将顶部边框添加到选定的TabBar

问题描述

如何在选定的TabBar的顶部添加边框。 下面是我曾经在底部添加但我想要的方法

extension UIImage {
    func createSelectionIndicator(color: UIColor,size: CGSize,linewidth: CGFloat) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(size,false,0)
        color.setFill()
        UIRectFill(CGRect(x: 0,y: size.height - linewidth,width: size.width,height: linewidth))
        let image = UIGraphicsGetimageFromCurrentimageContext()
        UIGraphicsEndImageContext()
        return image!
    }
}

tabBar.selectionIndicatorImage = UIImage().createSelectionIndicator(color: BLUE,size: CGSize(width: tabBar.frame.width/CGFloat(tabBar.items!.count),height:  tabBar.frame.height),linewidth: 2.0)

解决方法

您可以使用该功能在任意一侧创建边框-

enum Side: String {
    case top,left,right,bottom
}

extension UIImage {
    func createSelectionIndicator(color: UIColor,size: CGSize,lineThickness: CGFloat,side: Side) -> UIImage {
        var xPosition = 0.0
        var yPosition = 0.0
        var imgWidth = 2.0
        var imgHeight = 2.0
        switch side {
            case .top:
                xPosition = 0.0
                yPosition = 0.0
                imgWidth = size.width
                imgHeight = lineThickness
            case .bottom:
                xPosition = 0.0
                yPosition = size.height - lineThickness
                imgWidth = size.width
                imgHeight = lineThickness
            case .left:
                xPosition = 0.0
                yPosition = 0.0
                imgWidth = lineThickness
                imgHeight = size.height
            case .right:
                xPosition = size.width - lineThickness
                yPosition = 0.0
                imgWidth = lineThickness
                imgHeight = size.height
        }
        UIGraphicsBeginImageContextWithOptions(size,false,0)
        color.setFill()
        UIRectFill(CGRect(x: xPosition,y: yPosition,width: imgWidth,height: imgHeight))
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image!
    }
}

tabBar.selectionIndicatorImage = UIImage().createSelectionIndicator(color: BLUE,size: CGSize(width: tabBar.frame.width/CGFloat(tabBar.items!.count),height:  tabBar.frame.height),lineThickness: 2.0,side: .top)

让我知道这是否有用，或者您需要其他帮助。 快乐编码：）

,

导入UIKit

class MyViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        tabBarController?.tabBar.addBorder(.top,color: .red,thickness: 2.0)
    }
   
}
extension UITabBar {
    func addBorder(_ edge: UIRectEdge,color: UIColor,thickness: CGFloat) {
        let subview = UIView()
        subview.translatesAutoresizingMaskIntoConstraints = false
        subview.backgroundColor = color
        self.addSubview(subview)
        switch edge {
        case .top,.bottom:
            subview.leftAnchor.constraint(equalTo: self.leftAnchor,constant: 0).isActive = true
            subview.rightAnchor.constraint(equalTo: self.rightAnchor,constant: 0).isActive = true
            subview.heightAnchor.constraint(equalToConstant: thickness).isActive = true
            if edge == .top {
                subview.topAnchor.constraint(equalTo: self.topAnchor,constant: 0).isActive = true
            } else {
                subview.bottomAnchor.constraint(equalTo: self.bottomAnchor,constant: 0).isActive = true
            }
        case .left,.right:
            subview.topAnchor.constraint(equalTo: self.topAnchor,constant: 0).isActive = true
            subview.bottomAnchor.constraint(equalTo: self.bottomAnchor,constant: 0).isActive = true
            subview.widthAnchor.constraint(equalToConstant: thickness).isActive = true
            if edge == .left {
                subview.leftAnchor.constraint(equalTo: self.leftAnchor,constant: 0).isActive = true
            } else {
                subview.rightAnchor.constraint(equalTo: self.rightAnchor,constant: 0).isActive = true
            }
        default:
            break
        }
    }
}

tabBarController?.tabBar.addBorder(.top,color: .orange,thickness: 5.0)