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
翻译@samwize的扩展到Swift 4:
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)
}
}
要设置识别器(一旦你给文本和东西上色):
lblTermsOfUse.isUserInteractionEnabled = true
lblTermsOfUse.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleTapOnLabel(_:))))
...然后是手势识别器:
@objc func handleTapOnLabel(_ recognizer: UITapGestureRecognizer) {
guard let text = lblAgreeToTerms.attributedText?.string else {
return
}
if let range = text.range(of: NSLocalizedString("_onboarding_terms", comment: "terms")),
recognizer.didTapAttributedTextInLabel(label: lblAgreeToTerms, inRange: NSRange(range, in: text)) {
goToTermsAndConditions()
} else if let range = text.range(of: NSLocalizedString("_onboarding_privacy", comment: "privacy")),
recognizer.didTapAttributedTextInLabel(label: lblAgreeToTerms, inRange: NSRange(range, in: text)) {
goToPrivacyPolicy()
}
}
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/"]];
}
}
- (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);
}
我创建了一个名为ResponsiveLabel的UILabel子类,它是基于ios7中引入的textkit API。它使用了NAlexN建议的相同方法。它提供了在文本中指定搜索模式的灵活性。可以指定应用于这些模式的样式,以及在敲击模式时要执行的操作。
//Detects email in text
NSString *emailRegexString = @"[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,4}";
NSError *error;
NSRegularExpression *regex = [[NSRegularExpression alloc]initWithPattern:emailRegexString options:0 error:&error];
PatternDescriptor *descriptor = [[PatternDescriptor alloc]initWithRegex:regex withSearchType:PatternSearchTypeAll withPatternAttributes:@{NSForegroundColorAttributeName:[UIColor redColor]}];
[self.customLabel enablePatternDetection:descriptor];
如果你想让一个字符串可点击,你可以这样做。这段代码将属性应用到字符串“text”的每个出现处。
PatternTapResponder tapResponder = ^(NSString *string) {
NSLog(@"tapped = %@",string);
};
[self.customLabel enableStringDetection:@"text" withAttributes:@{NSForegroundColorAttributeName:[UIColor redColor],
RLTapResponderAttributeName: tapResponder}];
以下是基于@Luca Davanzo的回答,重写touchesBegan事件而不是轻触手势:
import UIKit
public protocol TapableLabelDelegate: NSObjectProtocol {
func tapableLabel(_ label: TapableLabel, didTapUrl url: String, atRange range: NSRange)
}
public class TapableLabel: UILabel {
private var links: [String: NSRange] = [:]
private(set) var layoutManager = NSLayoutManager()
private(set) var textContainer = NSTextContainer(size: CGSize.zero)
private(set) var textStorage = NSTextStorage() {
didSet {
textStorage.addLayoutManager(layoutManager)
}
}
public weak var delegate: TapableLabelDelegate?
public override var attributedText: NSAttributedString? {
didSet {
if let attributedText = attributedText {
textStorage = NSTextStorage(attributedString: attributedText)
} else {
textStorage = NSTextStorage()
links = [:]
}
}
}
public override var lineBreakMode: NSLineBreakMode {
didSet {
textContainer.lineBreakMode = lineBreakMode
}
}
public override var numberOfLines: Int {
didSet {
textContainer.maximumNumberOfLines = numberOfLines
}
}
public override init(frame: CGRect) {
super.init(frame: frame)
setup()
}
public required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
setup()
}
public override func layoutSubviews() {
super.layoutSubviews()
textContainer.size = bounds.size
}
/// addLinks
///
/// - Parameters:
/// - text: text of link
/// - url: link url string
public func addLink(_ text: String, withURL url: String) {
guard let theText = attributedText?.string as? NSString else {
return
}
let range = theText.range(of: text)
guard range.location != NSNotFound else {
return
}
links[url] = range
}
private func setup() {
isUserInteractionEnabled = true
layoutManager.addTextContainer(textContainer)
textContainer.lineFragmentPadding = 0
textContainer.lineBreakMode = lineBreakMode
textContainer.maximumNumberOfLines = numberOfLines
}
public override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
guard let locationOfTouch = touches.first?.location(in: self) else {
return
}
textContainer.size = bounds.size
let indexOfCharacter = layoutManager.glyphIndex(for: locationOfTouch, in: textContainer)
for (urlString, range) in links {
if NSLocationInRange(indexOfCharacter, range), let url = URL(string: urlString) {
delegate?.tapableLabel(self, didTapUrl: urlString, atRange: range)
}
}
}}
修改了@timbroder代码,以正确处理swift4.2的多行
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: 0 );
// Adjust for multiple lines of text
let lineModifier = Int(ceil(locationOfTouchInLabel.y / label.font.lineHeight)) - 1
let rightMostFirstLinePoint = CGPoint(x: labelSize.width, y: 0)
let charsPerLine = layoutManager.characterIndex(for: rightMostFirstLinePoint, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
let adjustedRange = indexOfCharacter + (lineModifier * charsPerLine)
var newTargetRange = targetRange
if lineModifier > 0 {
newTargetRange.location = targetRange.location+(lineModifier*Int(ceil(locationOfTouchInLabel.y)))
}
return NSLocationInRange(adjustedRange, newTargetRange)
}
}
UILabel代码
let tapAction = UITapGestureRecognizer(target: self, action: #selector(self.tapLabel(gesture:)))
let quote = "For full details please see our privacy policy and cookie policy."
let attributedString = NSMutableAttributedString(string: quote)
let string1: String = "privacy policy", string2: String = "cookie policy"
// privacy policy
let rangeString1 = quote.range(of: string1)!
let indexString1: Int = quote.distance(from: quote.startIndex, to: rangeString1.lowerBound)
attributedString.addAttributes(
[.font: <UIfont>,
.foregroundColor: <UI Color>,
.underlineStyle: 0, .underlineColor:UIColor.clear
], range: NSRange(location: indexString1, length: string1.count));
// cookie policy
let rangeString2 = quote.range(of: string2)!
let indexString2: Int = quote.distance(from: quote.startIndex, to: rangeString2.lowerBound )
attributedString.addAttributes(
[.font: <UIfont>,
.foregroundColor: <UI Color>,
.underlineStyle: 0, .underlineColor:UIColor.clear
], range: NSRange(location: indexString2, length: string2.count));
let label = UILabel()
label.frame = CGRect(x: 20, y: 200, width: 375, height: 100)
label.isUserInteractionEnabled = true
label.addGestureRecognizer(tapAction)
label.attributedText = attributedString
编码来识别水龙头
@objc
func tapLabel(gesture: UITapGestureRecognizer) {
if gesture.didTapAttributedTextInLabel(label: <UILabel>, inRange: termsLabelRange {
print("Terms of service")
} else if gesture.didTapAttributedTextInLabel(label:<UILabel> inRange: privacyPolicyLabelRange) {
print("Privacy policy")
} else {
print("Tapped none")
}
}
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