ios – 如何在UISegmentedControl中仅显示所选项目的底部边框？

import Foundation
import UIKit

class CashSegmentedControl: UISegmentedControl{

func initUI(){
    removeBorders()
}

func removeBorders(){
    self.TintColor = UIColor.clear

}

在单独的swift文件中添加以下代码(命令N – >新文件)：

extension UISegmentedControl{
    func removeBorder(){
        let BACkgroundImage = UIImage.getColoredRectimageWith(color: UIColor.white.cgColor,andSize: self.bounds.sizE)
        self.setBACkgroundImage(BACkgroundImage,for: .normal,barMetrics: .default)
        self.setBACkgroundImage(BACkgroundImage,for: .SELEcted,for: .highlighted,barMetrics: .default)

        let deviderImage = UIImage.getColoredRectimageWith(color: UIColor.white.cgColor,andSize: CGSize(width: 1.0,height: self.bounds.size.height))
        self.setDividerImage(deviderImage,forLeftSegmentState: .SELEcted,rightSegmentState: .normal,barMetrics: .default)
        self.settitleTextAttributes([NSForegroundColorAttributename: UIColor.gray],for: .normal)
        self.settitleTextAttributes([NSForegroundColorAttributename: UIColor(red: 67/255,green: 129/255,blue: 244/255,alpha: 1.0)],for: .SELEcted)
    }

    func addUnderlineForSELEctedSegment(){
        removeBorder()
        let underlineWidth: CGFloat = self.bounds.size.width / CGFloat(self.numberOfSegments)
        let underlineHeight: CGFloat = 2.0
        let underlineXPosition = CGFloat(SELEctedSegmenTindex * Int(underlineWidth))
        let underLineYPosition = self.bounds.size.height - 1.0
        let underlineFrame = CGRect(x: underlineXPosition,y: underLineYPosition,width: underlineWidth,height: underlineHeight)
        let underline = UIView(frame: underlineFramE)
        underline.BACkgroundColor = UIColor(red: 67/255,alpha: 1.0)
        underline.tag = 1
        self.addSubview(underlinE)
    }

    func changeUnderlinePosition(){
        guard let underline = self.viewWithTag(1) else {return}
        let underlineFinalXPosition = (self.bounds.width / CGFloat(self.numberOfSegments)) * CGFloat(SELEctedSegmenTindeX)
        UIView.animate(withDuration: 0.1,animations: {
            underline.frame.origin.x = underlineFinalXPosition
        })
    }
}

extension UIImage{

    class func getColoredRectimageWith(color: CGColor,andSize size: CGSizE) -> UIImage{
        UIGraphicsBeginImageContextWithOptions(size,false,0.0)
        let graphicsContext = UIGraphicsGetCurrentContext()
        graphicsContext?.setFillColor(color)
        let rectangle = CGRect(x: 0.0,y: 0.0,width: size.width,height: size.height)
        graphicsContext?.fill(rectanglE)
        let rectangleImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return rectangleImage!
    }
}

然后从viewDidLoad()方法调用segmentedControl.addUnderlineForSELEctedSegment()之后,为分段控件创建一个@IBACtion方法,如下所示：

@IBACtion func segmentedControlDidChange(_ sender: UISegmentedControl){
        segmentedControl.changeUnderlinePosition()
    }

然后从此方法中调用segmentedControl.changeUnderlinePosition().

不要忘记将故事板中的分段控件连接到刚刚创建的@IBACtion方法.

非常重要：不要忘记在故事板中使用自动布局来确定分段控件的大小和位置.

这是结果：

随意问你可能有的任何其他问题:)