How to load and unload a UIViewController from the window - ios

Question

I have create some logic when the app is loaded that I can load from 3 different views depending on some values I set in my plist.
This is what my code looks like
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
//sets context for coredata
CoreDataController *coreDataController = [CoreDataController sharedManager];
coreDataController.managedObjectContext = self.managedObjectContext;
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
PrefsController *prefsController = [[PrefsController alloc] init];
NSDictionary *prefsDictionary = [prefsController readPrefs];
NSLog(#"%#", prefsDictionary);
NSString *projectListBoolString = [prefsDictionary objectForKey:#"ProjectListAvailable"];
NSString *installsBoolString = [prefsDictionary objectForKey:#"InstallsAvailable"];
NSString *finishinBoolString = [prefsDictionary objectForKey:#"FinishingAvailable"];
if (([projectListBoolString isEqualToString:#"T"]) && ([installsBoolString isEqualToString:#"F"]) && ([finishinBoolString isEqualToString:#"F"])) {
self.getProjectListViewController = [[GetProjectListViewController alloc] initWithNibName:#"GetProjectListViewController" bundle:nil];
self.window.rootViewController = self.getProjectListViewController;
[self.window makeKeyAndVisible];
}
else if (([projectListBoolString isEqualToString:#"T"]) && ([installsBoolString isEqualToString:#"T"]) && ([finishinBoolString isEqualToString:#"T"])) {
self.currentProjectListViewController = [[CurrentProjectListViewController alloc] initWithNibName:#"CurrentProjectListViewController" bundle:nil];
self.window.rootViewController = self.currentProjectListViewController;
[self.window makeKeyAndVisible];
}
else {
self.viewController = [[ViewController alloc] initWithNibName:#"ViewController" bundle:nil];
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
}
return YES;
}
I would like to be able to then load and unload UIViewControllers (including removing from memory by using buttons presses etc.
I dont want to use a navigaiton based controller as I want the views to be static or individual if that makes more sense.
If someone could show me some example code to load a new UIViewController to the window and remove the old UIViewController that would be greatly apprecaited.
However I am not sure of the correct was to handle this, or even how the code looks.
any help would be greatly appreciated.

Answer 1

For me, is not a good way to load your view like this.
It would be better to load a rootViewController in your AppDelegate and add your current view depending of your plist inside the RootViewController :
AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
RootViewController *rootViewController = [[RootViewController alloc] initWithNibName:#"RootViewController" bundle:nil];
self.window.rootViewController = rootViewController;
[self.window makeKeyAndVisible];
return YES;
}
After in your RootViewController add a subview of the current view depending on your plist :
RootViewController.m
#pragma mark - View management
- (void)viewDidLoad
{
[super viewDidLoad];
NSDictionary *prefsDictionary = [prefsController readPrefs];
NSLog(#"%#", prefsDictionary);
NSString *projectListBoolString = [prefsDictionary objectForKey:#"ProjectListAvailable"];
NSString *installsBoolString = [prefsDictionary objectForKey:#"InstallsAvailable"];
NSString *finishinBoolString = [prefsDictionary objectForKey:#"FinishingAvailable"];
if (([projectListBoolString isEqualToString:#"T"]) && ([installsBoolString isEqualToString:#"F"]) && ([finishinBoolString isEqualToString:#"F"])) {
self.getProjectListViewController = [[GetProjectListViewController alloc] initWithNibName:#"GetProjectListViewController" bundle:nil];
// Add View Controller
[self.view addSubview:self.getProjectListViewController.view
}
else if (([projectListBoolString isEqualToString:#"T"]) && ([installsBoolString isEqualToString:#"T"]) && ([finishinBoolString isEqualToString:#"T"])) {
self.currentProjectListViewController = [[CurrentProjectListViewController alloc] initWithNibName:#"CurrentProjectListViewController" bundle:nil];
// Add View Controller
[self.view addSubview:self.currentProjectListViewController.view];
}
else {
self.viewController = [[ViewController alloc] initWithNibName:#"ViewController" bundle:nil];
// Add View Controller
[self.view addSubview:self.viewController.view];
}
}