,ScrollEnabled = true允许textview正确地调整其高度大小。

其他回答

(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。

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
            }
        }
    }
}

Drop-in解决方案作为UILabel上的一个类别(这假设你的UILabel使用一个带有NSLinkAttributeName属性的带属性字符串):

@implementation UILabel (Support)

- (BOOL)openTappedLinkAtLocation:(CGPoint)location {
  CGSize labelSize = self.bounds.size;

  NSTextContainer* textContainer = [[NSTextContainer alloc] initWithSize:CGSizeZero];
  textContainer.lineFragmentPadding = 0.0;
  textContainer.lineBreakMode = self.lineBreakMode;
  textContainer.maximumNumberOfLines = self.numberOfLines;
  textContainer.size = labelSize;

  NSLayoutManager* layoutManager = [[NSLayoutManager alloc] init];
  [layoutManager addTextContainer:textContainer];

  NSTextStorage* textStorage = [[NSTextStorage alloc] initWithAttributedString:self.attributedText];
  [textStorage addAttribute:NSFontAttributeName value:self.font range:NSMakeRange(0, textStorage.length)];
  [textStorage addLayoutManager:layoutManager];

  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(location.x - textContainerOffset.x, location.y - textContainerOffset.y);
  NSInteger indexOfCharacter = [layoutManager characterIndexForPoint:locationOfTouchInTextContainer inTextContainer:textContainer fractionOfDistanceBetweenInsertionPoints:nullptr];
  if (indexOfCharacter >= 0) {
    NSURL* url = [textStorage attribute:NSLinkAttributeName atIndex:indexOfCharacter effectiveRange:nullptr];
    if (url) {
      [[UIApplication sharedApplication] openURL:url];
      return YES;
    }
  }
  return NO;
}

@end

最简单可靠的方法是使用Kedar Paranjape推荐的UITextView。基于Karl Nosworthy的回答,我最终想出了一个简单的UITextView子类:

class LinkTextView: UITextView, UITextViewDelegate {
    
    typealias Links = [String: String]
    
    typealias OnLinkTap = (URL) -> Bool
    
    var onLinkTap: OnLinkTap?
    
    override init(frame: CGRect, textContainer: NSTextContainer?) {
        super.init(frame: frame, textContainer: textContainer)
        isEditable = false
        isSelectable = true
        isScrollEnabled = false //to have own size and behave like a label
        delegate = self
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }
    
    func addLinks(_ links: Links) {
        guard attributedText.length > 0  else {
            return
        }
        let mText = NSMutableAttributedString(attributedString: attributedText)
        
        for (linkText, urlString) in links {
            if linkText.count > 0 {
                let linkRange = mText.mutableString.range(of: linkText)
                mText.addAttribute(.link, value: urlString, range: linkRange)
            }
        }
        attributedText = mText
    }
    
    func textView(_ textView: UITextView, shouldInteractWith URL: URL, in characterRange: NSRange) -> Bool {
        return onLinkTap?(URL) ?? true
    }
    
    // to disable text selection
    func textViewDidChangeSelection(_ textView: UITextView) {
        textView.selectedTextRange = nil
    }
}

用法非常简单:

    let linkTextView = LinkTextView()
    let tu = "Terms of Use"
    let pp = "Privacy Policy"
    linkTextView.text = "Please read the Some Company \(tu) and \(pp)"
    linkTextView.addLinks([
        tu: "https://some.com/tu",
        pp: "https://some.com/pp"
    ])
    linkTextView.onLinkTap = { url in
        print("url: \(url)")
        return true
    }

请注意,isScrollEnabled默认为false,因为在大多数情况下,我们需要有自己大小且没有滚动的类似标签的小视图。如果你想要一个可滚动的文本视图,就把它设为true。

还要注意,UITextView不像UILabel有默认的文本填充。要删除它,使布局与UILabel相同,只需添加:linkTextView。textContainerInset = . 0

实现onLinkTap闭包是不必要的,没有它url是由UIApplication自动打开的。

由于文本选择在大多数情况下是不可取的,但它不能关闭,它在委托方法中被解散(感谢Carson Vo)