Question

我正在尝试为选定的分段控件添加边框。目前，我有代码将3px的边界设置为整个分段控件的底部：

CALayer *bottomBorder = [CALayer layer];
bottomBorder.borderColor = [UIColor redColor].CGColor;
bottomBorder.borderWidth = 3;
bottomBorder.frame = CGRectMake(0, self.segmentedControl.frame.size.height - bottomBorder.borderWidth, self.segmentedControl.frame.size.width, bottomBorder.borderWidth);
[self.segmentedControl.layer addSublayer:bottomBorder];

但是，我想将此边框仅添加到选定的分段控件。我该怎么做？

Answer 1

您可以使用以下代码动态添加选择：

// Removing previous selection
[bottomBorder removeFromSuperlayer];

// Creating new layer for selection
bottomBorder             = [CALayer layer];
bottomBorder.borderColor = [UIColor redColor].CGColor;
bottomBorder.borderWidth = 3;

// Calculating frame
CGFloat width            = self.segmentedControl.frame.size.width/3;
CGFloat x                = self.segmentedControl.selectedSegmentIndex * width;
CGFloat y                = self.segmentedControl.frame.size.height - bottomBorder.borderWidth;
bottomBorder.frame       = CGRectMake(x, y,width, bottomBorder.borderWidth);

// Adding selection to segment
[self.segmentedControl.layer addSublayer:bottomBorder];

选择新选项时，您需要删除先前的选择，为此，将bottomBorder图层作为成员变量。

Answer 2

我将Objective-C解决方案转换为swift3它对我有用，我的Segment控制器宽度等于View width

@IBAction func SegmentAction(_ sender: UISegmentedControl) {

    self.segmentBottomBorder?.removeFromSuperlayer()
    self.segmentBottomBorder = CALayer()
    self.segmentBottomBorder?.borderColor = UIColor.red.cgColor
    self.segmentBottomBorder?.borderWidth = 3
    let x = CGFloat(sender.selectedSegmentIndex) * width
    let y = sender.frame.size.height - (self.segmentBottomBorder?.borderWidth)!
    let width: CGFloat = sender.frame.size.width/3
    self.segmentBottomBorder?.frame = CGRect(x: x, y: y, width: width, height: (self.segmentBottomBorder?.borderWidth)!)
    sender.layer.addSublayer(self.segmentBottomBorder!)
}

Answer 3

这可能不是正确的方法，但你可以试一试。

在加载段控件时，请在viewdidload中尝试此操作，以便根据selectedsegment按钮添加图层

if (self.segmentedControl.selectedSegmentIndex==0) {

    CALayer *bottomBorder = [CALayer layer];
    bottomBorder.borderColor = [UIColor redColor].CGColor;
    bottomBorder.borderWidth = 3;
    bottomBorder.frame = CGRectMake(0, self.segmentedControl.frame.size.height - bottomBorder.borderWidth, self.segmentedControl.frame.size.width/2, bottomBorder.borderWidth);

    [self.segmentedControl.layer addSublayer:bottomBorder];


}else if (self.segmentedControl.selectedSegmentIndex==1){

    //change the border layer frame


} else if (self.segmentedControl.selectedSegmentIndex==2){
    //change the border layer frame
  }

再次在segmentcontrol操作方法中，您可以更改这些更改

Answer 4

//Connect action to segmented control.

- (IBAction)segmentedControlAction:(id)sender {

if(segmentedControl.selectedSegmentIndex == 0)
{
    NSLog(@"First Segment (Feed) Selected");

    //Remove SuperLayer when segment is selected
    [_bottomBorder removeFromSuperlayer];

    // Creating new layer for selection
    _bottomBorder  = [CALayer layer];
    _bottomBorder.borderColor = [UIColor redColor].CGColor;
    _bottomBorder.borderWidth = 3;

    // Calculating frame
    CGFloat width = self.segmentedControl.frame.size.width/3;
    CGFloat x = self.segmentedControl.selectedSegmentIndex * width;
    CGFloat y = self.segmentedControl.frame.size.height - _bottomBorder.borderWidth;
    _bottomBorder.frame = CGRectMake(x, y,width, _bottomBorder.borderWidth);

    // Adding selection to segment
    [self.segmentedControl.layer addSublayer:_bottomBorder];

}
else if(segmentedControl.selectedSegmentIndex == 1)
    {
        NSLog(@"Second Segment (Stations) Selected");

        //Remove SuperLayer when segment is selected
        [_bottomBorder removeFromSuperlayer];

        // Creating new layer for selection
        _bottomBorder  = [CALayer layer];
        _bottomBorder.borderColor = [UIColor redColor].CGColor;
        _bottomBorder.borderWidth = 3;

        // Calculating frame
        CGFloat width = self.segmentedControl.frame.size.width/3;
        CGFloat x = self.segmentedControl.frame.size.width/3;
        CGFloat y = self.segmentedControl.frame.size.height - _bottomBorder.borderWidth;
        _bottomBorder.frame = CGRectMake(x, y,width, _bottomBorder.borderWidth);

        // Adding selection to segment
        [self.segmentedControl.layer addSublayer:_bottomBorder];


    }

else if(segmentedControl.selectedSegmentIndex == 2)
    {
       NSLog(@"Third Segment (Events) Selected");

        //Remove SuperLayer when segment is selected
        [_bottomBorder removeFromSuperlayer];

        // Creating new layer for selection
        _bottomBorder  = [CALayer layer];
        _bottomBorder.borderColor = [UIColor redColor].CGColor;
        _bottomBorder.borderWidth = 3;

        // Calculating frame
        CGFloat width = self.segmentedControl.frame.size.width/3;
        CGFloat x = self.view.bounds.size.width - self.segmentedControl.frame.size.width/3;
        CGFloat y = self.segmentedControl.frame.size.height - _bottomBorder.borderWidth;
        _bottomBorder.frame = CGRectMake(x, y,width, _bottomBorder.borderWidth);

        // Adding selection to segment
        [self.segmentedControl.layer addSublayer:_bottomBorder];

    }
}

将Border添加到SELECTED分段控件的底部

4 个答案: