I wanted to create a very simple method that switches between views in a view based application. For some reason, when the views are switched, the first view is removed and instead of viewing the second view, I see a white screen.
This is my method:
FirstViewController *firstViewController = [[FirstViewController alloc] initWithNibName:#"FirstViewController" bundle:nil];
self.view = firstViewController.view;
[firstViewController.view removeFromSuperview];
[firstViewController release];
secondViewController = [[SecondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
self.view = secondViewController.view;
I don't know why it is happening because I know that the second view's ViewDidLoad method is called (I put a NSLog there) - but the second view is not seen!
Any suggestions?
Thanks in advance,
Sagiftw
viewDidLoad's executing because initWithNibName:bundle: calls it. That doesn't mean that the view's actually being displayed.
I usually use this (removing initialisation/release logic):
[self.view addSubview: firstViewController.view];
[firstViewController.view removeFromSuperview];
[self.view addSubview: secondViewController.view];
Related
When I push cancel button in the third view, I want to go back to the first view directly.
I also want to remove the second view.
How can I do that?
This is the code.
// this part is in the first view.
self.second = [SecondController alloc] init];
[self.view addSubview:second.view];
// this part is in the second view.
ThirdController *thirdController = [[ThirdController alloc] initWithStyle:UITableViewStyleGrouped];
self.navigationController = [UINavigationController alloc] initWithRootViewController:thirdController];
[self.view addSubview:navigationController.view];
// this part is in the third view.
- (void)cancel {
[self.view removeFromSuperview]; // this only goes to the second view.
}
EDIT:
Can I use popToViewController in called contoller? My app crashes.
I thought popToViewController can be used only in calling controller.
And popToViewController is used when it was pushed.
I did add not push.
[self.navigationController popToViewController:[[self.navigationController viewControllers] objectAtIndex:0] animated:YES];
popToViewController:animated: is a UINavigationController method that you use when popping view controllers off the navigation controller stack. It doesn't fit for this scenario.
This user is adding subviews, not pushing them on a navigation controller stack.
As a note, it appears as a matter of design you should be using a navigation controller with the first view as the root controller, then the second pushed on the stack, and the third pushed on the stack. Then all you have to do is [self.navigationController popToRootViewControllerAnimated:YES].
I think this will work if you want to keep your current architecture:
// this part is in the third view.
- (void)cancel {
// remove the second view (self.view.superview) from the first view
[self.view.superview removeFromSuperView];
// can't recall, possibly you still need to remove the third view, but i think removing the superview will do it.
// [self.view removeFromSuperView];
}
If you prefer to try the UINavigationController route, then the easiest path is to create a new project in Xcode and select the type for a Navigation-Based Application or a Master-Detail Application. This will create a UINavigationController in a nib and add it to your window. You can then set the root view controller in Interface Builder to your FirstViewController class.
If you prefer to create the UINavigationController in code, then that is also possible. I show that below, along with the rest of the code you need, regardless of whether you create your UINavigationController in a nib in IB or in code.
I also recommend reading the View Controller Programming Guide for iOS.
In your app delegate or some other code:
-(void)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions [
// I would recommend setting up the UINavigationController and FirstViewController as IBOutlets in your nib, but it can be done in code.
FirstViewController* fvc = [[FirstViewController alloc] initWithNibName:#"FirstView" bundle:nil];
UINavigationController* navController = [[UINavigationController alloc] initWithRootViewController:fvc];
[window addSubView:navController.view];
[window makeKeyAndVisible];
[fvc release];
[navController release];
}
In the first view controller:
SecondViewController* svc = [[SecondViewController alloc] initWithNibName:#"SecondView" bundle:nil];
[self.navigationController pushViewController:svc animated:YES];
[svc release];
In the second view controller:
ThirdViewController* tvc = [[ThirdViewController alloc] initWithNibName:#"ThirdView" bundle:nil];
[self.navigationController pushViewController:tvc animated:YES];
[tvc release];
In the third view controller:
-(void)cancel {
// returns to the first view controller
[self.navigationController popToRootViewControllerAnimated:YES];
}
Use
- (NSArray *)popToViewController:(UIViewController *)viewController animated:(BOOL)animated
to go back to a specific view controller.
Try this:
[self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:1] animated:YES];
This will pop to the view at index 1. Hope that Helps!
// this part is in the third view.
- (void)cancel {
self.first = [SecondController alloc] init];
[self.view addSubview:second.view];
}
And I think if you have you don't need to be worried about removing beneath view, later these will removed.
