In App Delegate do I:
need to release my "window" and "navigationController"? and
where abouts should I release it out of (a) applicationDidReceiveMemoryWarning and (b) dealloc?
Code Listing
#interface weekendviewerAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
UINavigationController *navigationController;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet UINavigationController *navigationController;
#implementation weekendviewerAppDelegate
#synthesize window;
#synthesize navigationController;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
RootViewController *rootViewController = (RootViewController *)[navigationController topViewController];
rootViewController.managedObjectContext = self.managedObjectContext;
self.window.rootViewController = self.navigationController;
// Configure and show the window
[window addSubview:[navigationController view]];
[window makeKeyAndVisible];
return YES;
}
.
.
As Bolt clock commented you need to add a dealloc method in appDelegate class.
- (void)dealloc {
[navigationController release];
[window release];
[super dealloc];
}
Well #greg if you ever release your window or navigationController in applicationDidReceiveMemoryWarning dont u think your application will crash when ur application receives memory warning.
As #Bolt and #ishu said you need to release it in dealloc methods only.
Also in applicationDidReceiveMemoryWarning method you can release those class variables which are not going to be used after some point of time, as releasing them may cause your app to crash.
So choose wisely what variables are not important that might cause your application to crash or stop your app from working properly.
Related
Basically, I have two view controllers inside the MainWindow.xib that can be viewed by clicking the Bar Button in my Navigation Controller. I wanted those two view controllers to be separated from the MainWindow.xib with their own header, implementation and xib files and still make Navigation Controller inside of MainWindow.xib work in them.
To better understand it, please see the codes below:
Thanks a lot!
TestAppDelegate.h
#import <UIKit/UIKit.h>
#interface TestAppDelegate : NSObject <UIApplicationDelegate>
{
//Navigation Controller
IBOutlet UINavigationController *navigationController;
//View Controllers
UIViewController *viewController;
UIViewController *viewController2;
UIViewController *viewController3;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
//Navigation Controller
#property (nonatomic, retain) IBOutlet UINavigationController *navigationController;
//View Controllers
#property (nonatomic, retain) IBOutlet UIViewController *viewController;
#property (nonatomic, retain) IBOutlet UIViewController *viewController2;
#property (nonatomic, retain) IBOutlet UIViewController *viewController3;
- (IBAction)next;
- (IBAction)next2;
#end
TestAppDelegate.m
#import "TestAppDelegate.h"
#implementation TestAppDelegate
#synthesize window = _window;
//Navigation Controller
#synthesize navigationController;
//View Controllers
#synthesize viewController;
#synthesize viewController2;
#synthesize viewController3;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// Override point for customization after application launch.
//Navigation Controller
[self.window addSubview:[navigationController view]];
[self.window makeKeyAndVisible];
return YES;
}
- (void)applicationWillResignActive:(UIApplication *)application
{
}
- (void)applicationDidEnterBackground:(UIApplication *)application
{
}
- (void)applicationWillEnterForeground:(UIApplication *)application
{
}
- (void)applicationDidBecomeActive:(UIApplication *)application
{
}
- (void)applicationWillTerminate:(UIApplication *)application
{
}
- (void)dealloc
{
[viewController release];
[viewController2 release];
[viewController3 release];
[navigationController release];
[_window release];
[super dealloc];
}
- (IBAction)next {
[navigationController pushViewController:viewController2 animated:YES];
}
- (IBAction)next2 {
[navigationController pushViewController:viewController3 animated:YES];
}
#end
Inside MainWindow.xib:
http://i52.tinypic.com/10xa45f.png
I normally don't touch MainWindow.xib. I suggest the following:
Create a MainController which will be your MainView that subclass UIViewController by going to File > New > New File. That will create a .h/.m and nib file for each ViewController. There add whatever UI you want for your app. For Example, add two buttons and wire those buttons to IBActions in your MainController. This should be declared and implemented in your MainController.{h/m}, respectively.
After that create another two ViewControllers, the same way.
The body of those IBActions should create an instance of the your ViewControllers and then push them.
It would look something like this:
YourViewController *yvc = [[YourViewController alloc] init];
[self.navigationController pushViewController:yvc animated:YES];
[yvc release];
Finally, you have to push the MainController in your AppDelegate and add your NavigationController to the view.
