iphone - 为 UILabel 文本添加下划线

Question

这个问题已经有答案了:

Underline text in UIlabel (21 个回答)

已关闭 10 年前。

我有UILabel其字符串是在运行时设置的。 UILabel中的文本是居中对齐的。我想在标签文本下方显示下划线。但该行的 X 位置应与文本开始位置相同(考虑居中对齐)，宽度应等于文本宽度(而不是标签宽度)。对于下划线，我创建了一个 UIView并设置了它的背景颜色。但我无法根据需要修复下划线的长度。

下面是我使用的代码:

 UILabel *blabel = [[UILabel alloc] initWithFrame:CGRectMake(XX, 6, 271, 26)];
    blabel.text = [m_BCListArray objectAtIndex:tagcount];
    blabel.textAlignment = UITextAlignmentCenter;
    blabel.backgroundColor = [UIColor clearColor];
    blabel.textColor = [UIColor whiteColor];
    blabel.font = [UIFont systemFontOfSize:14];
    [scrollDemo addSubview:blabel];

    //underline code
    CGSize expectedLabelSize = [[m_BCListArray objectAtIndex:tagcount] sizeWithFont:blabel.font constrainedToSize:blabel.frame.size lineBreakMode:UILineBreakModeWordWrap];
    CGRect newFrame = blabel.frame;
    newFrame.size.height = expectedLabelSize.height;
    blabel.frame = CGRectMake(blabel.frame.origin.x, blabel.frame.origin.y, 271, expectedLabelSize.height);
    blabel.numberOfLines = 1;
    //[blabel sizeToFit];
    int width=blabel.bounds.size.width;
    int height=blabel.bounds.size.height;

    UIView *viewUnderline=[[UIView alloc] init];
    int len = [[m_BCListArray objectAtIndex:tagcount]length];
    viewUnderline.frame=CGRectMake(XX, 26, len, 1);
    viewUnderline.backgroundColor=[UIColor whiteColor];
    [scrollDemo addSubview:viewUnderline];
    [viewUnderline release];  

如何根据我得到的文本固定线宽？

Answer 1

UILabel *blabel = [[UILabel alloc] initWithFrame:CGRectMake(XX, 6, 271, 26)];
blabel.text = [m_BCListArray objectAtIndex:tagcount];
blabel.textAlignment = UITextAlignmentCenter;
blabel.backgroundColor = [UIColor clearColor];
blabel.textColor = [UIColor whiteColor];
blabel.font = [UIFont systemFontOfSize:14];
[scrollDemo addSubview:blabel];

//underline code
CGSize expectedLabelSize = [[m_BCListArray objectAtIndex:tagcount] sizeWithFont:blabel.font constrainedToSize:blabel.frame.size lineBreakMode:UILineBreakModeWordWrap];

UIView *viewUnderline=[[UIView alloc] init];
viewUnderline.frame=CGRectMake((blabel.frame.size.width - expectedLabelSize.width)/2,    expectedLabelSize.height + (blabel.frame.size.height - expectedLabelSize.height)/2,   expectedLabelSize.width, 1);
viewUnderline.backgroundColor=[UIColor whiteColor];
[scrollDemo addSubview:viewUnderline];
[viewUnderline release];