Question

当我旋转设备时，无论旋转如何，屏幕中间的红色方块都会移动到屏幕中央。但是，在旋转设备时，the square does not immediately reposition itself, instead the previous location of the square can be seen until the rotation animation is fully complete.是否可以在播放动画时立即重新定位方形，以便在旋转动画期间看不到旧位置？

import UIKit

class ViewController: UIViewController {
    var square = UIView()

    override func viewDidLoad() {
        super.viewDidLoad()

        square.isHidden = true

        square = UIView(frame: CGRect(x: self.view.frame.width / 2 - 50, y: self.view.frame.height / 2 - 50, width: 100, height: 100))
        square.backgroundColor = UIColor.red
        self.view.addSubview(square)
        square.isHidden = false
    }

    override func didRotate(from fromInterfaceOrientation: UIInterfaceOrientation) {
        square.isHidden = true
        square = UIView(frame: CGRect(x: self.view.frame.width / 2 - 50, y: self.view.frame.height / 2 - 50, width: 100, height: 100))
        square.backgroundColor = UIColor.red
        self.view.addSubview(square)
        square.isHidden = false
    }
}

Answer 1

两件事：

didRotate在iOS 8中被弃用了。它已被viewWillTransition(to:with:)取代。
不要创建新的方块。只需更新原始方块的框架即可。

下面的代码会创建一个方格并设置autoresizingMask以使其居中。无需做任何其他事情。当然，您也可以设置约束而不是autoresizingMask。

import UIKit

class ViewController: UIViewController {
    var square: UIView!

    override func viewDidLoad() {
        super.viewDidLoad()

        square = UIView(frame: CGRect(x: self.view.frame.width / 2 - 50, y: self.view.frame.height / 2 - 50, width: 100, height: 100))
        square.backgroundColor = UIColor.red
        square.autoresizingMask = [ .flexibleLeftMargin, .flexibleRightMargin, .flexibleTopMargin, .flexibleBottonMargin ]
        self.view.addSubview(square)
    }
}

可以让屏幕元素立即旋转

1 个答案: