[英]back button at root controller of uinavigationcontroller
我有一個帶有根視圖控制器的UINavigationController應用程序,每次我將視圖控制器推入堆棧時。 假設堆棧是ABCD,其中A是此處的根視圖控制器。 問題是,當我在視圖控制器D上執行popToRootViewController時,它返回到A,但是A上有一個后退按鈕。 當我單擊背面時,背面滑入並消失,為什么會發生這種情況?
編輯:我實際上是我的UINavigationController的子類,以便我可以如下設置我的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:
因此,在我設置了rootViewController並推送了一個viewController並嘗試從該視圖調用popToRootViewController之后,一切正常。 但是,如果我在第二個viewController之后推另一個viewController,然后調用popToRootViewController,現在我可以看到根上的那個奇怪的后退按鈕。
我也面臨同樣的問題。 因此,在您的根控制器中,將leftBarButtonItem分配為nil。
self.navigationItem.leftBarButtonItem = nil;
如果您的根控制器在程序中重用。 然后,您需要檢查->
BOOL needBackBarButton = (1 < [self.navigationController.viewControllers count]) ? YES : NO ;
if (! needBackBarButton)
{
self.navigationItem.leftBarButtonItem = nil;
}
對於其他控制器
if (needBackBarButton)
{
// Create custom navigationItem here.
}
else
{
self.navigationItem.leftBarButtonItem = nil;
}
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