xcode 4.2에서 iphone의 다단계 탐색

Question

xcode 4.2에서보기 기반 프로젝트를 만들었으며 다양한보기로 이동하기 위해 다중 레벨 탐색을 수행하려고합니다. 내 첫 번째 뷰 클래스는 ViewController 어디 테이블을 표시합니다. On 행을 클릭하면 tabbar가있는 다음 클래스로 이동합니다. 이것에는 3 개의 탭이 있습니다. 첫 번째 탭은 Class BuyerViewController를 사용합니다. 4 개의 버튼이 있습니다. 문제는 버튼을 클릭하면 다음 클래스를 푸시하지 않는다는 것입니다.

ViewController.m

- (void)viewDidLoad 
{ 
self.title=@"Select County"; 
    tView = [[UITableView alloc] init]; //tView is my table view object. 
    tView.frame=CGRectMake(0, 20, 320, 460); 
    [tView setDelegate:self]; 
    [tView setDataSource:self]; 
    [self.view addSubview:tView]; 
} 
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { 
return 1; 
} 
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { 
return [countyArray count]; 
} 
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { 

static NSString *CellIdentifier = @"Cell"; 

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; 
if (cell == nil) { 
    cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; 
} 
cell.textLabel.text = [countyArray objectAtIndex:indexPath.row]; 
return cell; 
} 
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { 
//This works fine and pushes to my next class to show the tabs. 

ShowOptionInTab *showTabbar = [[ShowOptionInTab alloc] initWithNibName:@"ShowOptionInTab" bundle:nil]; 
[self.navigationController pushViewController:showTabbar animated:YES]; 
[showTabbar release]; 
} 

ShowOptionInTab.m

-(void)loadView { 
UIView *contentView = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]]; 
contentView.backgroundColor = [UIColor whiteColor]; 
self.view = contentView; 
[contentView release]; 

BuyerViewController *buyerController = [[BuyerViewController alloc] init ]; 

SellerViewController *sellerController = [[SellerViewController alloc] init]; 

LenderViewController *lenderController = [[LenderViewController alloc] init]; 

buyerController.title=@"Buyer"; 
sellerController.title = @"Seller"; 
lenderController.title = @"Lender"; 

UITabBarController *tabbarController = [[UITabBarController alloc] init]; 

tabbarController.view.frame = CGRectMake(0, 0, 320, 460); 
[tabbarController setViewControllers:[NSArray arrayWithObjects:buyerController, sellerController,lenderController, nil]]; 

[buyerController release]; 
[sellerController release]; 
[lenderController release]; 
[self.view addSubview:tabbarController.view];  
} 

BuyerViewController.m

-(void)viewWillAppear:(BOOL)animated 
{ 
UIButton *quickEstimateButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 

    [quickEstimateButton addTarget:self action:@selector(getTagOfPressedButton:) forControlEvents:UIControlEventTouchUpInside]; 
[quickEstimateButton setTitle:@"QUICK ESTIMATE" forState:UIControlStateNormal]; 
quickEstimateButton.tag=1; 
quickEstimateButton.frame = CGRectMake(10, 50, 150, 40.0); 
[self.view addSubview:quickEstimateButton]; 

//more 3 buttons are added in same way 
} 
-(void) getTagOfPressedButton:(id)sender { 

UIButton *getTagOfButton = (UIButton *)sender; 
int buttonPressedTag = getTagOfButton.tag; 
NSLog(@"TAG==========%d",buttonPressedTag); 
if(buttonPressedTag==1) 
{ 
    NSLog(@"quick estimate pressed"); 
    QuickEstimateViewController *q = [[QuickEstimateViewController alloc] init]; 
    NSLog(@"nav====%@",self.navigationController); //This returns null. 
    [self.navigationController pushViewController:q animated:YES]; 
} 
} 

AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 
     ViewController *overviewViewController = [[ViewController alloc] initWithNibName:@"ViewController_iPhone" bundle:nil]; 
    UINavigationController* navigation = [[UINavigationController alloc] initWithRootViewController:overviewViewController]; 
    navigation.navigationBar.tintColor = [UIColor blackColor]; 
    [overviewViewController release]; 

    [self.window addSubview:[navigation view]]; 
    [self.window makeKeyAndVisible]; 
} 

,

QuickEstimateViewController가 표시되지 않는 이유는 무엇입니까?

Answer 1

당신은 ShowOptionInTab에서 subview로 tabBarController와 뷰의 새로운 객체를 정의하고 또한 새로운 객체 인 BuyerViewController를 정의하기 때문에 navigationController가 QuickEstimateViewController를 푸시하려고 시도하면 null이 될 것입니다. 코드 모양이 이게 ..

BuyerViewController *buyerController = [[BuyerViewController alloc] init ]; 
UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:buyerController]; 

SellerViewController *sellerController = [[SellerViewController alloc] init]; 

LenderViewController *lenderController = [[LenderViewController alloc] init]; 

buyerController.title=@"Buyer"; 
sellerController.title = @"Seller"; 
lenderController.title = @"Lender"; 

UITabBarController *tabbarController = [[UITabBarController alloc] init]; 

tabbarController.view.frame = CGRectMake(0, 0, 320, 460); 
[tabbarController setViewControllers:[NSArray arrayWithObjects:nav, sellerController,lenderController, nil]];