swift - UISearchBar 显示取消按钮动画完成

Question

我需要知道 UISearchBar 的取消按钮在调用后何时完成他的动画

searchBar.setShowsCancelButton(false, animated: true)

我试过了

UIView.animateWithDuration(3, animations: {
    self.searchBarView.searchBar.showsCancelButton = false
         }, completion: {finished in
         print(finished)
})

但是会立即触发完成 block ，任何解决方案都将不胜感激

Answer 1

您可以使用 layoutIfNeeded() 来更新 UIView.animateWithDuration(...) 中的 View

试试这段代码:

import UIKit

class ViewController: UIViewController {

@IBOutlet var searchBar: UISearchBar!

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

@IBAction func touchUpInside(sender: UIButton) {
    searchBar.showsCancelButton = !searchBar.showsCancelButton
    UIView.animateWithDuration(3, animations: {
        self.searchBar.layoutIfNeeded()
        }, completion: {finished in
            print("Animation finished")
    })
}
}

和 Storyboard: