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
这是沙玛林。基于Kedar的答案的iOS c#实现。
MyClickableTextViewWithCustomUrlScheme实现与ShouldInteractWithUrl覆盖:
// Inspired from https://stackoverflow.com/a/44112932/15186
internal class MyClickableTextViewWithCustomUrlScheme : UITextView, IUITextViewDelegate
{
public MyClickableTextViewWithCustomUrlScheme()
{
Initialize();
}
public MyClickableTextViewWithCustomUrlScheme(Foundation.NSCoder coder) : base(coder)
{
Initialize();
}
public MyClickableTextViewWithCustomUrlScheme(Foundation.NSObjectFlag t) : base(t)
{
Initialize();
}
public MyClickableTextViewWithCustomUrlScheme(IntPtr handle) : base(handle)
{
Initialize();
}
public MyClickableTextViewWithCustomUrlScheme(CoreGraphics.CGRect frame) : base(frame)
{
Initialize();
}
public MyClickableTextViewWithCustomUrlScheme(CoreGraphics.CGRect frame, NSTextContainer textContainer) : base(frame, textContainer)
{
Initialize();
}
void Initialize()
{
Delegate = this;
}
[Export("textView:shouldInteractWithURL:inRange:")]
public new bool ShouldInteractWithUrl(UITextView textView, NSUrl URL, NSRange characterRange)
{
if (URL.Scheme.CompareTo(@"username") == 0)
{
// Launch the Activity
return false;
}
// The system will handle the URL
return base.ShouldInteractWithUrl(textView, URL, characterRange);
}
}
在c#中转换的objective-C代码变成:
MyClickableTextViewWithCustomUrlScheme uiHabitTile = new MyClickableTextViewWithCustomUrlScheme();
uiHabitTile.Selectable = true;
uiHabitTile.ScrollEnabled = false;
uiHabitTile.Editable = false;
// https://stackoverflow.com/a/34014655/15186
string wholeTitle = @"This is an example by marcelofabri";
NSMutableAttributedString attributedString = new NSMutableAttributedString(wholeTitle);
attributedString.AddAttribute(UIStringAttributeKey.Link,
new NSString("username://marcelofabri"),
attributedString.Value.RangeOfString(@"marcelofabri")
);
NSMutableDictionary<NSString, NSObject> linkAttributes = new NSMutableDictionary<NSString, NSObject>();
linkAttributes[UIStringAttributeKey.ForegroundColor] = UIColor.Green;
linkAttributes[UIStringAttributeKey.UnderlineColor] = UIColor.LightGray;
linkAttributes[UIStringAttributeKey.UnderlineStyle] = new NSNumber((short)NSUnderlineStyle.PatternSolid);
uiHabitTile.AttributedText = attributedString;
确保将Editable = false和Selectable = true设置为能够单击链接。
同样,ScrollEnabled = true允许textview正确地调整其高度大小。
其他回答
我强烈建议使用自动检测文本中的url并将其转换为链接的库。 试一试:
TTTAttributedLabel (pod) ZSWTappableLabel (under).
两者都得到了麻省理工学院的许可。
斯威夫特5.2
我在之前的回答中发现了多行文本标签的几个问题,所以我给出了我最终的工作解决方案。
它解决了多行和文本对齐的问题。
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 textAligmentOffset = aligmentOffset(for: label)
let textContainerOffset = CGPoint(x: (labelSize.width - textBoundingBox.size.width) * textAligmentOffset - textBoundingBox.origin.x,
y: (labelSize.height - textBoundingBox.size.height) * textAligmentOffset - textBoundingBox.origin.y)
let locationOfTouchInTextContainer = CGPoint(x: (locationOfTouchInLabel.x - textContainerOffset.x),
y: 0 )
// Adjust for multiple lines of text
let lineModifier = Int(floor(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)
return NSLocationInRange(adjustedRange, targetRange)
}
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
}
}
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。
- (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);
}
这是一个Objective-C类别,它支持现有UILabel中的可点击链接。attributedText字符串,利用现有的NSLinkAttributeName属性。
@interface UILabel (GSBClickableLinks) <UIGestureRecognizerDelegate>
@property BOOL enableLinks;
@end
#import <objc/runtime.h>
static const void *INDEX;
static const void *TAP;
@implementation UILabel (GSBClickableLinks)
- (void)setEnableLinks:(BOOL)enableLinks
{
UITapGestureRecognizer *tap = objc_getAssociatedObject(self, &TAP); // retreive tap
if (enableLinks && !tap) { // add a gestureRegonzier to the UILabel to detect taps
tap = [UITapGestureRecognizer.alloc initWithTarget:self action:@selector(openLink)];
tap.delegate = self;
[self addGestureRecognizer:tap];
objc_setAssociatedObject(self, &TAP, tap, OBJC_ASSOCIATION_RETAIN_NONATOMIC); // save tap
}
self.userInteractionEnabled = enableLinks; // note - when false UILAbel wont receive taps, hence disable links
}
- (BOOL)enableLinks
{
return (BOOL)objc_getAssociatedObject(self, &TAP); // ie tap != nil
}
// First check whether user tapped on a link within the attributedText of the label.
