在 NavigationItem 中从右侧动画化 UIBarButtonItem

Question

我正在尝试让我的 UIBarButtonItem 从右侧滑入 leftBarButtonItem 位置。

要么滑动到错误的位置然后在设置为 leftBarButtonItem 时跳转，要么根本不可见。这就是我目前正在尝试的..

func createLeftBarButton() {
    // Get the nav bar we'll be working with
    var toolbar = self.navigationItem
    // Initialise our button
    cancelButton = UIButton.buttonWithType(UIButtonType.Custom) as! UIButton
    cancelButton.setTitle("+", forState: UIControlState.Normal)
    cancelButton.setTitleColor(UIColor.blackColor(), forState: UIControlState.Normal)
    cancelButton.addTarget(self, action: "cancel:", forControlEvents: .TouchUpInside)
    cancelButton.titleLabel?.font = UIFont(name: "Courier", size: 34.0)

    // Create a placeholder to get the position and size of the leftBarButtonItem
    placeholderView = UIView(frame: cancelButton.bounds)
    placeholderView.backgroundColor = UIColor.clearColor()
    toolbar.leftBarButtonItem = UIBarButtonItem(customView: placeholderView)

    // Get the frame and position of the placeholderView
    var finalFrame: CGRect = self.view.convertRect(placeholderView.bounds, fromCoordinateSpace: placeholderView)

    // Set the frame for the button to the right of the final location.. this is probably wrong at the moment.
    cancelButton.frame = CGRectMake(-1 * cancelButton.bounds.size.width, finalFrame.origin.y, cancelButton.bounds.size.width, cancelButton.bounds.size.height)

    // Add the button to the view
    self.navigationController?.navigationBar.addSubview(cancelButton)
    // Animate it to the final position
    UIView.animateWithDuration(0.2, animations: {
        self.cancelButton.frame = finalFrame
        }, completion: { _ in
            // Finally set it to the leftBarButtonitem
            toolbar.leftBarButtonItem = UIBarButtonItem(customView: self.cancelButton)
    })


}

Answer 1

您使用占位符视图/子视图的方法有点过于复杂。实际上，您的代码根本不显示任何内容，因为您的 cancelButton 没有框架，然后您的占位符视图继承了该空框架。但即便如此，您仍然会遇到按钮滑动到应有位置下方然后弹回的问题。

认为这可以满足您的需求：

    func createLeftBarButton() {
    // Get the nav bar we'll be working with
    var toolbar = self.navigationItem
    // Initialise our button
    cancelButton = UIButton.buttonWithType(UIButtonType.Custom) as! UIButton
    cancelButton.setTitle("+", forState: UIControlState.Normal)
    cancelButton.setTitleColor(UIColor.blackColor(), forState: UIControlState.Normal)
    cancelButton.addTarget(self, action: "cancel:", forControlEvents: .TouchUpInside)
    cancelButton.titleLabel?.font = UIFont(name: "Courier", size: 34.0)
    cancelButton.frame = CGRectMake(0, 0, 20, 20)
    // Create a placeholder to get the position and size of the leftBarButtonItem
    toolbar.leftBarButtonItem = UIBarButtonItem(customView: cancelButton)

    var delta = self.cancelButton.frame.size.width
    cancelButton.frame = CGRectOffset(cancelButton.frame, -delta, 0.0)

    // Animate it to the final position
    UIView.animateWithDuration(0.2, animations: {
        self.cancelButton.frame = CGRectOffset(self.cancelButton.frame, delta, 0.0)
        }, completion: { _ in
    })
}

在 NavigationItem 中从右侧动画化 UIBarButtonItem

Animate UIBarButtonItem from right in NavigationItem

ios

swift

uibarbuttonitem