IOS开发中UILabel单行、多行文本计算高度、宽度的技巧

首先来看单行文本的问题：对于单行文本来说，计算CGSize就比较简单了，这里直接上代码了，如下：

NSString *content = @"欢迎来到北京";

CGSize size =[content sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:14]}];

其中14是字体大小，你可以随意指定

最后来看多行文本的显示：

首先UILabel的numberOfLines设置为0，其次通过- (CGRect)boundingRectWithSize:(CGSize)size options:(NSStringDrawingOptions)options attributes:(NSDictionary *)attributes context:(NSStringDrawingContext *)context方法来计算CGSize，具体代码如下：

    UILabel *titleLabel = [UILabel new];     titleLabel.font = [UIFont systemFontOfSize:14];     NSString *titleContent = @"亲，欢迎您通过以下方式与我们的营销顾问取得联系，交流您再营销推广工作中遇到的问题，营销顾问将免费为您提供咨询服务。";     titleLabel.text = titleContent;     titleLabel.numberOfLines = 0;//多行显示，计算高度     titleLabel.textColor = [UIColor lightGrayColor];     CGSize titleSize = [titleContent boundingRectWithSize:CGSizeMake(kScreen_Width, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:14]} context:nil].size;     titleLabel.size = titleSize;     titleLabel.x = 0;     titleLabel.y = 0;          [self.view addSubview:titleLabel];

#define HEIGHT [ [ UIScreen mainScreen ] bounds ].size.height

//给UILabel设置行间距和字间距

-(void)setLabelSpace:(UILabel*)label withValue:(NSString*)str withFont:(UIFont*)font {

    NSMutableParagraphStyle *paraStyle = [[NSMutableParagraphStyle alloc] init];

    paraStyle.lineBreakMode = NSLineBreakByCharWrapping;

    paraStyle.alignment = NSTextAlignmentLeft;

    paraStyle.lineSpacing = UILABEL_LINE_SPACE; //设置行间距

    paraStyle.hyphenationFactor = 1.0;

    paraStyle.firstLineHeadIndent = 0.0;

    paraStyle.paragraphSpacingBefore = 0.0;

    paraStyle.headIndent = 0;

    paraStyle.tailIndent = 0;

    //设置字间距 NSKernAttributeName:@1.5f

    NSDictionary *dic = @{NSFontAttributeName:font, NSParagraphStyleAttributeName:paraStyle, NSKernAttributeName:@1.5f };

    

    NSAttributedString *attributeStr = [[NSAttributedString alloc] initWithString:str attributes:dic];

    label.attributedText = attributeStr;

}

//计算UILabel的高度(带有行间距的情况)

-(CGFloat)getSpaceLabelHeight:(NSString*)str withFont:(UIFont*)font withWidth:(CGFloat)width {

    NSMutableParagraphStyle *paraStyle = [[NSMutableParagraphStyle alloc] init];

    paraStyle.lineBreakMode = NSLineBreakByCharWrapping;

    paraStyle.alignment = NSTextAlignmentLeft;

    paraStyle.lineSpacing = UILABEL_LINE_SPACE;

    paraStyle.hyphenationFactor = 1.0;

    paraStyle.firstLineHeadIndent = 0.0;

    paraStyle.paragraphSpacingBefore = 0.0;

    paraStyle.headIndent = 0;

    paraStyle.tailIndent = 0;

    NSDictionary *dic = @{NSFontAttributeName:font, NSParagraphStyleAttributeName:paraStyle, NSKernAttributeName:@1.5f };

    

    CGSize size = [str boundingRectWithSize:CGSizeMake(width, HEIGHT) options:NSStringDrawingUsesLineFragmentOrigin attributes:dic context:nil].size;

    return size.height;

}