ios - 按下下一个按钮时如何更改上一个按钮的颜色？

Question

我在水平UIScrollView中以编程方式添加了许多按钮。我必须更改用户选择的按钮的颜色。但是，如果用户选择另一个按钮，则先前的按钮颜色必须更改为默认颜色。
我怎样才能做到这一点？请帮我...

func createHorizontalScroll()
{
    let scrollView = UIScrollView(frame: CGRect(x: CGFloat(0), y: CGFloat(410), width: CGFloat(view.frame.size.width), height: CGFloat(40)))

    var buttonX: CGFloat = 0

    for index in 0..<btnNames.count
    {
        //add an element and the previous element together
        let sum = btnNames[index]

        button = UIButton(frame: CGRect(x: CGFloat(buttonX), y: CGFloat(0), width: CGFloat(100), height: CGFloat(40)))

        print("btnNames:\(sum)")

        button.setTitle("\(sum)",for:.normal)
        button.layer.borderWidth = 2.5
        button.layer.borderWidth = 2.5
        button.layer.borderColor = UIColor.white.cgColor
        button.layer.backgroundColor = UIColor.black.cgColor
        button.tag = index
        scrollView.addSubview(button)
        buttonX = button.frame.size.width + buttonX

        button.addTarget(self, action: #selector(changeView), for: .touchUpInside)
    }

    scrollView.contentSize = CGSize(width: CGFloat(buttonX), height: CGFloat(scrollView.frame.size.height))
    scrollView.backgroundColor = UIColor.clear
    view.addSubview(scrollView)
}

func changeView(_ sender: UIButton)
{
   print("I Clicked a button \(Int(sender.tag))")
}

Answer 1

由于您已经在使用标签，所以这不成问题。 changeView函数应如下所示:

func changeView(_ sender: UIButton)
{
    let scrollView = sender.superview as! UIScrollView //This is mildly hacky - store your scroll view in an instance variable
    for view in scrollView.subviews {
        guard let button = view as? UIButton else {
            continue
        }

        button.backgroundColor = sender.tag == button.tag ? UIColor.red : UIColor.black
    }
}