有没有一种简单的方法可以从 UILabel 中的给定行获取（或简单地显示）文本？
我的 UILabel 正确地显示了我的文本并将其布置得很漂亮，但有时我需要能够只显示某些行，但显然我需要知道 UILabel 是如何定位所有内容来做到这一点的。
我知道这可以通过子字符串轻松完成，但我需要知道该行的起点和终点。
或者，如果 UILabel 的框架有某种偏移，我可以滚动 UILabel 并隐藏我不想看到的其余内容。
我无法发现任何表明如何轻松做到这一点的东西。有人有什么好主意吗？
谢谢
伊帕奥
问问题
15233 次
10 回答
32
我有更好的方法找到它。
你可以在CoreText.framework的帮助下得到这个。
1.添加CoreText.framework 。
2.进口#import <CoreText/CoreText.h>。
然后使用以下方法：
- (NSArray *)getLinesArrayOfStringInLabel:(UILabel *)label {
NSString *text = [label text];
UIFont *font = [label font];
CGRect rect = [label frame];
CTFontRef myFont = CTFontCreateWithName((__bridge CFStringRef)([font fontName]), [font pointSize], NULL);
NSMutableAttributedString *attStr = [[NSMutableAttributedString alloc] initWithString:text];
[attStr addAttribute:(NSString *)kCTFontAttributeName value:(__bridge id)myFont range:NSMakeRange(0, attStr.length)];
CTFramesetterRef frameSetter = CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)attStr);
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, CGRectMake(0,0,rect.size.width,100000));
CTFrameRef frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, NULL);
NSArray *lines = (__bridge NSArray *)CTFrameGetLines(frame);
NSMutableArray *linesArray = [[NSMutableArray alloc]init];
for (id line in lines)
{
CTLineRef lineRef = (__bridge CTLineRef )line;
CFRange lineRange = CTLineGetStringRange(lineRef);
NSRange range = NSMakeRange(lineRange.location, lineRange.length);
NSString *lineString = [text substringWithRange:range];
[linesArray addObject:lineString];
}
return (NSArray *)linesArray;
}
调用此方法：-
NSArray *linesArray = [self getLinesArrayOfStringInLabel:yourLabel];
现在您可以使用linesArray.
斯威夫特 4 版
func getLinesArrayOfString(in label: UILabel) -> [String] {
/// An empty string's array
var linesArray = [String]()
guard let text = label.text, let font = label.font else {return linesArray}
let rect = label.frame
let myFont = CTFontCreateWithFontDescriptor(font.fontDescriptor, 0, nil)
let attStr = NSMutableAttributedString(string: text)
attStr.addAttribute(kCTFontAttributeName as NSAttributedString.Key, value: myFont, range: NSRange(location: 0, length: attStr.length))
let frameSetter: CTFramesetter = CTFramesetterCreateWithAttributedString(attStr as CFAttributedString)
let path: CGMutablePath = CGMutablePath()
path.addRect(CGRect(x: 0, y: 0, width: rect.size.width, height: 100000), transform: .identity)
let frame: CTFrame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, nil)
guard let lines = CTFrameGetLines(frame) as? [Any] else {return linesArray}
for line in lines {
let lineRef = line as! CTLine
let lineRange: CFRange = CTLineGetStringRange(lineRef)
let range = NSRange(location: lineRange.location, length: lineRange.length)
let lineString: String = (text as NSString).substring(with: range)
linesArray.append(lineString)
}
return linesArray
}
利用：
let lines: [String] = getLinesArrayOfString(in: label)
于 2013-01-19T10:42:23.050 回答
9
斯威夫特 3
func getLinesArrayFromLabel(label:UILabel) -> [String] {
let text:NSString = label.text! as NSString // TODO: Make safe?
let font:UIFont = label.font
let rect:CGRect = label.frame
let myFont:CTFont = CTFontCreateWithName(font.fontName as CFString, font.pointSize, nil)
let attStr:NSMutableAttributedString = NSMutableAttributedString(string: text as String)
attStr.addAttribute(String(kCTFontAttributeName), value:myFont, range: NSMakeRange(0, attStr.length))
let frameSetter:CTFramesetter = CTFramesetterCreateWithAttributedString(attStr as CFAttributedString)
let path:CGMutablePath = CGMutablePath()
path.addRect(CGRect(x:0, y:0, width:rect.size.width, height:100000))
let frame:CTFrame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, nil)
let lines = CTFrameGetLines(frame) as NSArray
var linesArray = [String]()
for line in lines {
let lineRange = CTLineGetStringRange(line as! CTLine)
let range:NSRange = NSMakeRange(lineRange.location, lineRange.length)
let lineString = text.substring(with: range)
linesArray.append(lineString as String)
}
return linesArray
}
Swift 2 (Xcode 7) 版本（经过测试，并从 Swift 1 答案重新编辑）
func getLinesArrayOfStringInLabel(label:UILabel) -> [String] {
let text:NSString = label.text! // TODO: Make safe?
