如何仅为标签创建底部边框？

Question

您好我使用以下代码为我的标签创建了一个底部边框

CALayer *border = [CALayer layer];
    CGFloat borderWidth = 2;
    border.borderColor = [UIColor darkGrayColor].CGColor;
    border.frame = CGRectMake(0, _label.frame.size.height - borderWidth, _label.frame.size.width, _label.frame.size.height);
    border.borderWidth = borderWidth;
    [_label.layer addSublayer:border];
    _label.layer.masksToBounds = YES;

但它的边界是标签的一半。我该如何解决呢？提前谢谢。

Answer 1

你可以这样做：

使用CALayer，您可以在UILabel或任何其他UIControl上创建边框。

1）底部边框

 CALayer *bottomBorder = [CALayer layer];
 bottomBorder.borderColor = [UIColor blackColor].CGColor;
 bottomBorder.borderWidth = 1;
 bottomBorder.frame = CGRectMake(0, CGRectGetHeight(myLabel.frame)-1, CGRectGetWidth(myLabel.frame), 1);
 myLabel.clipsToBounds = YES;
 [myLabel.layer addSublayer:bottomBorder];

2）顶部边框

 CALayer *topBorder = [CALayer layer];
 topBorder.borderColor = [UIColor blackColor].CGColor;
 topBorder.borderWidth = 1;
 topBorder.frame = CGRectMake(0, 0, CGRectGetWidth(myLabel.frame), 1);
 myLabel.clipsToBounds = YES;
 [myLabel.layer addSublayer:topBorder];

3）左边框

 CALayer *leftBorder = [CALayer layer];
 leftBorder.borderColor = [UIColor blackColor].CGColor;
 leftBorder.borderWidth = 1;
 leftBorder.frame = CGRectMake(0, 0, 1, CGRectGetHeight(myLabel.frame));
 myLabel.clipsToBounds = YES;
 [myLabel.layer addSublayer:leftBorder];

4）右边框

 CALayer *rightBorder = [CALayer layer];
 rightBorder.borderColor = [UIColor blackColor].CGColor;
 rightBorder.borderWidth = 1;
 rightBorder.frame = CGRectMake(CGRectGetWidth(myLabel.frame)-1, 0, 1, CGRectGetHeight(myLabel.frame));
 myLabel.clipsToBounds = YES;
 [myLabel.layer addSublayer:rightBorder];

Answer 2

试试吧，

    CALayer* layer = [lbl layer];
    CALayer *bottomBorder = [CALayer layer];
    bottomBorder.borderColor = [UIColor darkGrayColor].CGColor;
    bottomBorder.borderWidth = 1;
    bottomBorder.frame = CGRectMake(-1, layer.frame.size.height-1,layer.frame.size.width, 1);
    [bottomBorder setBorderColor:[UIColor blackColor].CGColor];
    [layer addSublayer:bottomBorder];

Answer 3

您需要根据字符串以及所需的字体计算标签的宽度。 你可以得到像这样的大小

CGSize expectedLabelSize = [yourString sizeWithFont:yourLabel.font 
                    constrainedToSize:maximumLabelSize 
                    lineBreakMode:yourLabel.lineBreakMode]; 

并在为边框设置框架时使用expectedLabelSize。

border.frame = CGRectMake(0, _label.frame.size.height - borderWidth, _expectedLabelSize.width , _label.frame.size.height);

希望它有所帮助。快乐编码!!

Answer 4

请尝试使用以下代码。

UILabel *lbl = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 200, 50)];

[lbl setText：@＆＃34; Testo di prova ...＆＃34;];

[lbl setBackgroundColor：[UIColor clearColor]];

[[self view] addSubview：lbl];

[lbl sizeToFit];

CALayer * layer = [lbl layer];

CALayer * bottomBorder = [CALayer图层];

bottomBorder.borderColor = [UIColor darkGrayColor] .CGColor;

bottomBorder.borderWidth = 1;

bottomBorder.frame = CGRectMake（-1，layer.frame.size.height-1，layer.frame.size.width，1）;

[bottomBorder setBorderColor：[UIColor blackColor] .CGColor];

[layer addSublayer：bottomBorder];