So I feel like a serious rookie right now, but I have a problem I can't seem to figure out. I have a barebones app, with literally nothing in it except a login screen and a second view containing a tableview. When I add the second view after logging in (I have done this like 4 times before...), the table view goes through its delegates and appears that it's going to load, but something happens. I have enabled my NSZombies, and it appears to be deallocating the new view, right before it appears.
After tracing through it, and building up again piece by piece, it appears to happen after I wire the table to the view as the datasource/delegate in IB. I have set the view as a UITableViewDelegate, and the methods indeed get fired. Does anyone have any idea what might be causing this behavior?
Have you added the 'second'view to an exisitng view using addSubview: or added it to some form of UINavigationController or UITabBarController? When you do this it will automatically increase the retain count and whatever code you have releasing the view won't cause is to be deallocated.
In my AppDelegate application:didFinishLaunchingWithOptions I have something like;
LoginViewController *login = [[LoginViewController alloc] init];
[login setDelegate:self];
loginNavController = [[UINavigationController alloc]
initWithRootViewController:login];
[window addSubview:[loginNavController view]];
And then once login has occured (and succeeded using a protocol/delegate to send the message back to AppDelegate) I call this code;
UIViewController *newView1 = [[UIViewController alloc] init];
UIViewController *newView2 = [[UIViewController alloc] init];
UIViewController *newView3 = [[UIViewController alloc] init];
myTabBarController = [[UITabBarController alloc] init];
myNavController = [[UINavigationController alloc]
initWithRootViewController:newView1];
// nav controller now retaining
[newView1 release];
NSArray *viewControllers = [NSArray arrayWithObjects:myNavController,
newView2,
newView3,
nil];
[myTabBarController setViewControllers:viewControllers animated:YES];
[[myTabBarController view] setFrame:[[UIScreen mainScreen] applicationFrame]];
[window addSubview:[tabBarController view]];
// tab bar controller now retaining
[newView2 release];
[newView3 release];
// remove login from application
[[loginNavController view] removeFromSuperview];
The AppDelegate has the following declared in the header file;
LoginViewController *loginViewController;
UITabBarController *myTabBarController;
UINavigationController *myNavController;
In the dealloc method for the AppDelegate these are released.
This gives me my login page and then when that has processed my views with a top nav all controlled using the bottom tab bar.
Hope this helps in some way.
You have either too many release (or autorelease) calls - or not enough retain calls - in your view loading/transitioning code, but it's impossible to be more specific without seeing that code.
What's probably happening is the autorelease pool is being flushed between your view loading and your view being shown, and that's what's leading the behaviour you describe.
As you guess am still a newbie, getting my head around iphone development.
I am just trying out basic view loading on demand, which i cant get to work
I have an app, with 2 view controllers, each view controller connected a different nib file.
I am trying to switch between view manually; there is no navigation control involved.
How can i manually push the second view to the first view?
self.navigationController pushViewController wont work since there is no navigation controller.
How else can I push the second view on top of the first view and destroy the first view; and ofcourse vice versa?
I have done this in the first view's button action:
SecondView *sv=[[SecondView alloc] initWithNibName:#"SecondView" bundle:nil];
[self.navigationController pushViewController:sv animated:YES];
obviously, it didn't work.
window addSubView didn't work either, because the first view controller is the root view controller (not sure i said that right). In other words, when i run the app, the first view is what I see with a button that is supposed to load the second view.
I have spent hours searching for a simple example, and I couldn't find any.
Any suggestions?
in the first view controller you need this:
- (IBAction)pushWithoutViewController:(id)selector {
NextNavigationController *page = [[NextNavigationController alloc] initWithNibName:NextNavigationController bundle:nil];
CGRect theFrame = page.view.frame;
theFrame.origin = CGPointMake(self.view.frame.size.width, 0);
page.view.frame = theFrame;
theFrame.origin = CGPointMake(0,0);
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.8f];
page.view.frame = theFrame;
[UIView commitAnimations];
[self.view addSubview:page.view];
[page release];
}
and then link it to the button in nib. :)
try :
SecondView *sv=[[SecondView alloc] initWithNibName:#"SecondView" bundle:nil];
[self presentModalViewController:sv animated:YES];
IF you have first xib and you want to give navigation to another controller then you have to declare navigation in to appdelegate.m
write following code to app
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:self.viewController];
self.window.rootViewController = navController;
then in ViewController.m
- (IBAction)NextButtonClicked:(id)sender
{
yourNextViewController *objyourNextViewController = [[yourNextViewController alloc] initWithNibName:#"yourNextViewController" bundle:nil];
[self.navigationController pushViewController:objStartUpViewController animated:TRUE];
}
I'm having a strange problem with adding a UINavigationController to my iPhone application. I add the controller as follows:
myViewController *viewController = [[myViewController alloc] initWithNibName:#"myView" bundle:nil];
myNavigationViewController *navigationController = [[myNavigationViewController alloc] initWithRootViewController:viewController];
UIView *finalView = myeNavigationViewController.view;
[self.view addSubview:finalView];
All seems to work as planned except I get a weird white space at the top of my view between the status bar and the UINavigationController title bar.
alt text http://www.andrewskinner.name/problem.png
I've searched online but don't really know what to search for. Has anyone else had this problem? Can you point me in the direction of some help?
