iOS富文本NSMutableAttributedString

//富文本的基本数据类型，属性字符串。以此为基础，如果这个设置了相应的属性，则会忽略上面设置的属性，默认为空

NSString *string = label.text;
const CGFloat fontSize = 16.0;
NSMutableAttributedString *attrString = [[NSMutableAttributedString alloc] initWithString:string];
NSUInteger length = [string length];

UIFont *baseFont = [UIFont systemFontOfSize:fontSize];//设置字体
[attrString addAttribute:NSFontAttributeName value:baseFont      
             range:NSMakeRange(0, length)];//设置所有的字体
UIFont *boldFont = [UIFont boldSystemFontOfSize:fontSize];
[attrString addAttribute:NSFontAttributeName value:boldFont range:[string rangeOfString:@"Text"]];//设置Text这四个字母的字体为粗体

UIFont *italicFont = GetVariationOfFontWithTrait(baseFont,
                                                 kCTFontTraitItalic);//设置倾斜，需要导入coreText
[attrString addAttribute:NSFontAttributeName value:italicFont
                   range:[string rangeOfString:@"Label"]];
UIColor *color = [UIColor redColor];// 设置颜色
[attrString addAttribute:NSForegroundColorAttributeName
                   value:color
                   range:[string rangeOfString:@"Content"]];
[attrString addAttribute:NSBackgroundColorAttributeName value:[UIColor blueColor] range:[string rangeOfString:@"ent"]];

//可以对这些属性设置值
//字体名称有以下：
//    label.font = [UIFont fontWithName:@"Arial-BoldItalicMT" size:24];
[attrString addAttribute:NSFontAttributeName value:[UIFont      
       fontWithName:@"Verdana-BoldItalic" size:18] range:[string 
       rangeOfString:@"Label"]];
label.numberOfLines = 2;
NSMutableParagraphStyle * style = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
style.lineSpacing = 10;//增加行高
style.headIndent = 10;//头部缩进，相当于左padding
style.tailIndent = -10;//相当于右padding
style.lineHeightMultiple = 1.5;//行间距是多少倍
style.alignment = NSTextAlignmentLeft;//对齐方式
style.firstLineHeadIndent = 20;//首行头缩进
style.paragraphSpacing = 10;//段落后面的间距
style.paragraphSpacingBefore = 20;//段落之前的间距
[attrString addAttribute:NSParagraphStyleAttributeName value:style range:NSMakeRange(0, length)];
[attrString addAttribute:NSKernAttributeName value:@2 range:NSMakeRange(0, length)];//字符间距 2pt
[attrString addAttribute:NSStrokeColorAttributeName value:[UIColor blueColor] range:[string rangeOfString:@"is"]];//设置文字描边颜色，需要和NSStrokeWidthAttributeName设置描边宽度，这样就能使文字空心
[attrString addAttribute:NSStrokeWidthAttributeName value:@2 range:[string rangeOfString:@"is"]];//空心字，文字边框描述
[attrString addAttribute:NSUnderlineStyleAttributeName value:@(NSUnderlineStyleSingle) range:[string rangeOfString:@"text"]];//下划线
[attrString addAttribute:NSUnderlineStyleAttributeName value:@(NSUnderlineStyleThick) range:[string rangeOfString:@"label"]];//厚的下划线
[attrString addAttribute:NSStrikethroughStyleAttributeName value:@(NSUnderlinePatternSolid | NSUnderlineStyleSingle) range:[string rangeOfString:@"things"]];//删除线
[attrString addAttribute:NSStrikethroughColorAttributeName value:[UIColor blueColor] range:[string rangeOfString:@"things"]];//删除线蓝色