Swift 3 - UICollectionView 上的浮动按钮

Question

我通过 this first answer 创建了一个浮动按钮。它有效，但是当 UICollectionView 启动时，浮动按钮仍然是正方形，并在所有数据出现后变成圆形（在 loadAPI 完成后运行）。

这是我的代码：

 override func viewDidLoad() {
    super.viewDidLoad()

    self.roundButton = UIButton(type: .custom)
    self.roundButton.setTitleColor(UIColor.orange, for: .normal)
    self.roundButton.addTarget(self, action: #selector(self.ButtonClick(_:)), for: UIControlEvents.touchUpInside)
    self.view.addSubview(self.roundButton)

    self.loadAPI(Page: 1)
}

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()
    roundButton.layer.cornerRadius = roundButton.layer.frame.size.width/2
    roundButton.backgroundColor = green
    roundButton.clipsToBounds = true
    roundButton.setImage(UIImage(named:"ic_add_white_2x"), for: .normal)
    roundButton.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.activate([
        roundButton.centerXAnchor.constraint(equalTo: self.view.centerXAnchor),
        roundButton.bottomAnchor.constraint(equalTo: self.view.bottomAnchor, constant: -20),
        roundButton.widthAnchor.constraint(equalToConstant: 60),
        roundButton.heightAnchor.constraint(equalToConstant: 60)
    ])
}

@IBAction func ButtonClick(_ sender: UIButton){
 //print("clicked")
}

我需要按钮是一个圆圈，因为 UICollectionView 第一次出现。有人可以帮我吗？谢谢！

Answer 1

// 更新此代码

override func viewDidLoad() {
    super.viewDidLoad()

    self.roundButton = UIButton(type: .custom)
    self.roundButton.setTitleColor(UIColor.orange, for: .normal)
    self.roundButton.layer.cornerRadius = roundButton.layer.frame.size.width/2
    self.roundButton.addTarget(self, action: #selector(self.ButtonClick(_:)), for: UIControlEvents.touchUpInside)
    self.view.addSubview(self.roundButton)

    self.loadAPI(Page: 1)
}

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