如何使用iPhone和iPad两个输出启动项目？

alt text http://www.balexandre.com/temp/2010-04-17_1242.png

alt text http://www.balexandre.com/temp/2010-04-17_1241.png

然后,如果你想切换到每个设备的XIB文件,比如说,MainView for iPhone是A而MainView for iPad是B,你在AppDelegate中添加：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

    // The default have the line below,let us comment it
    //MainViewController *aController = [[MainViewController alloc] initWithNibName:@"MainView" bundle:nil];

    // Our main controller
    MainViewController *aController = nil;

    // Is this OS 3.2.0+ ?
    #if __IPHONE_OS_VERSION_MAX_ALLOWED >= 30200

    if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
            // It's an iPad,let's set the MainView to our MainView-iPad
        aController = [[MainViewController alloc] 
                              initWithNibName:@"MainView-iPad" bundle:nil];
    else 
            // This is a 3.2.0+ but not an iPad (for future,when iPhone runs with same OS than iPad)
        aController = [[MainViewController alloc] 
                              initWithNibName:@"MainView" bundle:nil];

    #else
        // It's an iPhone (OS < 3.2.0)
        aController = [[MainViewController alloc] initWithNibName:@"MainView" bundle:nil];
    #endif

    // Let's continue our default code 
    self.mainViewController = aController;
    [aController release];

    mainViewController.view.frame = [UIScreen mainScreen].applicationFrame;
    [window addSubview:[mainViewController view]];
    [window makeKeyAndVisible];

    return YES;
}