// If so, then the our label's gestureRecogizer will subsequently fire, and open the corresponding NSLinkAttributeName.
// If not, then the tap will get passed along, eg to the enclosing UITableViewCell...
// Note: save which character in the attributedText was clicked so that we dont have to redo everything again in openLink.
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
if (gestureRecognizer != objc_getAssociatedObject(self, &TAP)) return YES; // dont block other gestures (eg swipe)
// Re-layout the attributedText to find out what was tapped
NSTextContainer *textContainer = [NSTextContainer.alloc initWithSize:self.frame.size];
textContainer.lineFragmentPadding = 0;
textContainer.maximumNumberOfLines = self.numberOfLines;
textContainer.lineBreakMode = self.lineBreakMode;
NSLayoutManager *layoutManager = NSLayoutManager.new;
[layoutManager addTextContainer:textContainer];
NSTextStorage *textStorage = [NSTextStorage.alloc initWithAttributedString:self.attributedText];
[textStorage addLayoutManager:layoutManager];
NSUInteger index = [layoutManager characterIndexForPoint:[gestureRecognizer locationInView:self]
inTextContainer:textContainer
fractionOfDistanceBetweenInsertionPoints:NULL];
objc_setAssociatedObject(self, &INDEX, @(index), OBJC_ASSOCIATION_RETAIN_NONATOMIC); // save index
return (BOOL)[self.attributedText attribute:NSLinkAttributeName atIndex:index effectiveRange:NULL]; // tapped on part of a link?
}
- (void)openLink
{
NSUInteger index = [objc_getAssociatedObject(self, &INDEX) unsignedIntegerValue]; // retrieve index
NSURL *url = [self.attributedText attribute:NSLinkAttributeName atIndex:index effectiveRange:NULL];
if (url && [UIApplication.sharedApplication canOpenURL:url]) [UIApplication.sharedApplication openURL:url];
}
@end
这将通过一个UILabel子类(即没有objc_getAssociatedObject的混乱)来完成,但如果你像我一样,你更喜欢避免不必要的(第三方)子类,只是为了给现有的UIKit类添加一些额外的功能。此外,这有一个漂亮的地方,它添加了任何现有的UILabel的点击链接,例如现有的UITableViewCells!
我已经试着让它尽可能的最小化侵入性通过使用现有的NSLinkAttributeName属性在NSAttributedString中已经可用。所以很简单:
NSURL *myURL = [NSURL URLWithString:@"http://www.google.com"];
NSMutableAttributedString *myString = [NSMutableAttributedString.alloc initWithString:@"This string has a clickable link: "];
[myString appendAttributedString:[NSAttributedString.alloc initWithString:@"click here" attributes:@{NSLinkAttributeName:myURL}]];
...
myLabel.attributedText = myString;
myLabel.enableLinks = YES; // yes, that's all! :-)
基本上,它通过添加一个UIGestureRecognizer到你的UILabel来工作。最难的工作是在gestureRecognizerShouldBegin:中完成的,它会重新布局attributedText字符串,以找出被点击的字符。如果这个字符是NSLinkAttributeName的一部分,那么手势识别器将随后触发,检索相应的URL(从NSLinkAttributeName值),并打开每个通常的[UIApplication。sharedApplication openURL:url进程。
注意:通过在gestureRecognizerShouldBegin:中执行所有这些操作,如果你没有碰巧点击标签中的链接,事件就会被传递。因此,例如,你的UITableViewCell将捕获点击链接,但其他行为正常(选择单元格,取消选择,滚动,…)。
我把它放在了GitHub仓库里。 改编自Kai Burghardt的SO帖子。
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