cocoa-touch - 未调用 UINavigationControllerDelegate 方法(github 上的演示代码)

Question

弹出到不支持当前方向的 View Controller 时，未调用 UINavigationControllerDelegate 方法。

我有一个 UINavigationController 作为我的应用程序的 Root View Controller (我的 Storyboard中的初始 View Controller )。

假设我用这个来推送一个 ViewController A 来定位:

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

因此我们不支持任何横向模式。最重要的是，让我们用代码推送另一个 ViewController:

@interface B : UIViewController <UINavigationControllerDelegate>
@end

@implementation B
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    return YES;   // any orientation supported
}

- (void)viewDidLoad {
    [super viewDidLoad];

    AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    UINavigationController *nc = (UINavigationController*)appDelegate.window.rootViewController;
    nc.delegate = self;
}

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
    // not always called...
}

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
    // not always called...
}
@end

现在，如果我的 iPhone 是纵向的，我通过一些触摸事件将 View Controller B 推到 A 上，然后触摸导航栏中的“后退”按钮，一切都很好，并且调用了委托(delegate)方法(我在那里做了一些事情)。

但是，如果当我查看 View B 时，我旋转到横向，然后点击后退按钮，则不会调用这些委托(delegate)方法!如果有时调用方法但不调用其他方法，那么为 UINavigationController 设置委托(delegate)有什么意义？我肯定做错了什么。

我尝试将委托(delegate)放在其他类中，例如 AppDelegate 或我的 MainView，没有任何变化。

有任何想法吗 ？

演示代码: git://github.com/malaba/NavBarTest.git

从一个基本的主从模板，如上修改。

如何表明我的观点？这是一步一步:

在主视图中添加一些行(+ 右上角)

然后触摸一条线进入详细信息 View

请参阅显示的登录输出

点击返回按钮(标记为“Master”)，再次显示日志。

现在尝试在细节 View 中旋转 iPhone(或模拟器)，然后“返回”并查看 没有日志出现？!

Answer 1

嗨，这对我来说也是一个棘手的问题，直到我看到这个想法:http://www.hanspinckaers.com/custom-action-on-back-button-uinavigationcontroller

当 NavigationController 和 TopViewController 具有相同的方向时，IOS 使用以下代码创建以下调用序列(单点触控)

SomeTopViewController ViewWillDisappear

WillShowViewController viewController:新的 TopViewController

SomeTopViewController ViewDidDisappear

DidShowViewController viewController:新的 TopViewController

当 NavigationController 和 TopViewController 有 不同方向然后 NavigationController 委托(delegate)是 不是 如你所描述的那样调用。因此调用顺序为:

SomeTopViewController ViewWillDisappear

SomeTopViewController ViewDidDisappear

以下代码通过覆盖 NavigationController 的 PopViewControllerAnimated 来重现 ios 调用序列:

public class MyNavigationControllerDelegate : UINavigationControllerDelegate {
  public MyNavigationControllerDelegate( ) : base() {}

  public bool WasCalled {get;set;}  // flag that we use to track whether iOS calls the handlers or we have to 

  public override void WillShowViewController( UINavigationController navigationController, UIViewController viewController, bool animated ) {
    Console.WriteLine( "WillShowViewController viewController: {0}", viewController.GetType() );
    WasCalled = true;  // signal that we have been called
    //.….. do your stuff
  }

  public override void DidShowViewController( UINavigationController navigationController, UIViewController viewController, bool animated ) {
    Console.WriteLine( "DidShowViewController viewController: {0}", viewController.GetType() );
    //.….. do your stuff
  }
}

public partial class MyNavigationController : UINavigationController {
  MyNavigationControllerDelegate navigationControllerDelegate;

  public override void ViewDidLoad() {
    base.ViewDidLoad();
    navigationControllerDelegate = new MyNavigationControllerDelegate( viewSelectionControl );
    Delegate = navigationControllerDelegate;
  }

public override UIViewController PopViewControllerAnimated( bool animated ) {
  Console.WriteLine( "PopViewControllerAnimated TopViewController.GetType: {0}", TopViewController.GetType() );
  navigationControllerDelegate.WasCalled = false;   // reset flag before we start the popsequence

  UIViewController ctrl = base.PopViewControllerAnimated( animated );

  AppDelegate.MainWindow.BeginInvokeOnMainThread( delegate {
    if( !navigationControllerDelegate.WasCalled )  {   // if iOS did not call the delegate handler then we must do it
      Delegate.WillShowViewController( this, TopViewController, animated );
      navigationControllerDelegate.WasCalled = false;  // reset flag to be used in the next DidShowViewController step of the popsequence
      }
  } );

  Thread t = new Thread( () => RunPop(animated) );
  tt.Start();

  return ctrl;
}

void RunPop(bool animated) {
  Thread.Sleep( 500 );
  AppDelegate.MainWindow.BeginInvokeOnMainThread( delegate {
    if( !navigationControllerDelegate.WasCalled ) {  // if iOS did not call the delegate handler then we must do it
      Delegate.DidShowViewController(this,TopViewController,animated);
    }
  } );
}

}