Question

是否有一种简单的方法可以获取（或简单显示）UILabel中给定行的文本？

我的UILabel正确显示我的文字并将其整理出来，但偶尔我需要能够显示某些行，但显然我需要知道UILabel如何定位所有这些。

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。

或者我可以滚动UILabel，如果UILabel的框架有某种偏移并隐藏了我不想看到的其他内容。

我无法发现任何可以轻松完成此操作的内容。有人有什么好主意吗？

由于

iphaaw

Answer 1

我有更好的方法找到它。

您可以在CoreText.framework的帮助下获得此作品。

1.添加CoreText.framework。
2.导入 #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。

SWIFT 4版本

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: CTFont = CTFontCreateWithName(font.fontName as CFString, font.pointSize, 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
 }

使用：

let lines: [String] = getLinesArrayOfString(in: label)

Answer 2

Swift 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（测试过，并从Swift 1回答中重新编辑）

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
}

Answer 3

以正确的版本回答!!!!

-(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;
}

Answer 4

我不认为有这样的本地方式（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系列单词然后你可以循环数组并检查文本高度，直到这个词如下：

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，则表示在单词前有换行符我现在无法检查语法是否正确写入，因此您必须自己检查。

Answer 5

这是获取标签中所有行的Swift 3版本。（@fredpi有类似的答案，但它只适用于第一行）

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
   }
}

Answer 6

Swift 3 - Xcode 8.1

我已将先前答案中的代码放在一起，以创建一个Swift 3，兼容Xcode 8.1 extension到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，请在firstLineString个实例上简单地调用UILabel，如下所示：

let firstLine = myLabel.firstLineString

Answer 7

关于iOS 11+的非常重要的更改

从iOS 11开始，Apple故意更改了UILabel的自动换行功能的行为，这会检测多行{{ 1}}。通过设计，String的自动换行现在可以避免孤立的文本（在新行中包含单个单词），如下所述：word wrapping in iOS 11

因此，如果避免孤立文本的新换行在特定行中生效，则UILabel返回标签中所有行的UILabel数组的方式将不再正确工作。相反，它导致CTFrameGetLines(frame)的某些部分通过新的自动换行设计将属于下一行，而不是最终成为焦点所在的行。

可以在我更改后的@TheTiger's answer版本中找到经过测试的修复程序，该版本利用CTLine计算String的实际内容大小，然后再使用该大小创建用 Swift 4 ：

编写的rect /路径

UILabel

此扩展名sizeThatFits(size:)以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 } }数组的形式返回标签的内容，每行有一个与用户所看到的完全相同的条目。

Answer 8

如果所有字符都以相同的大小显示，即它们被包含在一个常见大小的框中，您可以利用它。（例如，日语字符就是这种情况。）

否则，您可以查询显示字体中每个字符的大小，并计算该行必须是什么。

唯一的担心是你的计算可能不同意Apple在幕后所做的事情 - 在这种情况下，我建议你去覆盖文本框架绘图的麻烦。在文档中查找核心文本。

（我可能这样做错了，但我没有发现Apple的方法在文档中给出的非常准确，所以我自己做了别的事。）

Answer 9

接受的答案非常好。

我重构了两个地方：

将 10000 更改为CGFloat.greatestFiniteMagnitude
已将其添加到extension的{{1}}
我也想提及一下，如果您通过设置框架来创建标签，则效果很好。如果您使用自动版式，请不要忘记拨打电话

UILabel

获取正确的帧大小。

代码如下：

youLabel.layoutIfNeeded()

Answer 10

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。

您的代码段完美运行，直到我们在UILabel上启用了动态类型。当我们在iOS设置应用中将文本大小设置为最大值时，它开始丢失返回数组最后一行中的字符。甚至完全缺少大量文本的最后一行。

我们设法通过另一种方式获得frame来解决此问题：

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，它可以在任何动态类型大小下正常工作。

然后是完整功能：

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
    }
}

如何从UILabel的第n行获取text / String？

10 个答案: