I'm having troubles with an UINavigationController which viewControllers property is null after tapping Back on a previously pushed view controller.
The root view controller in AppDelegate is defined with that code:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
self.window.backgroundColor = [UIColor whiteColor];
StartViewController *startVc = [[StartViewController alloc] initWithNibName:#"StartViewController" bundle:nil];
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:startVc];
self.window.rootViewController = navigationController;
[self.window makeKeyAndVisible];
return YES;
}
At StartViewController I'm hiding the navigation bar within - (void)viewWillAppear:(BOOL)animated where I've also a UIButton instance where I push the next view controller when tapping with that code:
- (IBAction)buttonTapped:(id)sender {
PhilosophyViewController *philsophyVc = [[PhilosophyViewController alloc] initWithNibName:#"PhilosophyViewController" bundle:nil];
[self.navigationController pushViewController:philsophyVc animated:YES];
}
I'm heading over to the next view as expected. But when tapping the Back button at the navigation bar, the previous view (StartViewController) is empty and when checking the viewControllers property of the navigation controller - it is null?
Any idea?
Thanks in advance.
The back button of the pushed viewController can be hooked up to an IBAction
-(IBAction)backButtonPressed:(id)sender{
[self.navigationController popViewControllerAnimated:YES];
}
This should pop you back to the previous view controller front the stack.
Hope this helps.
Related
Please, help to understand the navigation. I'm working with xibs. The scheme is: https://www.dropbox.com/s/o82fxpte0hmyxcq/Scheme_Simple.jpg .
Here's my code :
#implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
self.window.backgroundColor = [UIColor whiteColor];
FirstViewController *firstViewController = [[firstViewController alloc] initWithNibName:#"firstViewController" bundle:nil];
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:firstViewController];
self.window.rootViewController = navigationController;
[self.window makeKeyAndVisible];
return YES;
}
#implementation FirstViewController
- (IBAction)button1Tapped:(id)sender {
SecondViewController *secondViewController = [[SecondViewController alloc] init];
secondViewController.title = #"View2";
[self.navigationController pushViewController:secondViewController animated:YES];
}
#implementation SecondViewController
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
ThirdViewController *thirdViewController = [[ThirdViewController alloc] init];
thirdViewController.title = #"View3";
if (indexPath.row == 0) {
[self.navigationController pushViewController:thirdViewController animated:YES];
[secondViewTableView deselectRowAtIndexPath:indexPath animated:YES];
}
}
So, I have questions:
Where should I create the next view? In my code view has created in "previous" class: view2 created in FirstViewController, view3 created in SecondViewController etc. All new ViewControllers are inside the method that initiates the navigation, is it right way? I think it's wrong, but the navigation is working.
Problems with headers in the navigation bar. It turns out that the title of view2 is only displayed when moving from view1 to view2, but when going back from view3 to view2 – header disappears. I googled, tried to add self.title = #"name" to viewDidLoad, initWithNibName, viewWillAppear – none of this works.
So I've solved the problem with disappearing title of navigation bar. The problem was in my custom back button: self.navigationItem.title = #"";
It was working and title "Back" from my back button disappeared but also title of navigation bar disappeared too. The right way to make back button untitled is:
UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithTitle:#"" style:UIBarButtonItemStyleBordered target:nil action:nil];
[self.navigationItem setBackBarButtonItem:backButton];
The problem is pretty simple to understand with pictures.
I have a UINavigationController that allow the user to switch between to views.
The first view contains a search bar and a table view like so :
The second is a basic view where information about the cell are display
When I click on the search bar, the navigation controller gets hidden and the search bar is now at the top.
Now, if I click on a cell, it goes to the second views, but the navigation bar is first hidden like below :
And then, it automatically appears like that :
I have tried a couple of things like show the navigation bar before pushing the next view controller but it is quite ugly..
Does anyone know how to have the show the navigation bar directly on the second view (like in the contact application)?
