UILabel 自动适应文字

//显示多行文字

CGSize size = CGSizeMake(Width_mainScreen - 59, MAXFLOAT);

UIFont *fonts = [UIFont systemFontOfSize:15.0];

NSStringDrawingOptions options =  NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading;

NSDictionary * arrtibutes = @{NSFontAttributeName:fonts};

CGRect rect = [label.text boundingRectWithSize:size options:options attributes:arrtibutes context:nil];

CGSize msgSie =  rect.size;

[label setFont:[UIFont boldSystemFontOfSize:15]];

label.frame = CGRectMake(43,70, Width_mainScreen - 59,msgSie.height);

label.lineBreakMode = NSLineBreakByCharWrapping;//实现文字多行显示

label.numberOfLines = 0;