iOS之UILabel

1. 换行符\n

UILabel *tips = [[UILabel alloc]initWithFrame:CGRectMake(50, 200, 300 - 20, 60)];

[tips setTextColor:[UIColor grayColor]];

[tips setText:@"支付密码必须为6位数字组合。\n您可依次进入 '功能列表' -> '安全中心' 修改支付密码。\n好的"];

[tips setFont:[UIFont boldSystemFontOfSize:12]];

tips.textAlignment = NSTextAlignmentCenter;

tips.numberOfLines = 0; // 关键一句

[self.view addSubview:tips];

2. 根据字体内容计算frame

UILabel *starLab=[[UILabel alloc]init];

starLab.text =@"打到小日本狗，中华人名共和国万岁！！！";

starLab.textAlignment =NSTextAlignmentLeft;

starLab.numberOfLines = 0;

starLab.font = [UIFont systemFontOfSize:20];

CGSize  titleSize = [starLab.text  boundingRectWithSize: CGSizeMake(100, MAXFLOAT) options: NSStringDrawingUsesLineFragmentOrigin  attributes: @{NSFontAttributeName: [UIFont systemFontOfSize:20]} context: nil].size;

[starLab setFrame:CGRectMake(50, 200, titleSize.width, titleSize.height)];

starLab.textColor =[UIColor blackColor];

[self.view addSubview:starLab];