uinavigationcontroller 根控制器的后退按钮

Question

我有一个带有根视图控制器的 UINavigationController 应用程序，每次我将视图控制器推送到堆栈时。假设堆栈是 A B C D 其中 A 是这里的根视图控制器。问题是当我在视图控制器 D 并执行 popToRootViewController 时，它返回到 A 但 A 上有一个后退按钮。当我点击背面时，背面只是滑入并消失，为什么会发生这种情况？

编辑：我实际上是对我的 UINavigationController 进行子类化，以便我可以按如下方式设置我的 rootViewController：

#import "CustomNavigationController.h"

@implementation CustomNavigationController

@synthesize fakeRootViewController;

//override to remove fake root controller
-(NSArray *)viewControllers {
    NSArray *viewControllers = [super viewControllers];     
if (viewControllers != nil && viewControllers.count > 0) {  
NSMutableArray *array = [NSMutableArray arrayWithArray:viewControllers];        
[array removeObjectAtIndex:0];  
    return array;   } 
    return viewControllers; }

//override so it pops to the perceived root
- (NSArray *)popToRootViewControllerAnimated:(BOOL)animated {
    //we use index 0 because we overrided “viewControllers”
    ((UIViewController *)[self.viewControllers objectAtIndex:0]).navigationItem.hidesBackButton = YES;
    return [self popToViewController:[self.viewControllers objectAtIndex:0] animated:animated]; }

//this is the new method that lets you set the perceived root, the previous one will be popped (released)
-(void)setRootViewController:(UIViewController *)rootViewController {
    rootViewController.navigationItem.hidesBackButton = YES;
    [self popToViewController:fakeRootViewController animated:NO];
    [self pushViewController:rootViewController animated:NO]; }

- (void)dealloc {
    self.fakeRootViewController = nil;
    [super dealloc]; }


-(id)initWithCoder:(NSCoder *)aDecoder{
    self = [super initWithCoder:aDecoder];
    if(self){
        UIViewController *fakeController = [[[UIViewController alloc] init] autorelease];
        self.fakeRootViewController = fakeController;
        NSMutableArray *array = [NSMutableArray arrayWithArray:[super viewControllers]];
        [array insertObject:fakeController atIndex:0];
        self.viewControllers = array;
    }
    return self; }

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use. }

#pragma mark - View lifecycle

/* // Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView { }
*/

/* // Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad]; }
*/

- (void)viewDidUnload {
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil; }

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait); }

@end

更多更新：

所以在我设置我的 rootViewController 然后推送一个 viewController 然后尝试从该视图调用 popToRootViewController 之后，一切正常。但是，如果我在第二个 viewController 之后推送另一个 viewController，然后调用 popToRootViewController，现在我可以在根目录上看到那个奇怪的后退按钮。

Answer 1

我也面临同样的问题。所以在你的根控制器中分配 leftBarButtonItem 等于 nil。

self.navigationItem.leftBarButtonItem = nil;

如果您的根控制器在程序中重用。然后你需要检查 ->

BOOL needBackBarButton = (1 < [self.navigationController.viewControllers count]) ? YES : NO ; 
if (! needBackBarButton)
{
    self.navigationItem.leftBarButtonItem = nil;
}

对于其他控制器

if (needBackBarButton)
{
          // Create custom navigationItem here.
}
else 
{
    self.navigationItem.leftBarButtonItem = nil;
}