根据字符内容计算宽高度

根据内容计算宽度

- (CGFloat)calculateRowWidth:(NSString *)string {  
    NSDictionary *dic = @{NSFontAttributeName:[UIFont systemFontOfSize:17]};  //指定字号  
    CGRect rect = [string boundingRectWithSize:CGSizeMake(0, 30)/*计算宽度时要确定高度*/ options:NSStringDrawingUsesLineFragmentOrigin |  
                   NSStringDrawingUsesFontLeading attributes:dic context:nil];  
    return rect.size.width;  
}

根据内容计算高度

- (CGFloat)calculateRowHeight:(NSString *)string fontSize:(NSInteger)fontSize{  
    NSDictionary *dic = @{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]};//指定字号  
    CGRect rect = [string boundingRectWithSize:CGSizeMake(self.view.width - 30, 0)/*计算高度要先指定宽度*/ options:NSStringDrawingUsesLineFragmentOrigin |  
                   NSStringDrawingUsesFontLeading attributes:dic context:nil];  
    return rect.size.height;  
}

 二、如果两行或者多行 字符串的时候 设置行间隔  在动态计算高度 如下两段代码

- (CGFloat)calculateRowHeight:(NSString *)string fontSize:(NSInteger)fontSize strWithWidthX:(CGFloat)widthX
{
    NSDictionary *dic = [self setParameterWithfloat:5 fontSize:fontSize];
    // 计算高度要先指定宽度
    CGRect rect = [string boundingRectWithSize:CGSizeMake(kUIScreenWidth - widthX, 0) options:NSStringDrawingUsesLineFragmentOrigin |
                   NSStringDrawingUsesFontLeading attributes:dic context:nil];
    return rect.size.height;
}

//设置行间距
- (NSDictionary *)setParameterWithfloat:(CGFloat )heightForLineSpacing fontSize:(NSInteger)fontSize
{
    NSMutableParagraphStyle *paraStyle = [[NSMutableParagraphStyle alloc] init];
    paraStyle.lineBreakMode = NSLineBreakByCharWrapping;
    paraStyle.alignment = NSTextAlignmentLeft;
    // 设置行间距
    paraStyle.lineSpacing = heightForLineSpacing;
    // 指定字号
    NSDictionary *dic = @{NSFontAttributeName:[UIFont systemFontOfSize:fontSize], NSParagraphStyleAttributeName:paraStyle};
    return dic;
}