中心轴上的旋转按钮

Question

我编写了以下代码来旋转标签栏按钮。但看起来它会旋转左下轴上的按钮，导致按钮略微向右移动。

如何让它绕中心轴旋转？

private func rotateCenterButton(reverse: Bool = false)
{
    if let item = self.tabBarController?.tabBar.items?[2],
       let view = item.value(forKey: "view") as? UIView
    {
        UIView.animate(withDuration: 0.25, animations: {
            view.transform = CGAffineTransform(rotationAngle: reverse ? CGFloat(0) : CGFloat.pi / 4)
        })
    }
}

感谢您的帮助

Answer 1

解决了这样的 mt 问题：

private func rotateCenterButton(reverse: Bool = false)
{
    if let item = self.tabBarController?.tabBar.items?[2],
       let view = item.value(forKey: "view") as? UIView
    {
        let bt = view.subviews.first
        bt!.contentMode = .center
        UIView.animate(withDuration: 0.25, animations:{
            bt!.transform = reverse ? .identity : CGAffineTransform(rotationAngle: .pi/4)
        })
    }
}