[UPDATE] : Code
AppDelegate.m (I'm talking about navigationcontroller2)
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
FirstViewController *viewController1 = [[FirstViewController alloc] initWithNibName:#"FirstViewController" bundle:nil];
SecondViewController *viewController2 = [[SecondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
viewController1.managedObjectContext = [self managedObjectContext];
viewController2.managedObjectContext = [self managedObjectContext];
viewController1.viewController2 = viewController2;
UINavigationController *navigationcontroller1 = [[UINavigationController alloc] initWithRootViewController:viewController1];
[navigationcontroller1.navigationBar setTintColor:[UIColor lightGrayColor]];
UINavigationController *navigationcontroller2 = [[UINavigationController alloc] initWithRootViewController:viewController2];
[navigationcontroller2.navigationBar setTintColor:[UIColor lightGrayColor]];
self.tabBarController = [[UITabBarController alloc] init];
self.tabBarController.viewControllers = [NSArray arrayWithObjects:navigationcontroller1, navigationcontroller2, nil];
self.window.rootViewController = self.tabBarController;
[self.window makeKeyAndVisible];
return YES;
}
FirstView.m
- (void) searchBarTextDidBeginEditing:(UISearchBar *)theSearchBar {
[self.navigationController setNavigationBarHidden:YES animated:YES];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if (!noResultsToDisplay) {
PinDetailsViewController *pinDetailsViewController = [[PinDetailsViewController alloc] initWithNibName:#"PinDetailsViewController" bundle:nil];
NSManagedObject *managedObject = [fetchedResultsController objectAtIndexPath:indexPath];
Pin *pin = (Pin *) managedObject;
[self.navigationItem setTitle:#"Pins"];
[self.navigationController pushViewController:pinDetailsViewController animated:YES];
[pinDetailsViewController updateWithPin:pin];
}
}
If you need anything else, just ask but I think it's all there.
Try to use this code in each viewcontroller.
- (void) viewWillAppear:(BOOL)animated
{
[self.navigationController setNavigationBarHidden:NO animated:animated];
}
- (void) viewWillDisappear:(BOOL)animated
{
[self.navigationController setNavigationBarHidden:YES animated:animated];
}
Before you push the new view controller, you should unhide the navigation bar:
[self.navigationController setNavigationBarHidden:NO animated:YES];
I had a similar problem with the position of my navbar. Mine was moving up behind the status bar, and I fixed the issue by manually setting the navbar frame:
-(void)adjustNavBarOrigin
{
CGRect r = self.navigationController.navigationBar.frame;
r.origin = CGPointMake(0, 20); // 20 is the height of the status bar
self.navigationController.navigationBar.frame = r;
}
I had to call this method in a number of places, including viewWillAppear: and didRotateFromInterfaceOrientation:, but it worked a treat :)
Hiding the UINavigationBar can disturb the properties sometimes. Try using the property alpha instead of hidden.
I am working on a small app, according to the requirement the app should have a tabBarItem with 3 items. For this I have programmatically created the tabBarController in the AppDelegate.m file and added the 3 different viewControllers, instantiated them and everything is working good. I see the tabBarItems and all views are working. In one of the views lets say in SecondViewController I show a popOverController where I used a UITableView and populate it with items. When I click one of the items it should show another view lets say sendFeedback. Until there everything is working fine, but as soon as this sendFeedback is presented as the modal view, it occupies the whole app i.e it hides the tabBarItem.
I present the important pieces of code here for review:
AppDelegate.m
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
// Override point for customization after application launch.
UIViewController *viewController1 = [[FirstViewController alloc] initWithNibName:#"FirstViewController" bundle:nil];
viewController1.title = #"First";
UIViewController *viewController2 = [[SecondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
viewController2.title = #"Second";
UITableViewController *tableView3 = [[tableViewController alloc]initWithNibName:#"tableViewController" bundle:nil];
tableView3.title = #"Third";
self.tabBarController = [[UITabBarController alloc] init];
self.tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2, tableView3 ,nil];
self.tabBarController.delegate = self;
self.window.rootViewController = self.tabBarController;
[self.window makeKeyAndVisible];
[viewController1 release];
[viewController2 release];
[tableView3 release];
return YES;
}
In my popOverViewController.m file I am checking which row is selected in the table according to that I present the view
#pragma mark - TableView Delegate Methods
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
sendFeedback *sendEmailViewController = [[sendFeedback alloc]initWithNibName:#"sendFeedback" bundle:nil];
downLoad *downloadFilelViewController = [[downLoad alloc]initWithNibName:#"downLoad" bundle:nil];
if (indexPath.row == 0)
[self presentModalViewController:sendEmailViewController animated:YES];
else
[self presentModalViewController:downloadFilelViewController animated:YES];
}
Can anyone guide me how to overcome this with the multiple views. In case if anyone requires more information from my side I would be glad to provide.
