ios - 模态视图 Controller - 如何显示和关闭

Question

在过去的一周里，我一直在思考如何通过显示和关闭多个 View Controller 来解决这个问题。我创建了一个示例项目并直接从项目中粘贴代码。我有 3 个 View Controller 及其相应的 .xib 文件。 MainViewController、VC1 和 VC2。我在主视图 Controller 上有两个按钮。

- (IBAction)VC1Pressed:(UIButton *)sender
{
    VC1 *vc1 = [[VC1 alloc] initWithNibName:@"VC1" bundle:nil];
    [vc1 setModalTransitionStyle:UIModalTransitionStyleFlipHorizontal];
    [self presentViewController:vc1 animated:YES completion:nil];
}

这将毫无问题地打开 VC1。在 VC1 中，我有另一个按钮应该打开 VC2 同时关闭 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. 

我希望它回到主视图 Controller ，同时 VC1 应该已经从内存中删除了。只有当我单击主 Controller 上的 VC1 按钮时，VC1 才会出现。

主视图 Controller 上的另一个按钮也应该能够绕过 VC1 直接显示 VC2，并且当单击 VC2 上的按钮时应该返回到主 Controller 。没有长时间运行的代码、循环或任何计时器。只是简单地调用 View Controller 。

Answer 1

中的示例 swift ，描绘了上面代工厂的解释和苹果的文档:

基于Apple's documentation和类型转换厂的
上面的解释(纠正一些错误)，presentViewController
使用委托(delegate)设计模式的版本:

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 {

}

根据上面代工厂的解释(纠正一些错误)，
使用委托(delegate)设计模式的 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 {

}