如何计算文字大小行间距的label的高度

         //根据label间距和文字大小计算label的高度

            let string = "我是谁！！！"

            let font =UIFont.systemFontOfSize(12)

            let attStr =NSMutableAttributedString(string: string) 

            let style =NSMutableParagraphStyle()

            style.lineSpacing =12

            attStr.addAttribute(NSParagraphStyleAttributeName, value: style, range:NSMakeRange(0,
string.characters.count))

            let dict = [NSFontAttributeName:font,NSParagraphStyleAttributeName:style]

            let options :NSStringDrawingOptions = .UsesLineFragmentOrigin

            let boundingRect = string.boundingRectWithSize(CGSizeMake(contentView.frame.size.width
- 40, 0), options: options, attributes: dict, context:nil)

--------------------------------------------------------------------------------以下是粘贴大牛的代码

1，单纯调节行间距的方法、能够调整行间距，但是不能调整字间距
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 20, 320, 200)];
    [label setBackgroundColor:[UIColor blackColor]];
    [label setFont:[UIFont systemFontOfSize:16]];
    [label setTextColor:[UIColor whiteColor]];
    [label setNumberOfLines:0];
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setLineSpacing:LINESPACE];//调整行间距
    
    [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [labelText length])];
    label.attributedText = attributedString;
    [self.view addSubview:label];
    [label sizeToFit];

2、附件中有自定义的ZXHMultiLineLabel，以及使用如下：
    ZXHMultiLineLabel *readNewsLable =[[ZXHMultiLineLabel alloc] initWithFrame:CGRectZero];
    readNewsLable.textColor = MAIN_BASE_GRAY_COLOR;
    readNewsLable.lineBreakMode = NSLineBreakByWordWrapping;
    readNewsLable.backgroundColor = [UIColor yellowColor];
    readNewsLable.font = [UIFont fontWithName:contentFontName size:16];
    [readNewsLable setText:labelText];
    
    /*设置label的frame值*/
    [readNewsLable setFrame:CGRectMake(0, 20, 320, [readNewsLable getAttributedStringHeightWidthValue:320])];
    
    NSLog(@"Label高度是多少？ %i", [readNewsLable getAttributedStringHeightWidthValue:320]);
    
    readNewsLable.numberOfLines = 0;
    [self.view addSubview:readNewsLable];

3、根据文字和字体，计算文字的特定高度SpecificWidth内的显示高度
- (CGFloat) initAttributedString:(NSString *)normalString withFont:(NSString *)fontName withSpecificWidth:(CGFloat)inWidth
{
    long stringCharacterSpacing = 1.0f;//字间距
    CGFloat stringLinesSpacing = 4.4f; //行间距

    if(!normalString){
        return 0.0f;
    }

//去掉空行
NSString *myString = [normalString stringByReplacingOccurrencesOfString:@"\r\n" withString:@"\n"];

//创建AttributeString
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc]initWithString:myString];

//设置字体及大小
    UIFont * font = [UIFont fontWithName:contentFontName size:16];
    CTFontRef helveticaBold = CTFontCreateWithName((CFStringRef)font.fontName, font.pointSize, NULL);
    [attributedString addAttribute:(id)kCTFontAttributeName value:(__bridge id)helveticaBold range:NSMakeRange(0,[attributedString
length])];

//设置字间距
//        long number = 1.5f;
//    long number = self.characterSpacing;
    long number = stringCharacterSpacing;

CFNumberRef num = CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt8Type,&number);
    [attributedString addAttribute:(id)kCTKernAttributeName value:(__bridge id)num range:NSMakeRange(0,[attributedString
length])];
    CFRelease(num);
    /*
     if(self.characterSpacing)
     {
     long number = self.characterSpacing;
     CFNumberRef num = CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt8Type,&number);
     [attributedString addAttribute:(id)kCTKernAttributeName value:(id)num range:NSMakeRange(0,[attributedString length])];
     CFRelease(num);
     }
     */

//设置字体颜色
//        [attributedString addAttribute:(id)kCTForegroundColorAttributeName value:(id)(self.textColor.CGColor) range:NSMakeRange(0,[attributedString
length])];
    [attributedString addAttribute:(id)kCTForegroundColorAttributeName value:(id)([UIColor grayColor].CGColor) range:NSMakeRange(0,[attributedString
length])];

//创建文本对齐方式
CTTextAlignment alignment = kCTLeftTextAlignment;
    /*
    if(self.textAlignment == NSTextAlignmentCenter)
    {
        alignment = kCTCenterTextAlignment;
    }
    if(self.textAlignment == NSTextAlignmentRight)
    {
        alignment = kCTRightTextAlignment;
    }
    if(self.textAlignment == NSTextAlignmentLeft)
    {
        alignment = kCTTextAlignmentLeft;
    }
     */
//默认左对齐
    alignment = kCTTextAlignmentLeft;

CTParagraphStyleSetting alignmentStyle;

    alignmentStyle.spec = kCTParagraphStyleSpecifierAlignment;

    alignmentStyle.valueSize = sizeof(alignment);

    alignmentStyle.value = &alignment;

//设置文本行间距

    CGFloat lineSpace = stringLinesSpacing;

CTParagraphStyleSetting lineSpaceStyle;
    lineSpaceStyle.spec = kCTParagraphStyleSpecifierLineSpacingAdjustment;
    lineSpaceStyle.valueSize = sizeof(lineSpace);
    lineSpaceStyle.value =&lineSpace;

//设置文本段间距
    CGFloat paragraphSpacing = 15.0;
    CTParagraphStyleSetting paragraphSpaceStyle;
    paragraphSpaceStyle.spec = kCTParagraphStyleSpecifierParagraphSpacing;
    paragraphSpaceStyle.valueSize = sizeof(CGFloat);
    paragraphSpaceStyle.value = ¶graphSpacing;

//创建设置数组
    CTParagraphStyleSetting settings[ ] ={alignmentStyle,lineSpaceStyle,paragraphSpaceStyle};
    CTParagraphStyleRef style = CTParagraphStyleCreate(settings ,3);

//给文本添加设置
    [attributedString addAttribute:(id)kCTParagraphStyleAttributeName value:(__bridge id)style range:NSMakeRange(0 , [attributedString
length])];
    CFRelease(helveticaBold);

    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef) attributedString);   //string
为要计算高度的
CGSize suggestedSize = CTFramesetterSuggestFrameSizeWithConstraints(framesetter,CFRangeMake(0, 0), NULL,CGSizeMake(inWidth,
CGFLOAT_MAX), NULL);
    CFRelease(framesetter);
    return suggestedSize.height;
}