使用 Snapkit 查看动画

Question

我尝试了使用 Snapkit 制作灯光动画的不同教程，但似乎没有任何帮助。我什至尝试过 Spring 框架，但效果不佳。这是我的代码。

private func setupMatchView() {
    view.addSubview(matchOverlayView)
    matchOverlayView.snp.makeConstraints { (make) in
        make.top.equalTo(view.safeAreaLayoutGuide.snp.topMargin)
        make.bottom.equalTo(view.safeAreaLayoutGuide.snp.bottomMargin)
        make.left.equalToSuperview()
        make.right.equalToSuperview()
    }
    matchOverlayView.backgroundColor = UIColor.white.withAlphaComponent(0.5)

    view.addSubview(matchView)
    matchView.snp.makeConstraints { (make) in
        make.left.equalToSuperview().offset(32)
        make.right.equalToSuperview().inset(32)
        make.centerX.equalToSuperview()
        make.centerY.equalToSuperview()
    }
    matchView.backgroundColor = .white
    matchView.layer.cornerRadius = 8
    matchView.dropShadow()

    matchView.addSubview(matchYourImageView)
    matchYourImageView.snp.makeConstraints { (make) in
        make.height.width.equalTo(100)
        make.centerX.equalToSuperview().inset(20)
        make.top.equalToSuperview().offset(40)
    }
    matchYourImageView.backgroundColor = UIColor(red:0.77, green:0.77, blue:0.77, alpha:1.00)
    matchYourImageView.layer.cornerRadius = 50
    matchYourImageView.clipsToBounds = true

    matchView.addSubview(matchHerImageView)
    matchHerImageView.snp.makeConstraints { (make) in
        make.height.width.equalTo(100)
        make.centerX.equalToSuperview().inset(-20)
        make.top.equalTo(matchYourImageView.snp.top)
    }
    matchHerImageView.backgroundColor = UIColor(red:0.69, green:0.69, blue:0.69, alpha:1.00)
    matchHerImageView.layer.cornerRadius = 50
    matchHerImageView.clipsToBounds = true

    matchView.addSubview(matchLabel)
    matchLabel.snp.makeConstraints { (make) in
        make.top.equalTo(matchYourImageView.snp.bottom).offset(64)
        make.centerX.equalToSuperview()
    }
    matchLabel.text = "Match"
    matchLabel.font = UIFont.systemFont(ofSize: 28, weight: .heavy)

    matchView.addSubview(matchCTA)
    matchCTA.snp.makeConstraints { (make) in
        make.top.equalTo(matchLabel.snp.bottom).offset(40)
        make.left.equalToSuperview().offset(32)
        make.right.equalToSuperview().inset(32)
        make.height.equalTo(44)
        make.bottom.equalToSuperview().inset(40)
    }
    matchCTA.setTitle("Go To Chat", for: .normal)


    matchView.addSubview(matchCloseButton)
    matchCloseButton.snp.makeConstraints { (make) in
        make.width.equalTo(32)
        make.height.equalTo(32)
        make.right.equalToSuperview().inset(16)
        make.top.equalToSuperview().inset(16)
    }
    matchCloseButton.setImage(UIImage(named: "Close"), for: .normal)
    matchCloseButton.addTarget(self, action: #selector(self.closeButtonTapped(_:)), for:.touchUpInside)

    matchView.layoutIfNeeded()

    hideMatch()
}

@objc func closeButtonTapped(_ sender:UIButton) {
    hideMatch()
}

private func hideMatch() {
    self.matchOverlayView.alpha = 0
    self.matchView.snp.updateConstraints { (make) in
        make.centerY.equalToSuperview().offset(self.view.frame.height)
    }
    UIView.animate(withDuration: 1) {
        self.matchView.layoutIfNeeded()
    }
}
private func showMatch() {
    self.matchOverlayView.alpha = 1
    self.matchView.snp.updateConstraints { (make) in
        make.centerY.equalToSuperview().offset(0)
    }
    UIView.animate(withDuration: 2) {
        self.matchView.layoutIfNeeded()
    }
}

但这是行不通的。当用户触发showMatch()方法时，该视图仅显示，没有动画。如果有人能提供帮助那就太好了。

Answer 1

你必须调用layoutIfNeeded的matchView超级视图：

private func showMatch() {
    self.matchOverlayView.alpha = 1
    self.matchView.snp.updateConstraints { (make) in
        make.centerY.equalToSuperview().offset(0)
    }
    UIView.animate(withDuration: 2) {
        self.view.layoutIfNeeded()
    }
}

当您调用layoutIfNeeded布局引擎时UIView，布局引擎会使用该视图作为根视图，并开始布局该视图的所有子视图。但只有子视图！

layoutIfNeeded这就是为什么当您调用时布局更改不会产生动画效果matchView。您必须调用的超级视图layoutIfNeeded之一matchView来触发布局更改。