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
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)
其他回答
标签# Swift2.0
我从- excellent - @NAlexN的回答中获得灵感,我决定自己写一个UILabel的包装器。 我还尝试了TTTAttributedLabel,但我不能使它工作。
希望你能欣赏这段代码,欢迎任何建议!
import Foundation
@objc protocol TappableLabelDelegate {
optional func tappableLabel(tabbableLabel: TappableLabel, didTapUrl: NSURL, atRange: NSRange)
}
/// Represent a label with attributed text inside.
/// We can add a correspondence between a range of the attributed string an a link (URL)
/// By default, link will be open on the external browser @see 'openLinkOnExternalBrowser'
class TappableLabel: UILabel {
// MARK: - Public properties -
var links: NSMutableDictionary = [:]
var openLinkOnExternalBrowser = true
var delegate: TappableLabelDelegate?
// MARK: - Constructors -
override func awakeFromNib() {
super.awakeFromNib()
self.enableInteraction()
}
override init(frame: CGRect) {
super.init(frame: frame)
self.enableInteraction()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
private func enableInteraction() {
self.userInteractionEnabled = true
self.addGestureRecognizer(UITapGestureRecognizer(target: self, action: Selector("didTapOnLabel:")))
}
// MARK: - Public methods -
/**
Add correspondence between a range and a link.
- parameter url: url.
- parameter range: range on which couple url.
*/
func addLink(url url: String, atRange range: NSRange) {
self.links[url] = range
}
// MARK: - Public properties -
/**
Action rised on user interaction on label.
- parameter tapGesture: gesture.
*/
func didTapOnLabel(tapGesture: UITapGestureRecognizer) {
let labelSize = self.bounds.size;
let layoutManager = NSLayoutManager()
let textContainer = NSTextContainer(size: CGSizeZero)
let textStorage = NSTextStorage(attributedString: self.attributedText!)
// configure textContainer for the label
textContainer.lineFragmentPadding = 0
textContainer.lineBreakMode = self.lineBreakMode
textContainer.maximumNumberOfLines = self.numberOfLines
textContainer.size = labelSize;
// configure layoutManager and textStorage
layoutManager.addTextContainer(textContainer)
textStorage.addLayoutManager(layoutManager)
// find the tapped character location and compare it to the specified range
let locationOfTouchInLabel = tapGesture.locationInView(self)
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,
locationOfTouchInLabel.y - textContainerOffset.y)
let indexOfCharacter = layoutManager.characterIndexForPoint(locationOfTouchInTextContainer,
inTextContainer:textContainer,
fractionOfDistanceBetweenInsertionPoints: nil)
for (url, value) in self.links {
if let range = value as? NSRange {
if NSLocationInRange(indexOfCharacter, range) {
let url = NSURL(string: url as! String)!
if self.openLinkOnExternalBrowser {
UIApplication.sharedApplication().openURL(url)
}
self.delegate?.tappableLabel?(self, didTapUrl: url, atRange: range)
}
}
}
}
}
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
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")
}
}
}
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
}
}
}
}
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/"]];
}
}
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