let font:UIFont = label.font
let rect:CGRect = label.frame
let myFont:CTFontRef = CTFontCreateWithName(font.fontName, font.pointSize, nil)
let attStr:NSMutableAttributedString = NSMutableAttributedString(string: text as String)
attStr.addAttribute(String(kCTFontAttributeName), value:myFont, range: NSMakeRange(0, attStr.length))
let frameSetter:CTFramesetterRef = CTFramesetterCreateWithAttributedString(attStr as CFAttributedStringRef)
let path:CGMutablePathRef = CGPathCreateMutable()
CGPathAddRect(path, nil, CGRectMake(0, 0, rect.size.width, 100000))
let frame:CTFrameRef = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, nil)
let lines = CTFrameGetLines(frame) as NSArray
var linesArray = [String]()
for line in lines {
let lineRange = CTLineGetStringRange(line as! CTLine)
let range:NSRange = NSMakeRange(lineRange.location, lineRange.length)
let lineString = text.substringWithRange(range)
linesArray.append(lineString as String)
}
return linesArray
}
于 2015-06-30T02:04:21.360 回答
5
以适当的释放回答！！！！
-(NSArray *)getLinesArrayOfStringInLabel:(UILabel *)label
{
NSString *text = [label text];
UIFont *font = [label font];
CGRect rect = [label frame];
CTFontRef myFont = CTFontCreateWithName(( CFStringRef)([font fontName]), [font pointSize], NULL);
NSMutableAttributedString *attStr = [[NSMutableAttributedString alloc] initWithString:text];
[attStr addAttribute:(NSString *)kCTFontAttributeName value:( id)myFont range:NSMakeRange(0, attStr.length)];
CFRelease(myFont);
CTFramesetterRef frameSetter = CTFramesetterCreateWithAttributedString(( CFAttributedStringRef)attStr);
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, CGRectMake(0,0,rect.size.width,100000));
CTFrameRef frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, NULL);
NSArray *lines = ( NSArray *)CTFrameGetLines(frame);
NSMutableArray *linesArray = [[NSMutableArray alloc]init];
for (id line in lines)
{
CTLineRef lineRef = ( CTLineRef )line;
CFRange lineRange = CTLineGetStringRange(lineRef);
NSRange range = NSMakeRange(lineRange.location, lineRange.length);
NSString *lineString = [text substringWithRange:range];
CFAttributedStringSetAttribute((CFMutableAttributedStringRef)attStr, lineRange, kCTKernAttributeName, (CFTypeRef)([NSNumber numberWithFloat:0.0]));
CFAttributedStringSetAttribute((CFMutableAttributedStringRef)attStr, lineRange, kCTKernAttributeName, (CFTypeRef)([NSNumber numberWithInt:0.0]));
//NSLog(@"''''''''''''''''''%@",lineString);
[linesArray addObject:lineString];
}
[attStr release];
CGPathRelease(path);
CFRelease( frame );
CFRelease(frameSetter);
return (NSArray *)linesArray;
}
于 2013-02-19T08:28:01.517 回答
5
关于 iOS 11+ 的非常重要的变化
从 iOS 11 开始，Apple 有意更改了其自动换行功能的行为，UILabel该功能会检测String多行中各行的内容UILabel。按照设计，UILabel现在的自动换行避免了孤立文本（换行中的单个单词），如下所述：iOS 11 中的自动换行
因此，如果避免孤立文本的新自动换行在特定行中生效，则CTFrameGetLines(frame)返回CTLine标签中所有行的数组的方式将不再正常工作。相反，它导致String新的自动换行设计的部分内容属于下一行，而不是最终在焦点行中。
可以在我的@TheTiger's answer 的更改版本中找到针对此问题的经过测试的修复程序，该版本使用计算UILabelusing的实际内容大小sizeThatFits(size:)，然后使用该大小创建用Swift 4编写的 rect / 路径：
extension UILabel {
/// creates an array containing one entry for each line of text the label has
var lines: [String]? {
guard let text = text, let font = font else { return nil }
let attStr = NSMutableAttributedString(string: text)
attStr.addAttribute(NSAttributedString.Key.font, value: font, range: NSRange(location: 0, length: attStr.length))
let frameSetter = CTFramesetterCreateWithAttributedString(attStr as CFAttributedString)
