Set up a new project for an extensible application.
- Start XCode, and create a new project.
- In the left pane, under iOS, select Application. In the
right pane, select Single View Application.
- Complete the details on the first screen, then click Next to
build an iPhone-only ap that uses ARC (Automatic Reference Counting).Note: You are not required to use ARC; however, if you use MRC (Manual Reference Counting), you are then responsible for manually retaining and releasing your objects. If you plan to use MRC, appropriately adapt the tutorial code to prevent memory leaks and Xcode warnings.
- After you have created your project, you see this screen in Xcode:
Xcode automatically creates some classes: an application delegate, a view controller, and the belonging lib. If you run the app now, you see a grey screen, as no controller logic has yet been implemented.
The ViewController is instantiated in the AppDelegate's didFinishLaunchingWithOptions:
method; it is then assigned to the app's window as root view controller, and finally the
window is made visible - this is all the boilerplate code
does:
@implementation AppDelegate
- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
return YES;
}