ios - 为什么当我点击第三个 tabbaritem 时，第三个 tabbaritem 和第四个项目交换位置？

Question

我定制了一个UITabBar。在 UITabBar 的中心添加一个按钮。 tabbar 有 4 个 tabbaritems 和一个按钮。但是当我点击第三个 tabbaritem 时，它的位置变成了第四个项目的位置。第三个 tabbaritem 和第四个 item 交换它们的位置。

我设置断点调试。我发现当我点击第三个 babbaritem tabBar 时调用 layoutSubviews()，但是当我点击其他三个 tabbaritems 时，tabbar 没有调用 layoutSubviews()。我不知道为什么。任何人都可以帮助我吗？

我上传代码。为每个 UITabBarButton 添加标签。然后使用标签乘以宽度。但是它有一个新的问题。第三项成为第一项。

这是固定的自定义 UITarbar。

    class YNNJTTabBar: UITabBar {

    override func awakeFromNib() {
        super.awakeFromNib()

        self.addSubview(askQuestionButton)

        addTagToUITarBarButton()
    }


    func addTagToUITarBarButton() {

        var index = 0
        for view in self.subviews {

            if view is UIControl && !(view is UIButton) {

                view.tag = index
                index += (index == 1) ? 2 : 1

            }
        }
    }

    override func layoutSubviews() {
        super.layoutSubviews()

        let width = self.bounds.width / CGFloat(buttonCount)
        let height = self.bounds.height
        let frame = CGRect(x: 0, y: 0, width: width, height: height)

        //set askQuestionButton's  frame
        let buttonFrame = CGRect(x: 0, y: 0, width: width - 12, height: height - 12)
        askQuestionButton.frame = buttonFrame
        askQuestionButton.center = CGPoint(x: self.bounds.width * 0.5, y: self.bounds.height * 0.5)

        //set 4 item's frame

        for view in self.subviews {

            if view is UIControl && !(view is UIButton) {

                print(view.tag)

                view.frame = CGRectOffset(frame, width * CGFloat(view.tag), 0)

            }


        }

         print(self.subviews as NSArray)
    }


    private let buttonCount = 5

    let askQuestionButton: UIButton = {

        let tempView = UIButton()

        tempView.setBackgroundImage(UIImage(named: "askQuestionbtn"), forState: .Normal)
        tempView.setTitle("问", forState: .Normal)
        tempView.titleLabel?.font = UIFont.systemFontOfSize(22)

        return tempView
    }()  
}

这是应用启动时的打印信息

0
1
3
4
(
    "<_UITabBarBackgroundView: 0x7fe47bc0d580; frame = (0 0; 320 49); autoresize = W; userInteractionEnabled = NO; layer = <CALayer: 0x7fe47bc02740>>",
    "<UITabBarButton: 0x7fe47bccb060; frame = (0 0; 64 49); opaque = NO; layer = <CALayer: 0x7fe47bca51f0>>",
    "<UITabBarButton: 0x7fe47bccc9e0; frame = (64 0; 64 49); opaque = NO; tag = 1; layer = <CALayer: 0x7fe47bcccf80>>",
    "<UITabBarButton: 0x7fe47bccea80; frame = (192 0; 64 49); opaque = NO; tag = 3; layer = <CALayer: 0x7fe47bccf020>>",
    "<UITabBarButton: 0x7fe47bcd0ad0; frame = (256 0; 64 49); opaque = NO; tag = 4; layer = <CALayer: 0x7fe47bcd1050>>",
    "<UIButton: 0x7fe47bcca690; frame = (134 6; 52 37); opaque = NO; layer = <CALayer: 0x7fe47bca3980>>",
    "<UIImageView: 0x7fe47bc22b80; frame = (0 -0.5; 320 0.5); autoresize = W; userInteractionEnabled = NO; layer = <CALayer: 0x7fe47bc07b80>>"
)

当我点击第三个项目时

0
1
4
0
(
    "<_UITabBarBackgroundView: 0x7fe47bc0d580; frame = (0 0; 320 49); autoresize = W; userInteractionEnabled = NO; layer = <CALayer: 0x7fe47bc02740>>",
    "<UITabBarButton: 0x7fe47bccb060; frame = (0 0; 64 49); opaque = NO; layer = <CALayer: 0x7fe47bca51f0>>",
    "<UITabBarButton: 0x7fe47bccc9e0; frame = (64 0; 64 49); opaque = NO; tag = 1; layer = <CALayer: 0x7fe47bcccf80>>",
    "<UITabBarButton: 0x7fe47bcd0ad0; frame = (256 0; 64 49); opaque = NO; tag = 4; layer = <CALayer: 0x7fe47bcd1050>>",
    "<UIButton: 0x7fe47bcca690; frame = (134 6; 52 37); opaque = NO; layer = <CALayer: 0x7fe47bca3980>>",
    "<UIImageView: 0x7fe47bc22b80; frame = (0 -0.5; 320 0.5); autoresize = W; userInteractionEnabled = NO; layer = <CALayer: 0x7fe47bc07b80>>",
    "<UITabBarButton: 0x7fe47bcd0150; frame = (0 0; 64 49); opaque = NO; layer = <CALayer: 0x7fe47bcb8f10>>"
)

Answer 1

如果“self.subviews”返回的项目顺序不正确，为每个选项卡项目设置标签。标签值将为 0(用于搜索)、1(用于联系人)、3 和 4(用于设置)在 for 循环内部更改为:

if view is UIControl && !(view is UIButton) {
    view.frame = CGRectOffset(frame, view.tag * width, 0)
}