iOS动画两个视图，堆叠在彼此之上

Question

我有动画两个视图的问题！

我有两个按钮可以从底部向上滑动不同的视图。

我想做的事情是：

我像这样动画RegisterView：

class ViewController: UIViewController {

@IBOutlet weak var registerViewHeight: NSLayoutConstraint!
@IBOutlet weak var registerView: UIView!
@IBOutlet weak var registerViewBottomContraint: NSLayoutConstraint!

override func viewDidLoad() {
        super.viewDidLoad()

        self.registerViewBottomContraint.constant = -registerViewHeight.constant

    }

@IBAction func registerButtonPressed(_ sender: AnyObject) {
        self.registerViewBottomContraint.constant = 0
        UIView.animate(withDuration: 0.4, animations: {
            self.view.layoutIfNeeded()
        })

    }

首先：如何正确地将堆叠视图添加到彼此之上？ 第二：有没有办法轻松地从按钮转换到视图？

非常感谢：）

Answer 1

你可以像这样[Objective-C]：

为这些视图设置动画

CGRect viewFrame = self.registerView.frame;
self.registerView.frame = CGRectMake(viewFrame.origin.x, viewFrame.origin.y + viewFrame.size.height, viewFrame.size.width, viewFrame.size.height);
self.registerView.alpha = 0.0;

[UIView animateWithDuration:ANIMATION_DURATION
                      delay:0
                    options:UIViewAnimationOptionCurveEaseOut
                 animations:^{
                     self. registerView.frame = viewFrame;
                     self. registerView.alpha = 1.0;
                 }
                 completion:^(BOOL finished) {

                 }];