根据lable内容设置lable的尺寸

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

lable.text = @"根据lable内容设置尺寸";

lable.frame = [lable textRectForBounds:CGRectMake(15, 20, kDeviceWidth-22, MAXFLOAT) limitedToNumberOfLines:3];