Question

我想在菜单上的所选按钮下添加一个白色水平条。就像YouTube应用。 This is my menu

我搜索了信息，但我找不到任何相关信息。这是我的代码。感谢

import UIKit

class TabViewController: UIViewController {


    @IBOutlet var contentView: UIView!
    @IBOutlet var buttons: [UIButton]!

    var rifleViewController: UIViewController!
    var pistolViewController: UIViewController!
    var shotgunViewController: UIViewController!
    var smgsViewController: UIViewController!
    var sniperViewController: UIViewController!

    var viewControllers: [UIViewController]!
    var selectedIndex: Int = 0

    override func viewDidLoad() {
        super.viewDidLoad()

        let storyboard = UIStoryboard(name: "Main", bundle: nil)

        rifleViewController = storyboard.instantiateViewController(withIdentifier: "rifles")
        sniperViewController = storyboard.instantiateViewController(withIdentifier: "snipers")
        smgsViewController = storyboard.instantiateViewController(withIdentifier: "smgss")
        shotgunViewController = storyboard.instantiateViewController(withIdentifier: "shotguns")
        pistolViewController = storyboard.instantiateViewController(withIdentifier: "pistols")
        viewControllers = [rifleViewController,
                           pistolViewController,
                           shotgunViewController,
                           smgsViewController,
                           sniperViewController]

        buttons[selectedIndex].isSelected = true
        didPressTab(buttons[selectedIndex])


    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    @IBAction func didPressTab(_ sender: UIButton) {

        let previousIndex = selectedIndex

        selectedIndex = sender.tag

        buttons[previousIndex].isSelected = false
        let previousVC = viewControllers[previousIndex]

        previousVC.willMove(toParentViewController: nil)
        previousVC.view.removeFromSuperview()
        previousVC.removeFromParentViewController()

        sender.isSelected = true

        let vc = viewControllers[selectedIndex]

        addChildViewController(vc)

        vc.view.frame = contentView.bounds
        contentView.addSubview(vc.view)
        vc.didMove(toParentViewController: self)   

    }

}

Answer 1

您可以借助简单的动画实现这一目标。在我的示例 - 应用程序中，我在故事板的屏幕顶部添加了一个视图，并在其顶部放置了四个按钮。然后我将按钮连接到名为“buttonTapped”的功能（重要的是：您需要在此处包含发件人）。代码很简单：

class ViewController: UIViewController {

@IBOutlet weak var backgroundView: UIView!
var movingView = UIView()

override func viewDidLoad() {
    super.viewDidLoad()

    let screenWidth = UIScreen.main.bounds.width

    movingView = UIView(frame: CGRect(x: 0, y: 55, width: screenWidth / 4, height: 5))
    movingView.backgroundColor = UIColor.white   //if backgroundView's color is black
    backgroundView.addSubview(movingView)
}


@IBAction func buttonTapped(_ sender: UIButton)
{
    let newx = sender.frame.origin.x

    UIView.animate(withDuration: 1) {
        self.movingView.frame.origin.x = newx
    }
}
}

Swift - 所选按钮下的水平栏

1 个答案: