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);
}
其他回答
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。
有些答案并不如我所料。这是Swift解决方案,也支持textAlignment和多行。不需要子类化,只是这个UITapGestureRecognizer扩展:
import UIKit
extension UITapGestureRecognizer {
func didTapAttributedString(_ string: String, in label: UILabel) -> Bool {
guard let text = label.text else {
return false
}
let range = (text as NSString).range(of: string)
return self.didTapAttributedText(label: label, inRange: range)
}
private func didTapAttributedText(label: UILabel, inRange targetRange: NSRange) -> Bool {
guard let attributedText = label.attributedText else {
assertionFailure("attributedText must be set")
return false
}
let textContainer = createTextContainer(for: label)
let layoutManager = NSLayoutManager()
layoutManager.addTextContainer(textContainer)
let textStorage = NSTextStorage(attributedString: attributedText)
if let font = label.font {
textStorage.addAttribute(NSAttributedString.Key.font, value: font, range: NSMakeRange(0, attributedText.length))
}
textStorage.addLayoutManager(layoutManager)
let locationOfTouchInLabel = location(in: label)
let textBoundingBox = layoutManager.usedRect(for: textContainer)
let alignmentOffset = aligmentOffset(for: label)
let xOffset = ((label.bounds.size.width - textBoundingBox.size.width) * alignmentOffset) - textBoundingBox.origin.x
let yOffset = ((label.bounds.size.height - textBoundingBox.size.height) * alignmentOffset) - textBoundingBox.origin.y
let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x - xOffset, y: locationOfTouchInLabel.y - yOffset)
let characterTapped = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
let lineTapped = Int(ceil(locationOfTouchInLabel.y / label.font.lineHeight)) - 1
let rightMostPointInLineTapped = CGPoint(x: label.bounds.size.width, y: label.font.lineHeight * CGFloat(lineTapped))
let charsInLineTapped = layoutManager.characterIndex(for: rightMostPointInLineTapped, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
return characterTapped < charsInLineTapped ? targetRange.contains(characterTapped) : false
}
private func createTextContainer(for label: UILabel) -> NSTextContainer {
let textContainer = NSTextContainer(size: label.bounds.size)
textContainer.lineFragmentPadding = 0.0
textContainer.lineBreakMode = label.lineBreakMode
textContainer.maximumNumberOfLines = label.numberOfLines
return textContainer
}
private func aligmentOffset(for label: UILabel) -> CGFloat {
switch label.textAlignment {
case .left, .natural, .justified:
return 0.0
case .center:
return 0.5
case .right:
return 1.0
@unknown default:
return 0.0
}
}
}
用法:
class ViewController: UIViewController {
@IBOutlet var label : UILabel!
let selectableString1 = "consectetur"
let selectableString2 = "cupidatat"
override func viewDidLoad() {
super.viewDidLoad()
let text = "Lorem ipsum dolor sit amet, \(selectableString1) adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat \(selectableString2) non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."
label.attributedText = NSMutableAttributedString(attributedString: NSAttributedString(string: text))
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(labelTapped))
label.addGestureRecognizer(tapGesture)
label.isUserInteractionEnabled = true
}
@objc func labelTapped(gesture: UITapGestureRecognizer) {
if gesture.didTapAttributedString(selectableString1, in: label) {
print("\(selectableString1) tapped")
} else if gesture.didTapAttributedString(selectableString2, in: label) {
print("\(selectableString2) tapped")
} else {
print("Text tapped")
}
}
}
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。
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
}
}
}
}
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)
}
}
}}
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