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
我扩展了@samwize的答案来处理多行UILabel,并给出了一个使用UIButton的例子
extension UITapGestureRecognizer {
func didTapAttributedTextInButton(button: UIButton, inRange targetRange: NSRange) -> Bool {
guard let label = button.titleLabel else { return false }
return didTapAttributedTextInLabel(label, inRange: targetRange)
}
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.locationInView(label)
let textBoundingBox = layoutManager.usedRectForTextContainer(textContainer)
let textContainerOffset = CGPointMake((labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x,
(labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y);
let locationOfTouchInTextContainer = CGPointMake((locationOfTouchInLabel.x - textContainerOffset.x),
0 );
// Adjust for multiple lines of text
let lineModifier = Int(ceil(locationOfTouchInLabel.y / label.font.lineHeight)) - 1
let rightMostFirstLinePoint = CGPointMake(labelSize.width, 0)
let charsPerLine = layoutManager.characterIndexForPoint(rightMostFirstLinePoint, inTextContainer: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
let indexOfCharacter = layoutManager.characterIndexForPoint(locationOfTouchInTextContainer, inTextContainer: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
let adjustedRange = indexOfCharacter + (lineModifier * charsPerLine)
return NSLocationInRange(adjustedRange, targetRange)
}
}
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/"]];
}
}
我很难处理这件事…带有链接的UILabel在带属性的文本上…这只是一个头痛,所以我最终使用ZSWTappableLabel。
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
}
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。
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。
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