ios - TableViewController 的pushViewController 方法中的navigationController = null (popover)

Question

首先，对不起我的英语。 我正在尝试为 iPad 开发一个带有导航 Controller 的应用程序，该导航 Controller 会在选择“下一步”按钮时推送 View Controller 。但我也想有一个弹出窗口，从导航栏中的按钮调用，允许用户从一个 View Controller “跳转”到另一个 View Controller ，使用 tableView:didSelectRowAtIndexPath: 和 pushViewController:animated: 方法推送它，但是它不工作。

总结:

标签栏 -> 在 FirstViewController 和 SecondViewController 之间切换(工作正常)

导航栏(按钮Next) -> 在SecondViewController、FirstSlideController 和SecondSlideController 之间切换(也不错)

弹出框 -> 用户选择 SecondViewController、FirstSlideController 或 SecondSlideController(问题出在这里!)

代码:

AppDelegate

UIViewController *viewController1 = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];
UINavigationController *navigationController1 = [[UINavigationController alloc] initWithRootViewController:viewController1];
UIViewController *viewController2 = [[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil];
UINavigationController *navigationController2 = [[UINavigationController alloc] initWithRootViewController:viewController2];
self.tabBarController = [[UITabBarController alloc] init];
self.tabBarController.viewControllers = @[navigationController1, navigationController2];
self.window.rootViewController = self.tabBarController;
[self.window makeKeyAndVisible];
return YES;

TableViewController(popover) 的 didSelectRowAtIndexPath 方法:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{

if(indexPath.row == 0){
 FirstSlideController *detailViewController = [[FirstSlideController alloc] initWithNibName:@"FirstSlideController" bundle:nil];
 [self.navigationController pushViewController:detailViewController animated:YES];
}

else if(indexPath.row == 1){
    SecondSlideController *detailViewController = [[SecondSlideController alloc] initWithNibName:@"SecondSlideController" bundle:nil];
    [self.navigationController pushViewController:detailViewController animated:YES];
}
else{
    SecondViewController *detailViewController = [[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil];
    [self.navigationController pushViewController:detailViewController animated:YES];
}

SecondViewController(由 maros 建议的委托(delegate))

-(void) showPopover:(id) sender
{
   TableViewController *PopoverView = [[TableViewController alloc] initWithNibName:@"TableViewController" bundle:nil];
   self.popOver = [[UIPopoverController alloc] initWithContentViewController:PopoverView];
   self.popOver.delegate = self;
   [self.popOver presentPopoverFromBarButtonItem:self.navigationItem.leftBarButtonItem permittedArrowDirections: UIPopoverArrowDirectionUp animated: YES];
}

我尝试打印 self.navigationController，它说它为空。如果有任何帮助，我将不胜感激。

谢谢。

Answer 1

Presnented UIPopoverController 没有被推送到它被呈现的 View Controller 中的导航堆栈上。它是一个单独的 View Controller 。 因此，弹出框内的 navigationController 为 nil。

我建议您创建一个委托(delegate) MyNavigationPopoverDelegate(创建弹出窗口的类 (PopoverController)。将它的实例作为委托(delegate)传递给 TableView Controller 。

当用户点击popover中的某个按钮后，调用delegate的方法来处理按钮点击(myNavigationPopover:(UIPopoverController*)popover clickedButtonAtIndex:(NSInteger)buttonIndex)。

然后也许可以解雇代表？

最后随心所欲地更改导航! :)

@protocol MyNavigationPopoverDelegate
- (void) myNavigationPopover:(UIPopoverController*)popover clickedButtonAtIndex:(NSInteger)buttonIndex;
@end

@interface TableViewController : UITableVieController // your viewController in popover
... // your code
@property (nonatomic, weak) NSObject <MyNavigationPopoverDelegate> * delegate;
... // your code
@end

@implementation TableViewController
...
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    [self.delegate myNavigationPopover:self clickedButtonAtIndex:indexPath.row];
}
...
@end

// defines that SecondViewController implements the delegate's method
@interface SecondViewController <MyNavigationPopoverDelegate> : UIViewController 
  // your code
@end

// code where you presenting popover 
@implementation SecondViewController

// This is the method that is executed after your button press and it is responsible for presenting a popover
- (void) presentPopover{
   ...
   myPopover.delegate = self; // setting the delegate
   [myPopover presentPopoverFromXXX ...]; // however you present it
   ...
}

 - (void) myNavigationPopover:(UIPopoverController*)popover clickedButtonAtIndex:(NSInteger)buttonIndex
 {
 UINavigationController *currentNavigationController = ; // get the navigation controller from the tab bar

 if(buttonIndex == 0){
      FirstSlideController *detailViewController = [[FirstSlideController alloc] initWithNibName:@"FirstSlideController" bundle:nil];
      [currentNavigationController pushViewController:detailViewController animated:YES];
 }

 else if(buttonIndex == 1){
      SecondSlideController *detailViewController = [[SecondSlideController alloc] initWithNibName:@"SecondSlideController" bundle:nil];
      [currentNavigationController pushViewController:detailViewController animated:YES];
 }
 else{
      SecondViewController *detailViewController = [[SecondViewController alloc]         initWithNibName:@"SecondViewController" bundle:nil];
      [currentNavigationController pushViewController:detailViewController animated:YES];
 }
}

@end;