NSAttributedString换行

常用属性：

NSFontAttributeName　　　　　　　　　　 文字字体

NSParagraphStyleAttributeName　　　　　段落样式（字符串通过“\n”进行分段，此设置必须在lable.numberOfLines = 0时有效，value通过NSMutableParagraphStyle设置，它有以下属性）

 [段落样式－插曲]
 1 @property(readwrite) CGFloat lineSpacing;　　　　　　　　　　　　　　//行间距 2 @property(readwrite) CGFloat paragraphSpacing;　　　　　　　　　　　//段间距 3 @property(readwrite) NSTextAlignment alignment;　　　　　　　　　　 //对齐方式 4 @property(readwrite) CGFloat firstLineHeadIndent;　　　　　　　　　 //首行缩紧 5 @property(readwrite) CGFloat headIndent;　　　　　　　　　　　　　　 //除首行之外其他行缩进 6 @property(readwrite) CGFloat tailIndent;　　　　　　　　　　　　　　 //每行容纳字符的宽度 7 @property(readwrite) NSLineBreakMode lineBreakMode;　　　　　　　  //换行方式 8 @property(readwrite) CGFloat minimumLineHeight;　　　　　　　　　　 //最小行高 9 @property(readwrite) CGFloat maximumLineHeight;　　　　　　　　　　 //最大行高10 @property(readwrite) NSWritingDirection baseWritingDirection;　　//书写方式（NSWritingDirectionNatural，NSWritingDirectionLeftToRight，NSWritingDirectionRightToLeft）
11 @property(readwrite) CGFloat lineHeightMultiple;
12 @property(readwrite) CGFloat paragraphSpacingBefore;
13 @property(readwrite) float hyphenationFactor;
14 @property(readwrite,copy,NS_NONATOMIC_IOSONLY) NSArray *tabStops NS_AVAILABLE_IOS(7_0);
15 @property(readwrite,NS_NONATOMIC_IOSONLY) CGFloat defaultTabInterval NS_AVAILABLE_IOS(7_0);

 ［段落样式demo］
 1     UILabel * lable = [[UILabel alloc] initWithFrame:CGRectMake(50, 100, self.view.frame.size.width-100, 200)]; 2     lable.backgroundColor = [UIColor lightGrayColor]; 3     lable.numberOfLines = 0; 4     [self.view addSubview:lable]; 5      6     NSString * string = @"Always believe that something wonderful is about \nto happen！"; 7      8     //富文本 9     NSMutableAttributedString * attributedString = [[NSMutableAttributedString alloc] initWithString:string];10     11     //段落样式12     NSMutableParagraphStyle * paragraphStyle = [[NSMutableParagraphStyle alloc] init];13     14 #warning  lable.numberOfLines必须为0，段落样式才生效15     //行间距16     paragraphStyle.lineSpacing = 10.0;17     //段落间距18     paragraphStyle.paragraphSpacing = 20.0;19 20 //    paragraphStyle.baseWritingDirection = NSWritingDirectionLeftToRight;21 //    paragraphStyle.firstLineHeadIndent = 10.0;22 //    paragraphStyle.headIndent = 50.0;23 //    paragraphStyle.tailIndent = 200.0;24     25     [attributedString addAttribute:NSParagraphStyleAttributeName26                              value:paragraphStyle27                              range:NSMakeRange(0, string.length)];28     29     lable.attributedText = attributedString;