NOTE: It is the same with the other view (downLoad) as well
EDIT: Here is how I am initializing my PopOverController in the AppDelegate.m file
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
if([viewController isKindOfClass:[SecondViewController class]]){
NSInteger index = [[self tabBarController] selectedIndex];
CGRect buttonFrame = [[[[[self tabBarController] tabBar] subviews] objectAtIndex:index+1] frame];
PopOverViewController *popoverView = [PopOverViewController new];
popoverView.contentSizeForViewInPopover = CGSizeMake(250, 85);
popover = [[UIPopoverController alloc]initWithContentViewController:popoverView];
NSLog(#"X:%f Y:%f",buttonFrame.origin.x,buttonFrame.origin.y);
[popover presentPopoverFromRect:buttonFrame inView:self.tabBarController.tabBar permittedArrowDirections:UIPopoverArrowDirectionDown animated:YES];
}
Thanks
Modal view controllers are used to "block" your application and fulfill a task before you can proceed. So modal view controllers are not what you want to use.
Instead wrap your controllers which have to be shown in the popover in a navigation controller. In the tableView:didSelectRowAtIndexPath: method you can push the corresponding view controller to the navigation stack.
To slove your problem:
At the place where you create the popovercontroller initialize it with a new UINavigationController. And the navigation controller you have to initialize with a rootviewcontroller namely PopOverViewController.m.
PopOverController *popoverContentController = [[PopOverController alloc] init];
UINavigationController *navcon = [[UINavigationController alloc] initWithRootViewController:popoverContentController];
popoverController = [[UIPopoverController alloc] initWithContentViewController:popoverContentController];
And in PopOverController.m
if (indexPath.row == 0)
[self.navigationController pushViewController:sendEmailViewController animated:YES];
else
[self.navigationController pushViewController:downloadFilelViewController animated:YES];
I created a new window based application, and a RootViewController that sublcasses UIViewController. I created a UINavigationController in the AppDelegate and when I add the UINavigationController's view to the window, I do see the navigation bar on top. However, I cannot seem to add a button to the navigation bar - there are no compile errors, but the button (and the title) does not show up. The code is below:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
RootViewController * rootViewController = [[RootViewController alloc] initWithNibName:#"RootViewController" bundle:nil];
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:rootViewController];
UIBarButtonItem *next = [[UIBarButtonItem alloc] initWithTitle:#"Next" style:UIBarButtonItemStyleDone target:nil action:nil];
navigationController.title = #"Foo";
navigationController.navigationItem.rightBarButtonItem = next;
[self.window addSubview:navigationController.view];
// Override point for customization after application launch.
[self.window makeKeyAndVisible];
return YES;
}
What am I doing wrong?
Change this:
navigationController.navigationItem.rightBarButtonItem = next;
to this:
rootViewController.navigationItem.rightBarButtonItem = next;
May be style:UIBarButtonItemStyleDone only used in editing mode is YES. If in Root controller or sub view controller, you may try call self.editing = YES, but in AppDelegate you can't.
How can I trigger the navigationController:willShowViewController delegate method for my implementation below so that all the view controllers in the navigation controller will conform to the colorWithHexString #faf6f5?
Currently, my FirstViewController will be displayed but it doesn't seem to call the delegate method to change the color of it's navigation bar (as well as for all other view controllers that are stacked onto the navigation controller subsequently). Note that I have already added the "UINavigationControllerDelegate" to my app delegate header file.
//In App Delegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
//Set First View
FirstViewController *firstView = [[FirstViewController alloc]init];
// pushes a nav con
UINavigationController *tempNavcon = [[UINavigationController alloc]initWithRootViewController:firstView];
self.navcon = tempNavcon;
[self.window addSubview:navcon.view];
}
- (void)navigationController:(UINavigationController *)navigationController
willShowViewController:(UIViewController *)viewController animated:(BOOL)animated{
navigationController.navigationBar.tintColor = [UIColor colorWithHexString:#"#faf6f5"];
}
is there a reason why you are trying to change the tintColor in an event method rather than when the UINavigationBar instance is created?
Here's how you do it. (Note that UIColor doesn't accept hex values; you should use an RGB value, or check this page.
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
//Initialize your view controller.
FirstViewController * firstView = [[FirstViewController alloc] init];
// Create an instance of a UINavigationController. Its stack contains only firstView.
UINavigationController *navController = [[UINavigationController alloc]
initWithRootViewController:firstView];
//Here is where you set the color of the navigationBar. See my note above for using RGB.
navController.navigationBar.tintColor = [UIColor greenColor];
// You can now release the firstView here, navController will retain it
[firstView release];
// Place navigation controller's view in the window hierarchy
[[self window] setRootViewController:navController];
[navController release];
[self.window makeKeyAndVisible];
return YES;
}