let path = CGMutablePath()
// size needs to be adjusted, because frame might change because of intelligent word wrapping of iOS
let size = sizeThatFits(CGSize(width: self.frame.width, height: .greatestFiniteMagnitude))
path.addRect(CGRect(x: 0, y: 0, width: size.width, height: size.height), transform: .identity)
let frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, attStr.length), path, nil)
guard let lines = CTFrameGetLines(frame) as? [Any] else { return nil }
var linesArray: [String] = []
for line in lines {
let lineRef = line as! CTLine
let lineRange = CTLineGetStringRange(lineRef)
let range = NSRange(location: lineRange.location, length: lineRange.length)
let lineString = (text as NSString).substring(with: range)
linesArray.append(lineString)
}
return linesArray
}
}
此UILabel扩展将标签的内容作为String数组返回，每行一个条目与呈现给用户的外观完全相同。
于 2018-12-14T16:06:06.733 回答
4
我不认为有这样做的本地方法（如“takethenline”方法）。
我可以找出一个棘手的解决方案，但我不确定是最好的解决方案。
您可以将标签拆分为一组单词。
然后你可以循环数组并检查文本高度，直到这个词是这样的：
NSString *texttocheck;
float old_height = 0;
int linenumber = 0;
for (x=0; x<[wordarray lenght]; x++) {
texttocheck = [NSString stringWithFormat:@"%@ %@", texttocheck, [wordarray objectAtIndex:x]];
float height = [text sizeWithFont:textLabel.font
constrainedToSize:CGSizeMake(textLabel.bounds.size.width,99999)
lineBreakMode:UILineBreakModeWordWrap].height;
if (old_height < height) {
linenumber++;
}
}
如果高度发生变化，则表示单词前有换行符。
我现在无法检查语法是否正确编写，因此您必须自己检查。
于 2010-12-12T13:27:22.610 回答
2
这是用于获取标签中所有行的 Swift 3 版本。（@fredpi 有类似的答案，但仅适用于第一行）
extension UILabel {
func getArrayOfLinesInLabel() -> [String] {
let text = NSString(string: self.text ?? "-- -- -- --")
let font = self.font ?? // Your default font here
let rect = self.frame
let myFont = CTFontCreateWithName(font.fontName as CFString?, font.pointSize, nil)
let attStr = NSMutableAttributedString(string: text as String)
attStr.addAttribute(String(kCTFontAttributeName), value:myFont, range: NSRange(location: 0, length: attStr.length))
let frameSetter = CTFramesetterCreateWithAttributedString(attStr as CFAttributedString)
let path = CGPath(rect: CGRect(x: 0, y: 0, width: rect.size.width, height: rect.size.height), transform: nil)
let frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, nil)
guard let lines = CTFrameGetLines(frame) as? [CTLine] else {
return []
}
var linesArray = [String]()
for line in lines {
let lineRange = CTLineGetStringRange(line)
let range = NSRange(location: lineRange.location, length: lineRange.length)
let lineString = text.substring(with: range)
linesArray.append(lineString as String)
}
return linesArray
}
}
于 2017-04-07T18:23:18.457 回答
1
斯威夫特 3 - Xcode 8.1
我已将先前答案中的代码放在一起，以创建与 Swift 3、Xcode 8.1 兼容的代码，extension以UILabel返回标签的第一行。
import CoreText
extension UILabel {
/// Returns the String displayed in the first line of the UILabel or "" if text or font is missing
var firstLineString: String {
guard let text = self.text else { return "" }
guard let font = self.font else { return "" }
let rect = self.frame
let attStr = NSMutableAttributedString(string: text)
attStr.addAttribute(String(kCTFontAttributeName), value: CTFontCreateWithName(font.fontName as CFString, font.pointSize, nil), range: NSMakeRange(0, attStr.length))
let frameSetter = CTFramesetterCreateWithAttributedString(attStr as CFAttributedString)
let path = CGMutablePath()
path.addRect(CGRect(x: 0, y: 0, width: rect.size.width + 7, height: 100))
let frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, nil)
