iOS 动态设置Label的高度，行与行其间有间隔

**重点内容**CGFloat lineSpace=15;

self.labelTwo = [[UILabel alloc]init];
self.labelTwo.text = @"请输入您对老师或课程的疑问，并在下方上传您的凭证";
self.labelTwo.textColor = [UIColor lightGrayColor];
self.labelTwo.numberOfLines = 0;
self.labelTwo.font = [UIFont fontWithName:@"Hiragino Sans GB" size:14];

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
paragraphStyle.lineSpacing = lineSpace;
paragraphStyle.alignment = NSTextAlignmentLeft;
paragraphStyle.lineBreakMode = NSLineBreakByWordWrapping;
NSDictionary *attributes = @{NSParagraphStyleAttributeName: paragraphStyle,NSFontAttributeName:self.labelTwo.font};

CGSize labelSize=[self.labelTwo.text boundingRectWithSize:CGSizeMake(textView.frame.size.width,0) options:\
                  NSStringDrawingTruncatesLastVisibleLine |
                  NSStringDrawingUsesLineFragmentOrigin |
                  NSStringDrawingUsesFontLeading attributes:attributes context:nil].size;



self.labelTwo.frame=CGRectMake(0,0,labelSize.width,labelSize.height);