I have a navigation view controller that pushes "viewController1" properly. Then, from "viewController1", goToApp function is called in order to push "appViewController". Function goToApp is executed but aplication remains at same view, "viewControlller1". How to push it? Thank you.
from viewController1:
navigationViewController *theInstance = [[navigationViewController alloc] init];
[theInstance goToApp];
in navigationViewController:
-(void)goToApp {
appViewController *AppsViewController = [[appViewController alloc] initWithNibName:#"appViewController" bundle:nil];
[[self navController] pushViewController:AppsViewController animated:YES];
[AppsViewController release];
}
goToApp executed but appViewController not launched.
You should not create a new UINavigationController in viewController1. You should get it through the property navigationController. That property will return the UINavigationController that has the UIViewController on it's stack (if any, so it can be nil).
UINavigationController * theInstance = self.navigationController;
[theInstance goToApp];
See: http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIViewController_Class/Reference/Reference.html property navigationController.
Besides that, it is a better convention to name your pointers correctly to what they represent. I would suggest to rename theInstance to currentNavigationController or just navigationController.
Related
I don't know if what I'm trying to do is possible, but because I haven't the desired results, I guess not.
What I'm trying and need to do is to call a SplitViewController from a previous ViewController, using presentViewController.
I know, SplitViewController have to be the rootViewController, but I need to explore the most possible options to achieve what I need to do.
I have a MainMenu with buttons, and with every button, I need to call a SplitViewController. First, how can do this?
What I'm trying to do is this:
First, in AppDelegate I'm calling the MainMenu, and add as a subview and other things:
-(BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
[window addSubview:self.mainMenu.view];
[self.mainMenu presentModalViewController:self.firstMenu animated:NO];
[self.window makeKeyAndVisible];
return YES;
}
Then, in the MainMenu, I'm calling SecondViewController, in modal view, using this code:
SecondViewController *secV = [[SecondViewController alloc]initWithNibName:#"SecondViewController" bundle:nil];
secV.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:secV animated:YES];
In this SecondViewController, I'm creating SplitViewController, with Master & DetailViewController's, using this code:
-(void)viewDidLoad{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
UISplitViewController *splitViewController = [[UISplitViewController alloc]init];
SecondMenuViewController *secMenu = [[SecondMenuViewController alloc]init];
UINavigationController *navLef = [[UINavigationController alloc]init];
[navLef pushViewController:secMenu animated:NO];
SecondMainViewController *secMain = [[SecondMainViewController alloc]init];
UINavigationController *navRig = [[UINavigationController alloc]init];
[navRig pushViewController:secMain animated:NO];
splitViewController.delegate = secMain;
splitViewController.viewControllers = [NSArray arrayWithObjects:navLef, navRig, nil];
MainAppDelegate *mainApp = [[MainAppDelegate alloc]init];
[mainApp changeRootViewController:splitViewController];
navRig = nil;
navLef = nil;
secMain = nil;
secMenu = nil;
splitViewController = nil;
}
As you can see, I'm calling a method in MainAppDelegate, to change view and RootViewController, because SplitViewController have to be RootViewController. This is the method:
-(void)changeRootViewController:(UISplitViewController *)splitViewController{
[self.window addSubview:splitViewController.view];
self.window.rootViewController = splitViewController;
}
I know, this looks like a mess. And when I run, the SplitViewController never shows, so I assume, what I'm trying to do is not possible? Or In what I'm wrong?
If it is everything, what can I do to show a SplitViewController after my MainViewController?
I'm using XCode4.4 and iOS5
Thank you very much
A better way would be to make your UISplitViewController the root view controller in application:didFinishLaunchingWithOptions:. Then present your MainMenu on top of it. You can change the subviews displayed by the split view controller to correspond to what button the user pushes in your MainMenu.
First, didFinishLaunchingWithOptions: is too early to be calling presentModalViewController. You haven't even got an interface yet!
Second, you don't seem to have a root view controller (although perhaps you're getting one from a nib? you should probably stop doing that; use the techniques shown in the current application templates).
Third, note that now that we have custom container views, there is no need for you to use UISplitViewController at all; you can construct your own view / view controller hierarchy, and you might be happier doing so, since UISplitViewController is not a very well-constructed class.
I would like to know what kind of trick to use for "not pushing" a view controller into the navigation controller stack (iOS)
I have this :
If user is not logged, show view A then show B
If user is logged, show B
As I am using the storyboard, I used a performSegue if the user is logged so he goes directly to B. But with this method, the Navigation Controller gets a push of view A in the stack.
I was thinking of poping out a level of the stack in some void (but I don't know how to do this).
I was also thinking of not pushing the view into the nav controller stack (but I don't know how to do this).