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
MainViewController *mvc = [[MainViewController alloc] init];
UINavigationController *unvc = [[UINavigationController alloc] init];
[unvc pushViewController:mvc animated:NO];
[mvc release];
[self.window addSubview:unvc.view];
[self.window makeKeyAndVisible];
return YES;
}
Set the "class" property in Interface Builder (third tab in the inspector, "Custom Class") to the name of the custom class you're planning to use, and then put the name of the .xib file you want to load from in the "NIB Name" (fourth tab).
The code you're using to push the viewController is alright. Make sure to never accidentaly dealloc any of the two UIViewController.
Speaking of which, keep in mind that this approach is keeping the ViewControllers always in memory, even when not in use. Another approach is to completely remove the IBOutlets for the two ViewControllers, and do something like:
- (IBAction)next
{
MyCustomViewController *customViewController = [[MyCustomViewController alloc] initWithNibName:<#NibName or nil#> bundle:[NSBundle mainBundle]];
[navigationController pushViewController:customViewController animated:YES];
[customViewController release];
}
This creates the object when needed (If I remember right, the UI elements from the xib are cached somewhere, so that may be irrelevant[citation needed]). Just something to keep in mind, depending on the frequency of use of your two ViewControllers.
When my app first starts, it shows a main page to log in to Facebook. Then, it goes to the UITabBarController. The code that I have in my app delegate is the following:
//this is the .h
#interface NMeAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
MainViewController *controller;
UITabBarController *tabBar;
}
#property (nonatomic, retain) IBOutlet UITabBarController *tabBar;
#property (nonatomic, retain) MainViewController *controller;
#property (nonatomic, retain) IBOutlet UIWindow *window;
#end
//this is the .m of the app delegate
#import "NMeAppDelegate.h"
#implementation NMeAppDelegate
#synthesize window;
#synthesize tabBar;
#synthesize controller;
#pragma mark -
#pragma mark Application lifecycle
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
controller = [[MainViewController alloc] init];
[window addSubview:tabBar.view];
[window addSubview:controller.view];
[window makeKeyAndVisible];
return YES;
}
Inside of MainViewController, I actually have a UserInfo object, which has all of the information that I need for the UITabBarController. The problem is that after getting this info in the UITabViewController, how do I pass this UserInfo to the UITabBarController` or possible the ViewController that is inside the UITabBarController so they were able to access this UserInfo? How to do this?
I hope my question makes sense.
you need to have an instance of your UserInfo object available to the tab bar controller. probably pass it into a instance variable of type UserInfo in your UItabBarController/each view controller whenever you transition into the specified controller.
edit: you should really have this passed into the view Controller it needs to be in (since it doesn't appear you have a custom UITabBarController subclass), or you could use a shared UserInfo variable in your app delegate to keep up with the information.
But as the commenter said, the question is not very clear at all and i could be completely misunderstanding what you want to do.
Hope that helps.
I have the following code in my AppDelegate.h file:
#class mainViewController;
#class AboutViewController;
#interface iSearchAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
mainViewController *viewController;
AboutViewController *aboutController;
UINavigationController *nav;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet mainViewController *viewController;
#property (nonatomic, retain) IBOutlet AboutViewController *aboutController;
#property (nonatomic, retain) IBOutlet UINavigationController *nav;
[...IBActions declared here...]
#end
Then, in my .m file:
#implementation iSearchAppDelegate
#synthesize window;
#synthesize viewController, aboutController, settingsData, nav, engines;
- (void)applicationDidFinishLaunching:(UIApplication *)application {
[window addSubview:nav.view];
[window addSubview:aboutController.view];
[window addSubview:viewController.view];
[window makeKeyAndVisible];
}
-(IBAction)switchToHome{
[window bringSubviewToFront:viewController.view];
}
-(IBAction)switchToSettings{
[window bringSubviewToFront:nav.view];
}
-(IBAction)switchToAbout{
[window bringSubviewToFront:aboutController.view];
}
- (void)dealloc {
[viewController release];
[aboutController release];
[nav release];
[window release];
[super dealloc];
}
#end
Somehow, when I run the app, the main view presents itself fine... however, when I try to execute the actions to switch views, the app crashes with an EXC_BAD_ACCESS.
