关于未找到app委托方法的编译器警告

Question

我需要知道为什么这不起作用，我只是想在两页之间导航。但我一直得到的错误是

  

MobileEliteAppDelegate.m：警告：语义问题：实例方法'-PresentViewController：animated：'not found（返回类型默认为'id'）“。

//
//  MobileEliteAppDelegate.m
//  MobileElite
//
//  Created by Keeano Martin on 8/23/11.
//  Copyright 2011 __Electronic_Payment_Systems__. All rights reserved.
//

#import "MobileEliteAppDelegate.h"
#import "RootViewController.h"

@implementation MobileEliteAppDelegate

@synthesize window = _window;
@synthesize navigationController = _navigationController;
@synthesize usernameTextBox = _usernameTextBox;
@synthesize passwordTextBox = _passwordTextBox;
@synthesize loginButton = _loginButton;

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

// Override point for customization after application launch.
// Add the navigation controller's view to the window and display.
//self.window.rootViewController = self.navigationController;
//[_window addSubview:[RootViewController view]];
[self.window makeKeyAndVisible];
return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application
 {
/*
 Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
 Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
 */
 }

- (void)applicationDidEnterBackground:(UIApplication *)application
 {
/*
 Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
 If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
 */
 }

- (void)applicationWillEnterForeground:(UIApplication *)application
 {
/*
 Called as part of the transition from the background to the inactive state; here you    can undo many of the changes made on entering the background.
 */
 }

- (void)applicationDidBecomeActive:(UIApplication *)application
 {
/*
 Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
 */
}

- (void)applicationWillTerminate:(UIApplication *)application
{
/*
 Called when the application is about to terminate.
 Save data if appropriate.
 See also applicationDidEnterBackground:.
 */
}

- (void)dealloc
{
[_window release];
[_navigationController release];
[_usernameTextBox release];
[_passwordTextBox release];
[_loginButton release];
[super dealloc];
}

- (IBAction)loginButtonClick:(id)sender {
if(_usernameTextBox.text == @"App@eps-na.com" & _passwordTextBox.text == @"eps123")
{
    RootViewController *RVC = [[RootViewController alloc] initWithNibName:nil bundle:nil];
    [self PresentViewController: RVC animated:YES];
    [RVC release];
}

}
@end

我不是Objective C程序员;我必须为我的公司这样做，我通常写在.Net库中。有人可以详细解释两个或更多.xib文件之间的导航是如何工作的吗？