guard let line = (CTFrameGetLines(frame) as! [CTLine]).first else { return "" }
let lineString = text[text.startIndex...text.index(text.startIndex, offsetBy: CTLineGetStringRange(line).length-2)]
return lineString
}
}
要使用它，只需像这样firstLineString对您的UILabel实例进行简单调用：
let firstLine = myLabel.firstLineString
于 2016-11-06T12:22:00.010 回答
0
如果您的所有字符都以相同的大小显示，即它们被封闭在一个共同大小的盒子中，您可以利用它。（例如，日语字符似乎就是这种情况。）
否则，您可以查询显示字体中每个字符的大小并计算该行的大小。
那么唯一的担心是你的计算可能与苹果在幕后所做的不一致——在这种情况下，我建议你去覆盖文本框架绘图的麻烦。为此，请在文档中查找 Core Text。
（我可能做错了，但我没有发现文档中给出的 Apple 方法非常准确，所以我自己做了其他事情。）
于 2011-03-28T07:21:58.620 回答
0
接受的答案非常好。
我重构了两个地方：
将10000更改为
CGFloat.greatestFiniteMagnitudeextension将其添加到UILabel我还想提一下，如果您通过设置框架来创建标签，它可以正常工作。如果您使用自动布局，那么不要忘记调用
youLabel.layoutIfNeeded()
以获得正确的帧大小。
这是代码：
extension UILabel {
var stringLines: [String] {
guard let text = text, let font = font else { return [] }
let ctFont = CTFontCreateWithName(font.fontName as CFString, font.pointSize, nil)
let attStr = NSMutableAttributedString(string: text)
attStr.addAttribute(kCTFontAttributeName as NSAttributedString.Key, value: ctFont, range: NSRange(location: 0, length: attStr.length))
let frameSetter = CTFramesetterCreateWithAttributedString(attStr as CFAttributedString)
let path = CGMutablePath()
path.addRect(CGRect(x: 0, y: 0, width: self.frame.size.width, height: CGFloat.greatestFiniteMagnitude), transform: .identity)
let frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, nil)
guard let lines = CTFrameGetLines(frame) as? [Any] else { return [] }
return lines.map { line in
let lineRef = line as! CTLine
let lineRange: CFRange = CTLineGetStringRange(lineRef)
let range = NSRange(location: lineRange.location, length: lineRange.length)
return (text as NSString).substring(with: range)
}
}
}
于 2019-03-14T07:22:42.530 回答
0
对不起，我的声誉太低，无法发表评论。这是Philipp Jahoda对https://stackoverflow.com/a/53783203/2439941的评论。
您的代码片段完美无缺，直到我们在 UILabel 上启用了动态类型。当我们在 iOS 设置应用程序中将文本大小设置为最大值时，它开始丢失返回数组的最后一行中的字符。或者甚至用大量文本完全错过最后一行。
我们设法通过使用不同的方式来解决这个问题frame：
let frameSetter = CTFramesetterCreateWithAttributedString(attStr as CFAttributedString)
let path = UIBezierPath(rect: CGRect(x: 0, y: 0, width: self.frame.width, height: .greatestFiniteMagnitude))
let frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, attStr.length), path.cgPath, nil)
guard let lines = CTFrameGetLines(frame) as? [Any] else { return nil }
现在它适用于任何动态类型大小。
那么完整的功能是：
extension UILabel {
/// creates an array containing one entry for each line of text the label has
var lines: [String]? {
guard let text = text, let font = font else { return nil }
let attStr = NSMutableAttributedString(string: text)
attStr.addAttribute(NSAttributedString.Key.font, value: font, range: NSRange(location: 0, length: attStr.length))
let frameSetter = CTFramesetterCreateWithAttributedString(attStr as CFAttributedString)
let path = UIBezierPath(rect: CGRect(x: 0, y: 0, width: self.frame.width, height: .greatestFiniteMagnitude))
let frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, attStr.length), path.cgPath, nil)
guard let lines = CTFrameGetLines(frame) as? [Any] else { return nil }
var linesArray: [String] = []
for line in lines {
let lineRef = line as! CTLine
let lineRange = CTLineGetStringRange(lineRef)
let range = NSRange(location: lineRange.location, length: lineRange.length)
let lineString = (text as NSString).substring(with: range)
linesArray.append(lineString)
}
return linesArray
}
}
于 2019-05-31T07:07:34.247 回答