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。
其他回答
在Swift 3中工作,将整个代码粘贴在这里
//****Make sure the textview 'Selectable' = checked, and 'Editable = Unchecked'
import UIKit
class ViewController: UIViewController, UITextViewDelegate {
@IBOutlet var theNewTextView: UITextView!
override func viewDidLoad() {
super.viewDidLoad()
//****textview = Selectable = checked, and Editable = Unchecked
theNewTextView.delegate = self
let theString = NSMutableAttributedString(string: "Agree to Terms")
let theRange = theString.mutableString.range(of: "Terms")
theString.addAttribute(NSLinkAttributeName, value: "ContactUs://", range: theRange)
let theAttribute = [NSForegroundColorAttributeName: UIColor.blue, NSUnderlineStyleAttributeName: NSUnderlineStyle.styleSingle.rawValue] as [String : Any]
theNewTextView.linkTextAttributes = theAttribute
theNewTextView.attributedText = theString
theString.setAttributes(theAttribute, range: theRange)
}
func textView(_ textView: UITextView, shouldInteractWith URL: URL, in characterRange: NSRange, interaction: UITextItemInteraction) -> Bool {
if (URL.scheme?.hasPrefix("ContactUs://"))! {
return false //interaction not allowed
}
//*** Set storyboard id same as VC name
self.navigationController!.pushViewController((self.storyboard?.instantiateViewController(withIdentifier: "TheLastViewController"))! as UIViewController, animated: true)
return true
}
}
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。
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。
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。
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
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