- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view,typically from a nib.
self.label = [[UILabel alloc] initWithFrame:CGRectMake(90,90,200,90)];
[self.view addSubview:self.label];
self.label.font = [UIFont systemFontOfSize:13];
self.label.numberOfLines = 0;
self.label.text = @"今天是个好日子啊今天是个好日子今天是个好日子啊今天是个好日子今天是个好日子啊今天是个好日子今天是个好日子啊今天是个好日子今天是个好日子啊今天是个好日子今天是个好日子啊今天是个好日子";

//------- 设置行距 -------//
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc]initWithString:self.label.text];;
NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc]init];
[paragraphStyle setLineSpacing:15];
[attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0,self.label.text.length)];
self.label.attributedText = attributedString;
}