动态设置label的高度

UILabel *contentLabel=[[UILabel alloc] initWithFrame:_frame];

CGRect frame=contentLabel.frame;

CGSize maximumSize =CGSizeMake(kScreenSize.width-(2*(kScreenSize.width/32.0)),MAXFLOAT);

UIFont *dateFont =[UIFont boldSystemFontOfSize:15.0];

CGSize size = [content boundingRectWithSize:maximumSize options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName : dateFont} context:nil].size;

frame.size.height=size.height;

contentLabel.frame=frame;