Thanks in advance.
What does the line
UIView *finalView = myeNavigationViewController.view;
add to the code? It's redundant as you can add the view directly without assigning it to a UIView first - plus it's incorrect as it references the myNavigationController and not navigationController..
I tend to do this
myViewController *viewController = [[myViewController alloc] initWithNibName:#"myView" bundle:nil];
myNavigationViewController *navigationController = [[myNavigationViewController alloc] initWithRootViewController:viewController];
[navigationController.view setFrame: [self.view bounds]];
navigationController.delegate = self;
[self.view addSubview:[navigationController view]];
Setting the frame to the bounds also removes the white space at the top you were asking about.
Check out the answers in this question:
Not sure why UIView is being nudged up by around 10px
The issue is that UINavigationController ideally should be the direct subView of UIWindow. It will position and size right by itself. When you add UINavigationController into another custom view of a UIWindow subview, you need to take care of the position and size of this custom view by taking into account whether the status bar is shown or not in the UIWindow.
My suggestion is to make the custom view as a subclass of UINavigationController:
mySubClass_NavigationController*nav=[[mySubClass_NavigationController alloc] initWithRootViewController:viewController ];
[myUIWindow addSubview:nav.view];
and inside the mySubClass_NavigationController, you can do all the customization that you are doing now in your self (whatever that controller is).
I struggled with this for a while too using very similar code to the op's and also had a white bar above my navigation controller.
My problem occurred when adding the UINavigationController as a view in a UITabController. The space in my case was caused by the UINavigationBar part of the UINavigationController taking into account the status bar and it was actually overlapping part of the view that I was trying to show in the UINavigationController.
This is the code I ended up with in loadView in one of my UITabBarController view controllers.
SomeUITableViewController *screenList = [[SomeUITableViewController alloc] init];
UINavigationController *navController = [[UINavigationController alloc]
initWithRootViewController:screenList];
CGRect frame = [[navController navigationBar] frame];
frame.origin.y = 0; // Was 20, set to 0 to not take into account the status bar.
[[navController navigationBar] setFrame:frame];
[self setView:[navController view]];
There's some more information at http://discussions.apple.com/message.jspa?messageID=7890362.
There is an obscure property in IB called "Hides Bottom Bar on Push". Just check it. It solved the problem for me.
Maybe you have somehow gotten yourself two UIViews,
each with a status bar. Check the xib.
I've got a button on a view. When I click on it, it should load another view, one with a novigation controller. So far I've got this, the button calls this method:
-(IBAction)loadOptionsView:(id)sender {
if (self.optionsRootController == nil) {
//optionsRootController is declared as: UINavigationController *optionsRootController;
optionsRootController = [[UINavigationController alloc] init];
//Options is a UIViewController
Options *myOptions = [[Options alloc] initWithNibName:#"OptionsMenu" bundle:nil];
[optionsRootController pushViewController:myOptions animated:NO];
[myOptions release];
}
[self.view addSubview:optionsRootController.view];
}
What happens when I click the button is that it loads the xib file OptionsMenu on top of the current screen, but there's a gap at the top of the size of the status bar, so I can see the view below. Any help? What's the right method to load a new view that contains a navigation controller?
Thank you all!
I solved this issue by placing after:
[optionsRootController pushViewController:myOptions animated:NO];
this line:
[optionsRootController.view setFrame: [self.view bounds]];
Nice and easy!
I think UINavigationController's designated initializer is
- (id) initWithRootController:(UIViewController *)rootController
So your code above would be better expressed as
//optionsRootController is declared as: UINavigationController *optionsRootController;
//Options is a UIViewController
Options *myOptions = [[Options alloc] initWithNibName:#"OptionsMenu" bundle:nil];
optionsRootController = [[UINavigationController alloc] initWithRootController: myOptions];
[myOptions release];
Is the VIew in your nib the right size for the whole screen? Try turning off the simulated status bar in IB.