Thanks
Update :
I tried this :
//The view B
TabBarMain* mainViewController = [[TabBarMain alloc] init];
//If already logged in
if([username length] == 0)
{
NSArray *viewControllers = [NSArray arrayWithObject:mainViewController];
[self.navigationController setViewControllers:viewControllers animated:NO];
}
The problem of this code is that it shows me a black screen (doesn't crash). It seems that I need to init something and I have nothing in my TabBarMain.m, I don't know what to write in there. This TabBarMain is linked to the Tab Bar Controller of the Storyboard.
Is there no other way ?
Try this on for size in your rootViewController's viewDidLoad.
- (void)viewDidLoad
{
NSArray *viewControllers
if (logged) {
NSArray *viewControllers = [NSArray arrayWithObject:viewControllerB];
} else {
NSArray *viewControllers = [NSArray arrayWithObject:viewControllerA];
}
[self.navigationController setViewControllers:viewControllers animated:NO];
}
Since your viewController is linked in Storyboard and not instantiated in code you need to instantiate it from the storyboard not your empty code. Make sure the identifier matches the identifier for your ViewController in your storyboard.
TabBarMain *mainViewController = [[UIStoryboard storyboardWithName:#"MainStoryboard" bundle:NULL] instantiateViewControllerWithIdentifier:#"tabBarMain"];
I have MainMenuViewController with button which action is
- (IBAction) goToFirstView {
FirstViewController *fvc = [[FirstViewController alloc] init];
[self.view addSubview:fvc.view];
[fvc release];
}
FirstViewController have UIButton with action
- (IBAction) rightArrow {
SecondViewController *svc = [[SecondViewController alloc] init];
[self.view addSubview:svc.view];
[svc release];
}
But when I press "rightArrow" button app crashes with "EXC_BAD_ACCESS". Can't found my problem. Help me please.
[svc release];
The problem is here. When releasing the view controller, the view's events will target a freed object, and make your program crash (probably in viewDidLoad or viewDidAppear if it's instant but it doesn't matter). Note that a view does not (normally, AFAIK) retain it's view controller, if that might have been your assumption...
When you say [self.view addSubview:svc.view] you're adding SecondViewController's view to FirstViewController's view. Similar with MainViewController and FirstViewController. What you'll end up with is a view hierarchy that looks like this:
main view
first view
second view
I doubt that's really what you want. Instead, use a navigation controller with your MainViewController as the nav controller's root controller, and then use -pushViewController:animated: to push the controllers (not the views!) onto the navigation stack.
The following code should work, right?
ViewController2 *childView = [[ViewController2 alloc] initWithNibName:#"ViewController2" bundle:nil];
[self.navigationController pushViewController:childView animated:YES];
[childView release];
It doesn't do anything though. There are no error messages. The view just doesn't get switched. viewDidLoad does not even execute inside ViewController2.
That code won't do anything if the view controller presenting it doesn't have a navigation controller, i.e. it isn't in a navigation controller stack. In that case, you'll be calling a method (pushViewController:animated:) on a nil object (self.navigationController) which does nothing. Thus, you can only use this this method if the "parent" view controller is in a UINavigationController stack.
Use this:
[self presentModalViewController:viewControllerNameHere animated:YES];
I am creating my Nav and TabBar in code at launch via:
IN : myAppDelegate.m
- (void)applicationDidFinishLaunching:(UIApplication *)application {
// set up a local nav controller which we will reuse for each view controller
UINavigationController *localNavigationController;
// create tab bar controller and array to hold the view controllers
tabBarController = [[UITabBarController alloc] init];
NSMutableArray *localControllersArray = [[NSMutableArray alloc] initWithCapacity:4];
// setup the first view controller (Root view controller)
RootViewController *myViewController;
myViewController = [[RootViewController alloc] initWithTabBar];
// create the nav controller and add the root view controller as its first view
localNavigationController = [[UINavigationController alloc] initWithRootViewController:myViewController];
// add the new nav controller (with the root view controller inside it)
// to the array of controllers
[localControllersArray addObject:localNavigationController];
// release since we are done with this for now
[localNavigationController release];
[myViewController release];
// setup the first view controller just like the first
ResortsListViewController *resortsListViewController;
resortsListViewController = [[ResortsListViewController alloc] initWithNibName:#"ResortsListView" bundle:nil];
resortsListViewController.title = #"Category1";
resortsListViewController.tabBarItem.image = [UIImage imageNamed:#"image1.png"];
resortsListViewController.navigationItem.title=#"Category1";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:resortsListViewController];
[localControllersArray addObject:localNavigationController];
[localNavigationController release];
// setup the second view controller just like the first
ResortsListViewController *resortsListViewController;
resortsListViewController = [[ResortsListViewController alloc] initWithNibName:#"ResortsListView" bundle:nil];
resortsListViewController.title = #"Category2";
resortsListViewController.tabBarItem.image = [UIImage imageNamed:#"image2.png"];
resortsListViewController.navigationItem.title=#"Category2";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:resortsListViewController];
[localControllersArray addObject:localNavigationController];
[localNavigationController release];
// setup the third view controller just like the first
ResortsListViewController *resortsListViewController;
resortsListViewController = [[ResortsListViewController alloc] initWithNibName:#"ResortsListView" bundle:nil];
resortsListViewController.title = #"Category3";
resortsListViewController.tabBarItem.image = [UIImage imageNamed:#"image3.png"];
resortsListViewController.navigationItem.title=#"Category3";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:resortsListViewController];
[localControllersArray addObject:localNavigationController];
[localNavigationController release];
[resortsListViewController release];
// load up our tab bar controller with the view controllers
tabBarController.viewControllers = localControllersArray;
// release the array because the tab bar controller now has it
[localControllersArray release];
// add the tabBarController as a subview in the window
[window addSubview:tabBarController.view];
// need this last line to display the window (and tab bar controller)
[window makeKeyAndVisible];
}
As you see, I am re-using ResortsListViewController for different category displays (resorts with Beaches, resorts with Pools, resorts with espresso bars) ... now, without harassing me (grin) about the silliness of my categories (cos this is a test app) I need need to do several things:
I need to be able to know which tab click caused the ResortsListViewController to be displayed. I was hoping to use TAG but "initWithRootViewController" does not have the "tag" control. So, if i use an imagefilename that is the category name, I can use that filename to distinguish categories...or even navigationItem name. I need to know if there is a way for ResortsListViewController to know which tabbar item click caused it's display. I thought to look for a "action" that I could assign to the tabbar item, but that is not the way tabbarcontroller works.