So, I think it has something to do with memory management, but I'm not quite sure.
Thanks for any help in advance.
Link to screenshots of code is here: link...
SOLVED: I fixed the issue by taking out the IBActions and making them into regular methods... apparently, XCode doesn't like it when you put IBActions in an AppDelegate.
... message sent to deallocated instance ...
If it is memory management, my first step would be to enable NSZombie and discover what was being messaged after being dealloc'ed. Two obvious things I can think of:
Uninitialised property/variable.
De-allocated (non-retained) property
Have your controls in interface builder been connected to the IBActions?
Somewhere in your code, you are invoking [iSearchAppDelegate performSelector:withObject:withObject:]. You haven't shown that code here but that's likely where the problem is.
I am creating a viewController programmatically (hopefully the right way) My problem is that I previously created the controller in IB and have code I want to call in awakeFromNib. As I currently have things viewDidLoad works fine but awakeFromNib does not. Is there anyway to get awakeFromNib to call or an alternative method that I can use in its place?
#class MyViewController;
#interface TEST_ControllerAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
MyViewController *viewController;
}
#property(nonatomic, retain) IBOutlet UIWindow *window;
#end
.
#implementation TEST_ControllerAppDelegate
#synthesize window;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
viewController = [[MyViewController alloc] init];
[window addSubview:[viewController view]];
[window makeKeyAndVisible];
return YES;
}
- (void)dealloc {
[viewController release];
[window release];
[super dealloc];
}
#end
EDIT_001:
I have pretty much come to the conclusion that using viewDidLoad is going to be my best option, particularly as I want to initialise IBOutlet instance variables.
In order to be called, the awakeFromNib method must be parameter-less (no sender):
- (void)awakeFromNib {
// Do whatever is needed...
}
Take care of the casing, as no error or warning will be logged if you mistype the method.
This is my first iPhone application and it's based on a top-level tableview. Selections of rows either go to another tableview or to a view. The application runs OK on the simulator but when ported to my iPhone it fails with a EXC_BAD_ACCESS error. This happens while my splash screen is being displayed. NSLog indicates that the program processes in appDelegate.m:
[window addSubview:[navigationController view]];
[window makeKeyAndVisible];
but then it just fails. The code never seems to reach the viewDidLoad in my RootViewController.
I'm sure that I've got the RootViewController and appDelegates mixed up somehow but cannot figure out exactly what's wrong. I've attached the beginning code of my RootViewController, appDelegate - any help appreciated.
RootViewController.h code....
#interface RootViewController : UITableViewController {
TyresViewController *tyresController;
EngineSpecViewController *engineSpecController;
CarbonTaxBandViewController *carbonTaxBandController;
TyreSpecificationsViewController *tyreSpecificationsController;
FuelConsumptionandEmissionsViewController *fuelConsumptionandEmissionsController;
CompanyCarTaxBandViewController *companyCarTaxBandController;
CarbonCalculatorViewController *carbonCalculatorController;
ReminderViewController *reminderController;
//NSString *selectedSpecification;
NSArray *listOfItems;
}
RootViewController.m code ......
#import "RootViewController.h"
#implementation RootViewController
#synthesize listOfItems;
//#synthesize selectedSpecification;
#synthesize carbonTaxBandController;
#synthesize engineSpecController;
#synthesize tyreSpecificationsController;
#synthesize tyresController;
#synthesize fuelConsumptionandEmissionsController;
#synthesize companyCarTaxBandController;
#synthesize carbonCalculatorController;
#synthesize reminderController;
appDelegate.h code.....
#interface MyCar3AppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
UINavigationController *navigationController;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
#property (nonatomic, retain) IBOutlet UINavigationController *navigationController;
#end
appDelegate.m code .....
- (void)applicationDidFinishLaunching:(UIApplication *)application {
// Override point for customization after app launch
[window addSubview:[navigationController view]];
[window makeKeyAndVisible];
}
Just a thought, in your main Info.plist file there should be an entry for Main nib file base name. This refers to the nib that will be loaded when your app starts. The simulator is not case sensitive, but the device is. Check the case of the value of your main nib.