在UILabel中获取第一行的字符串 [英] Get string of first line in a UILabel

问题描述

我在 UILabel 中有一些文字。我想在字符串变量中获取第一个标签的文本。

I have some text in a UILabel. I want to get the text of the first label in a string variable.

例如：

label.text = @"You make an object by creating an instance of a particular class. You do this by allocating the object and initializing it with acceptable default values. When you allocate an object, you set aside enough memory for the object and set all instance variables to zero. Initialization sets an object’s initial state—that is, its instance variables and properties—to reasonable values and then returns the object. The purpose of initialization is to return a usable object. You need to both allocate and initialize an object to be able to use it.";

现在我想得到 UILabel中第一行的文字/ code>。

Now I want to get the text of the first line in the UILabel.

推荐答案

1.添加CoreText.framework。 2.导入#import CoreText / CoreText.h>。
然后使用以下方法 -

1.Add CoreText.framework. 2. Import #import CoreText/CoreText.h>. Then use below method -

-(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;
}

我从下面找到了这个答案url - 如何从UILabel的第n行获取文本？

I found this answer from below url - How to get text from nth line of UILabel?

NSString *firstLineString = [[self getLinesArrayOfStringInLabel:yourLabel] objectAtIndex:0];

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