控件自适应frame-根据字符串和字体大小

** 一.封装**

    - (CGSize)sizeWithText:(NSString *)text font:(UIFont *)font maxSize:(CGSize)maxSize{
        NSDictionary *attr = @{NSFontAttributeName : font};
        return [text boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:attr context:nil].size;
    }

例子:

     CGSize textSize = [self sizeWithText:message.text font:MNTextFont maxSize:CGSizeMake(200, MAXFLOAT)];
    if (message.type == MNMessageTypeOther) {
        _textF =  CGRectMake(CGRectGetMaxX(_iconF) + 10, CGRectGetMaxY(_timeF)+15, textSize.width+40,   textSize.height+40);
    }else{
        _textF =  CGRectMake(screenW-10-40-10-textSize.width-40, CGRectGetMaxY(_timeF)+15, textSize.width+40, textSize.height+40);
    }

** 二.分类中封装**

    1.创建分类文件 NSString+Extension.h/NSString+Extension.m
    2.在NSString+Extension.h中创建方法
            - (CGSize)sizeWithfont:(UIFont *)font maxSize:(CGSize)maxSize
    3.在NSString+Extension.m中实现该方法
             - (CGSize)sizeWithfont:(UIFont *)font maxSize:(CGSize)maxSize{
                     NSDictionary *attr = @{NSFontAttributeName : font};
                    return [self boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:attr context:nil].size;


            }

    例子:
       CGSize textSize = [message.text sizeWithfont:MNTextFont  maxSize:CGSizeMake(200, MAXFLOAT)];
        if (message.type == MNMessageTypeOther) {
            _textF =  CGRectMake(CGRectGetMaxX(_iconF) + 10, CGRectGetMaxY(_timeF)+15, textSize.width+40, textSize.height+40);
        }else{
             _textF =  CGRectMake(screenW-10-40-10-textSize.width-40, CGRectGetMaxY(_timeF)+15, textSize.width+40, textSize.height+40);

** 三.部分可能会出现自适应高度后文字无法显示完整**

        把label的属性adjustsFontSizeToFitWidth设置成yes就好了