UINavigationController在運行編譯時不顯示

Question

編輯：工作，請參閱下面的代碼。

在一個應用程序上工作，現在我有AppDelegate類和一個自定義UINavigationController類。我現在的代碼非常簡單，我覺得我已經正確設置了XIB。構建成功，沒有錯誤。但是當應用程序啓動時，導航控制器不會顯示。我沒有看到導航欄和表格視圖。我看到的只是一個空白的屏幕。這裏是我的大部分代碼：

// 
// FTPPhotosAppDelegate.h 
// FTPPhotos 
// 
// Created by Aaron McLeod on 11-05-30. 
// Copyright 2011 __MyCompanyName__. All rights reserved. 
// 

#import <UIKit/UIKit.h> 
#import "RootViewController.h" 

@interface FTPPhotosAppDelegate : NSObject <UIApplicationDelegate> { 
    UINavigationController *navigationController; 
    RootViewController *rootViewController; 
} 

@property (nonatomic, retain) UINavigationController *navigationController; 
@property (nonatomic, retain) IBOutlet UIWindow *window; 

@property (nonatomic, retain) RootViewController *rootViewController; 

@end 


// 
// FTPPhotosAppDelegate.m 
// FTPPhotos 
// 
// Created by Aaron McLeod on 11-05-30. 
// Copyright 2011 __MyCompanyName__. All rights reserved. 
// 

#import "FTPPhotosAppDelegate.h" 

@implementation FTPPhotosAppDelegate 


@synthesize window=_window; 

    @synthesize navigationController, rootViewController; 

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 
    navigationController = [[UINavigationController alloc] init]; 

    rootViewController = [[RootViewController alloc] init]; 
    [self.navigationController pushViewController:rootViewController animated:NO]; 
    [self.window addSubview:[self.navigationController view]];  
    [self.window makeKeyAndVisible]; 
    return YES; 
} 


@interface RootViewController : UITableViewController<UIImagePickerControllerDelegate> { 
    NSMutableArray *photos; 
    UIImagePickerController *picker; 
    UIBarButtonItem *addPhotoButton; 
} 

@property (nonatomic, retain) NSMutableArray *photos; 
@property (nonatomic, retain) UIImagePickerController *picker; 
@property (nonatomic, retain) IBOutlet UIBarButtonItem *addPhotoButton; 

- (void) loadPhotos; 
- (IBAction) addPhoto; 
- (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize; 
@end 


#import "RootViewController.h" 

@implementation RootViewController 
@synthesize photos, picker, addPhotoButton; 

- (void)viewDidLoad 
{ 
    self.photos = [[NSMutableArray alloc] initWithCapacity:50]; 
    [self loadPhotos]; 
    [super viewDidLoad]; 
} 

任何想法？以下是XIB，

的屏幕截圖。

讓我知道你是否需要更多信息。

Answer 1

取而代之的是一個根視圖控制器，使它成爲UINavigationController *navigationController。

然後在applicationDidFinishLaunching，說

navigationController = [[UINavigationController alloc]init]; 
FirstViewController *firstView = [FirstViewController alloc]init]; 
[self pushViewController:firstView animated:NO]; 
firstView.title = @"TITLE"; 
[self addSubview:navigationController.view]; 

編輯：一些示例代碼我在我的一個應用

AppDelegate.h

#import <UIKit/UIKit.h> 

@interface DragonAge2AppDelegate : NSObject <UIApplicationDelegate> { 
UIWindow *window; 
UINavigationController *navigationController; 
} 

@property (nonatomic, retain) IBOutlet UIWindow *window; 

@end 

AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {  
TitleClass *titlePage = [[TitleClass alloc]init]; 

navigationController = [[UINavigationController alloc]init]; 
titlePage.title = @"Dragon Age 2"; 
[navigationController pushViewController:titlePage animated:NO]; 
[titlePage release]; 

// Override point for customization after application launch. 
[window addSubview:navigationController.view]; 
[self.window makeKeyAndVisible]; 

return YES; 
} 

Answer 2

您需要檢查一些要點：

• 在執行application:didFinishLaunchingWithOptions:的代碼，當你運行應用程序？在此代碼中添加一個NSLog(@"app launched")或在其中設置一個斷點來檢查它。如果未被調用，則您的FTPPhotosAppDelegate對象可能未被設置爲XIB中的UIApplication單身人員的代表（如果您使用標準模板創建應用程序，此連接應默認完成），但值得檢查
• 您的AppDelegate的navigationControllerIBOutlet已正確連接到XIB中的實際UINavigationController？檢查（使用NSLog或斷點）它不是nil。
• 與XIB中的UINavigationController對象的視圖IBOutlet相同：請檢查它是否正確連接，而不是nil。