如何在調用removeFromSuperview後防止子視圖自我釋放？

Question

我想改變兩個子視圖作爲按鈕被點擊，子視圖是由StoryBoard創建的，每個子視圖都有一個按鈕，點擊按鈕會帶來另一個子視圖並隱藏當前視圖。 但是我發現當子視圖調用removeFromSuperview（）時，它會自動發佈，如果我想在以後使用這個子視圖，我需要一個var來指向它。 這裏是我的代碼：

class ViewController: UIViewController { 

    @IBOutlet weak var secondView: UIView! 
    @IBOutlet weak var firstView: UIView! 
    var temp1: UIView? 
    var temp2: UIView? 
    override func viewDidLoad() { 
     super.viewDidLoad() 
     // Do any additional setup after loading the view, typically from a nib. 
     temp1 = firstView 
     temp2 = secondView 
     secondView.removeFromSuperview() 
    } 
    @IBAction func moveToSecond(_ sender: UIButton) { 
     firstView.removeFromSuperview() 
     view.insertSubview(secondView, at: 0) 
     secondView.isUserInteractionEnabled = true 
    } 
    @IBAction func moveToFirst(_ sender: UIButton) { 
     secondView.removeFromSuperview() 
     view.insertSubview(firstView, at: 0) 
     firstView.isUserInteractionEnabled = true 
    } 
} 

沒有兩種溫度變種，子視圖將removeFromSuperview後釋放，並導致未來insertSubview崩潰，因爲它是零。 那麼，如何防止子視圖自動釋放？ 有沒有另外一種方法來改變StoryBoard優雅創建的兩個子視圖？

我的錯誤，我沒有注意到插座是弱的，一切都合理，removeFromSuperview時，沒有強點留給子視圖，比它自動釋放。

Answer 1

您可以使用@IBOutlet var secondView: UIView!來創建視圖的強引用。但根據您的要求，我建議不要從超級視圖中刪除它。而不是你應該隱藏和顯示需要的視圖如下。

class ViewController: UIViewController { 

@IBOutlet var secondView: UIView! 
@IBOutlet var firstView: UIView! 
override func viewDidLoad() { 
    super.viewDidLoad() 
    // Do any additional setup after loading the view, typically from a nib. 
    secondView.isHidden = true 
} 
@IBAction func moveToSecond(_ sender: UIButton) { 
    firstView.isHidden = true 
    secondView.isHidden = false 
    secondView.isUserInteractionEnabled = true 
} 
@IBAction func moveToFirst(_ sender: UIButton) { 
    secondView.isHidden = true 
    firstView.isHidden = false 
    firstView.isUserInteractionEnabled = true 
} 
} 

Answer 2

假設您的兩個視圖位於上方，具有相同的寬度和高度。在viewDidLoad中。首先將firstView設置爲front，secondView設置爲back。一旦按鈕點擊，我把第二個視圖放在前面，第一個視圖放回去，如此類推。

import UIKit 

class ViewController1: UIViewController { 

    @IBOutlet var secondView: UIView! 
    @IBOutlet var firstView: UIView! 

    override func viewDidLoad() { 
     super.viewDidLoad() 

     self.view.bringSubview(toFront: firstView) 
     self.view.sendSubview(toBack: secondView) 
    } 
    @IBAction func moveToSecond(_ sender: UIButton) { 
     self.view.bringSubview(toFront: secondView) 
     self.view.sendSubview(toBack: firstView) 
    } 
    @IBAction func moveToFirst(_ sender: UIButton) { 
     self.view.bringSubview(toFront: firstView) 
     self.view.sendSubview(toBack: secondView) 
    } 
} 

如果你的兩個子視圖的視圖位於不同的位置。那麼你需要隱藏相應的按鈕另一種觀點點擊

 class ViewController: UIViewController { 

     @IBOutlet var secondView: UIView! 
     @IBOutlet var firstView: UIView! 
     override func viewDidLoad() { 
      super.viewDidLoad() 
      secondView.isHidden = true 
      firstView.isUserInteractionEnabled = true 
     } 
     @IBAction func moveToSecond(_ sender: UIButton) { 
      firstView.isHidden = true 
      secondView.isHidden = false 
      secondView.isUserInteractionEnabled = true 
     } 
     @IBAction func moveToFirst(_ sender: UIButton) { 
      secondView.isHidden = true 
      firstView.isHidden = false 
      firstView.isUserInteractionEnabled = true 
     } 

}