UIButton action not called inside custom view

Question

I want to make a custom view, that will contain the following:

• a green view
• inside the green view an image view
• on top of this another white view
• another image view on top of the white view
• and on top of all an UIButton

This is my code which is inside a custom view:

func setup() {

    // add green view
    let greenView = UIView(frame: CGRectMake(0, 0, frame.size.width, frame.size.height))
    greenView.backgroundColor = UIColor.greenColor()
    greenView.userInteractionEnabled = true
    addSubview(greenView)

    // add first image
    let image1 = UIImageView(frame: CGRectMake(0, 0, frame.size.width, frame.size.height))
    image1.image = UIImage(named: "checked2")
    image1.userInteractionEnabled = true
    greenView.addSubview(image1)

    // add white image
    let whiteView = UIView(frame: CGRectMake(0, 0, frame.size.width, frame.size.height))
    whiteView.backgroundColor = UIColor.yellowColor()
    whiteView.userInteractionEnabled = true
    greenView.addSubview(whiteView)

    // add second image
    let image2 = UIImageView(frame: CGRectMake(0, 0, frame.size.width, frame.size.height))
    image2.image = UIImage(named: "checked")
    image2.userInteractionEnabled = true
    whiteView.addSubview(image2)

    // add button
    let button = UIButton(frame: CGRectMake(0, 0, frame.size.width, frame.size.height))
    button.backgroundColor = UIColor.redColor()
    button.addTarget(self, action: Selector("animation:"), forControlEvents: UIControlEvents.TouchUpInside)
    button.userInteractionEnabled = true
    addSubview(button)



}

func animation(button: UIButton) {
    print("tapped")
}

The button, which is red appears on top, but the action is not called when clicking on it.
I tried to set userInteractionEnabled on all of the elements, but with no effect.

Answer 1

您发布的代码运行正常，问题出在包含所有视图的容器视图中，也许userInteractionEnabled对于容器视图为false。

Answer 2

默认情况下，按钮用户交互是打开的，无需显式设置。