When clicking from one tab to another, the view does indeed change, the title of ResortsListViewController changes, etc...but the TABLEVIEW it holds does not clear and display any new data. Searching the web I have found a possible solution:
http://discussions.apple.com/thread.jspa?threadID=1529769&tstart=0
basically saying:
In order for UINavigationControllers
to send
"viewWill/Did/Appear/Disappear"
messages, it needs to have received
"viewWill/Did/Appear/Disappear" from
its container.
What is the container for my UINavigationControllers in this situation? myAppDelegate is defined in the .h file as:
NSObject <UIApplicationDelegate, CLLocationManagerDelegate>
and does not have a:
- (void)viewWillAppear:(BOOL)animated {
}
section. When I add one it says "NSObject may not respond to -viewWillAppear" in the debugger.
Any help out there?
1) This is fairly simple. You need to set the delegate property for the UITabBarController. You would set this to the controller object that owns your tabbarcontroller (or your app delegate if that is your setup). Whichever object is set as the delegate would then receive:
- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController
AND
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
to manage tab selections. Place one of these methods in the implementation of whatever object you set as the delegate (you would want it to be the object that owns all of the controllers).
2) If you have a UIViewController that appears as a tab selection (such as ResortsListViewController) then you would need to put the viewWillAppear method in the controller implementation yourself:
#implementation ResortsListViewController
- (id)initWithNibName:(NSString *)name bundle:(NSBundle *)bundle {
...
}
... etc. ....
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[table reloadData];
}
...
#end
Let me know if I misunderstood the second part of your question.
Okay, here goes: This is the correct answer to the question, however, it did not end up being this hard. All I had to do was the following:
Create a property in ResortViewController of type int with variable name whichChoice (for instance). Then address it in the setup of the TabBarController a la:
// setup the first view controller just like the first
ResortsListViewController *resortsListViewController;
resortsListViewController = [[ResortsListViewController alloc] initWithNibName:#"ResortsListView" bundle:nil];
// START HERE IS THE CHANGE
resortsListViewController.whichChoice = 1;
// END HERE IS THE CHANGE
resortsListViewController.title = #"Category1";
resortsListViewController.tabBarItem.image = [UIImage imageNamed:#"image1.png"];
resortsListViewController.navigationItem.title=#"Category1";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:resortsListViewController];
[localControllersArray addObject:localNavigationController];
[localNavigationController release];
To find out which tab was clicked when my resortsListViewController takes over, I simply query the class variable: whichChoice to get the answer.
Things like this are so simple you skip over them. I thought you had to pass the variable in an action and specify where it would go with the target like you do in other objects -- but when you set things up ahead of time you do not have to do that. Now, having said that, dynamically setting "whichChoice" is not so easy without a lot more thought...but setting it to a variable KNOWN at setup is fine.
For answer #2, I simply put a variable style of IBOutlet in my class, hooked it up to the table, and then followed your instructions, because without the variable in the IBOutlet and hooking it up to the table, there is no reference to the table view. For some reason hooking up the table simply to the VIEW "Referencing Outlet" and calling [self.tableview reloadData] did not do the job.
But for the most part, your answers were right and led me in the right direction. As an aside, I really hate that you have to right-click and drag from here-to-there in IB if you have an IB element you built. You should be able to hook it up in code using it's ObjectId (or something). That would be more in line with programmers. I know IB is made to allow programming to be easier for designers, but gee wilikers..it is hard to wrap my mind around! I end up dropping IB and creating elements in code most of time time...which I do not know if is as fast to execute. I tend to think not...but have no proof to the contrary.