Using Xcode, create a Window-based Application project and name it WinBasedApp. Observe the files created for this project type (see Figure 7-1). Apart from the other, usual supporting file, note that there is only one XIB file (MainWindow.xib) and two delegate files (WinBasedAppAppDelegate.h and WinBasedAppAppDelegate.m).

Press Command-R to test the application, and you will realize that an empty screen is displayed on the iPhone Simulator. This is because the Window-based Application template provides only the skeleton structure for a simple iPhone application containing just a window and the application delegate.

Back in Xcode, double-click MainWindow.xib to edit it in Interface Builder. Observe that there are four items in the MainWindow.xib window (see Figure 7-2):

Figure 7.1. Figure 7-1

Figure 7.2. Figure 7-2

From the Library window, drag and drop a View Controller item onto the MainWindow.xib window (see Figure 7-3). You will connect this View Controller item to a view that you will add to the project.

Figure 7.3. Figure 7-3

Back in Xcode, right-click the Classes group in Xcode and add a new file. Select the UIViewController subclass item and name it MyViewController. As you will be adding the XIB file manually in the later steps, uncheck the "With XIB for user interface" checkbox. Xcode should now look like Figure 7-4. The two files will serve as the View Controller class for the View Controller item you have added previously in Interface Builder.

Figure 7.4. Figure 7-4

Right-click the Resources group in Xcode and add a new file. Select the View XIB item and name it MyView.xib. Xcode should now look like Figure 7-5.

Figure 7.5. Figure 7-5

Back in Interface Builder, select the View Controller item in the MainWindow.xib window and view its Identity Inspector window. In the Class drop-down list, select MyViewController (see Figure 7-6). The name of the View Controller will now change to My View Controller.

Figure 7.6. Figure 7-6

View the Attributes Inspector window for the My View Controller, and for the NIB Name drop-down list, select MyView (see Figure 7-7).

Figure 7.7. Figure 7-7

Double-click MyView.xib in Xcode to edit it in Interface Builder. In the MyView.xib window, select the File's Owner item and in its Identity Inspector window, select the MyViewController as its Class name (see Figure 7-8). This means that the XIB file will be controlled by the MyViewController class.

Figure 7.8. Figure 7-8

Control-click and drag the File's Owner item to the View item. Select view.

Double-click the View item in the MyView.xib window and add a Button view to the View window (see Figure 7-9).

Figure 7.9. Figure 7-9

Back in Xcode, insert the bold lines in the following code into the WinBasedAppAppDelegate.h file:

#import <UIKit/UIKit.h>

@class MyViewController;

@interface WinBasedAppAppDelegate : NSObject <UIApplicationDelegate> {
    UIWindow *window;

    //---create an instance of the view controller---
    MyViewController *myViewController;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;

//---expose the view controller as a property---
@property (nonatomic, retain) IBOutlet MyViewController *myViewController;

@end

In the WinBasedAppAppDelegate.m file, insert the following code lines that appear in bold:

#import "WinBasedAppAppDelegate.h"

#import "MyViewController.h"

@implementation WinBasedAppAppDelegate

@synthesize window;

//---synthesize the property---
@synthesize myViewController;

- (void)applicationDidFinishLaunching:(UIApplication *)application {

    // Override point for customization after application launch
    //---add the new view to the current window---
    [window addSubview:myViewController.view];

    [window makeKeyAndVisible];
}

- (void)dealloc {
    [myViewController release];
    [window release];
    [super dealloc];
}

@end

In the MainWindow.xib window, Control-click and drag the Win Based App App Delegate item to the My View Controller item (see Figure 7-10). Select myViewController. This will associate the window with the View Controller.

Figure 7.10. Figure 7-10

That's it! Press Command-R to test the application on the iPhone Simulator. You should now see the button appearing on the main screen of the application (see Figure 7-11).

Figure 7.11. Figure 7-11

Using the same project created in the previous section, add the following code that appears in bold to the MySecondViewController.m file:

#import "MySecondViewController.h"

#import "MyViewController.h"

@implementation MySecondViewController
@synthesize label, button;

//---create an instance of the view controller---
MyViewController *myViewController;

-(IBAction) buttonClicked: (id) sender{

    //---add the view of the view controller to the current View---
    myViewController = [[MyViewController alloc]
                           initWithNibName:@"MyView" bundle:nil];
    [self.view addSubview:myViewController.view];

    //---comment out this section---
    /*
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Action invoked!"
                             message:@"Button clicked!"
                             delegate:self
                             cancelButtonTitle:@"OK"
                             otherButtonTitles:nil];
    [alert show];
    [alert release];
    */

}

- (void)dealloc {
    [myViewController release];
    [label release];
    [super dealloc];
}

Declare a btnClicked: action in the MyViewController.h file:

#import <UIKit/UIKit.h>

@interface MyViewController : UIViewController {

}

-(IBAction) btnClicked:(id) sender;

@end

In the MyViewController.m file, define the btnClicked: action as follows:

-(IBAction) btnClicked:(id) sender{
    //---remove the current view; essentially hiding the view---
    [self.view removeFromSuperview];
}

Double-click the MyView.xib file to edit it in Interface Builder.

Control-click and drag the OK button in the View window to the File's Owner item in the MyView.xib window and select btnClicked:.

Back in Xcode, press Command-R to test the application. When you now click the OK button in the main View, you are brought to the second View (see Figure 7-15). To close the second View, press the OK button.

Figure 7.15. Figure 7-15

Using the same project, add the following code that appears in bold to the MySecondViewController.m file:

-(IBAction) buttonClicked: (id) sender{

    myViewController = [[MyViewController alloc]
                                 initWithNibName:@"MyView" bundle:nil];

    [UIView beginAnimations:@"flipping view" context:nil];
    [UIView setAnimationDuration:1];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
    [UIView setAnimationTransition: UIViewAnimationTransitionFlipFromLeft
            forView:self.view cache:YES];

    [self.view addSubview:myViewController.view];

    [UIView commitAnimations];
}

In the MyViewController.m file, add the following code that appears in bold:

-(IBAction) btnClicked:(id) sender{

    [UIView beginAnimations:@"flipping view" context:nil];
    [UIView setAnimationDuration:1];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseIn];
    [UIView setAnimationTransition: UIViewAnimationTransitionFlipFromRight
        forView:self.view.superview cache:YES];

    [self.view removeFromSuperview];

    [UIView commitAnimations];
}

Press Command-R to test the application on the iPhone Simulator. Click the OK buttons on both Views and notice the direction in which the two Views flipped to one another (see Figure 7-16).

Figure 7.16. Figure 7-16