在過去的一周中，我為解決如何顯示和消除多個視圖控制器問題而煩惱不已。我創建了一個示例項目，并直接從該項目中粘貼代碼。我有3個視圖控制器及其相應的.xib文件。MainViewController，VC1和VC2。我在主視圖控制器上有兩個按鈕。- (IBAction)VC1Pressed:(UIButton *)sender{ VC1 *vc1 = [[VC1 alloc] initWithNibName:@"VC1" bundle:nil]; [vc1 setModalTransitionStyle:UIModalTransitionStyleFlipHorizontal]; [self presentViewController:vc1 animated:YES completion:nil];}這將打開VC1，沒有任何問題。在VC1中，我有另一個按鈕應該打開VC2，同時關閉VC1。- (IBAction)buttonPressedFromVC1:(UIButton *)sender{ VC2 *vc2 = [[VC2 alloc] initWithNibName:@"VC2" bundle:nil]; [vc2 setModalTransitionStyle:UIModalTransitionStyleFlipHorizontal]; [self presentViewController:vc2 animated:YES completion:nil]; [self dismissViewControllerAnimated:YES completion:nil];} // This shows a warning: Attempt to dismiss from view controller <VC1: 0x715e460> while a presentation or dismiss is in progress!- (IBAction)buttonPressedFromVC2:(UIButton *)sender{ [self dismissViewControllerAnimated:YES completion:nil];} // This is going back to VC1. 我希望它返回到主視圖控制器，同時應從內存中永久刪除VC1。僅當我單擊主控制器上的VC1按鈕時，才會顯示VC1。主視圖控制器上的另一個按鈕也應該能夠直接繞過VC1來顯示VC2，并且在VC2上單擊一個按鈕時應回到主控制器。沒有長時間運行的代碼，循環或任何計時器。只需裸露電話即可查看控制器。
3 回答
HUX布斯
TA貢獻1876條經驗 獲得超6個贊
我認為您誤解了有關iOS模式視圖控制器的一些核心概念。當您關閉VC1時，任何由VC1呈現的視圖控制器也將被關閉。Apple希望模式視圖控制器以堆疊的方式流動-在您的情況下，VC2由VC1提供。一旦您從VC1提供VC2，就將VC1解雇，這簡直是一團糟。為了實現所需的功能，在VC1退出后，buttonPressedFromVC1應該立即使mainVC出現在VC2中。我認為，沒有代表就可以實現這一目標。大致情況：
UIViewController presentingVC = [self presentingViewController];
[self dismissViewControllerAnimated:YES completion:
^{
[presentingVC presentViewController:vc2 animated:YES completion:nil];
}];
注意self.presentingViewController存儲在其他變量中，因為在vc1關閉自身之后，您不應對其進行任何引用。
慕田峪9158850
TA貢獻1794條經驗 獲得超8個贊
Swift中的示例，描繪了上述代工廠的說明和Apple的文檔：
基于Apple的文檔和上述鑄造廠的說明（糾正了一些錯誤），使用委托設計模式的presentViewController版本：
ViewController.swift
import UIKit
protocol ViewControllerProtocol {
func dismissViewController1AndPresentViewController2()
}
class ViewController: UIViewController, ViewControllerProtocol {
@IBAction func goToViewController1BtnPressed(sender: UIButton) {
let vc1: ViewController1 = self.storyboard?.instantiateViewControllerWithIdentifier("VC1") as ViewController1
vc1.delegate = self
vc1.modalTransitionStyle = UIModalTransitionStyle.FlipHorizontal
self.presentViewController(vc1, animated: true, completion: nil)
}
func dismissViewController1AndPresentViewController2() {
self.dismissViewControllerAnimated(false, completion: { () -> Void in
let vc2: ViewController2 = self.storyboard?.instantiateViewControllerWithIdentifier("VC2") as ViewController2
self.presentViewController(vc2, animated: true, completion: nil)
})
}
}
ViewController1.swift
import UIKit
class ViewController1: UIViewController {
var delegate: protocol<ViewControllerProtocol>!
@IBAction func goToViewController2(sender: UIButton) {
self.delegate.dismissViewController1AndPresentViewController2()
}
}
ViewController2.swift
import UIKit
class ViewController2: UIViewController {
}
基于上述代工廠的解釋（更正了一些錯誤），使用委托設計模式的pushViewController版本：
ViewController.swift
import UIKit
protocol ViewControllerProtocol {
func popViewController1AndPushViewController2()
}
class ViewController: UIViewController, ViewControllerProtocol {
@IBAction func goToViewController1BtnPressed(sender: UIButton) {
let vc1: ViewController1 = self.storyboard?.instantiateViewControllerWithIdentifier("VC1") as ViewController1
vc1.delegate = self
self.navigationController?.pushViewController(vc1, animated: true)
}
func popViewController1AndPushViewController2() {
self.navigationController?.popViewControllerAnimated(false)
let vc2: ViewController2 = self.storyboard?.instantiateViewControllerWithIdentifier("VC2") as ViewController2
self.navigationController?.pushViewController(vc2, animated: true)
}
}
ViewController1.swift
import UIKit
class ViewController1: UIViewController {
var delegate: protocol<ViewControllerProtocol>!
@IBAction func goToViewController2(sender: UIButton) {
self.delegate.popViewController1AndPushViewController2()
}
}
ViewController2.swift
import UIKit
class ViewController2: UIViewController {
}
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