不可见的'MyController'的@interface声明了选择器

Question

I'm learning iOS development and I found an app source sample in the internet. I'm trying to rewrite it and use it for tabbed layout, and after copying the AppDelegate.m from the sample app, I got the following error:

No Visible @interface for 'FirstViewController' declares the selector alloc

In the following line:

FirstViewController *FirstViewController = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];

This is my full AppDelegate:

#import "AppDelegate.h"

#import "FirstViewController.h"

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.

    FirstViewController *FirstViewController = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];
    self.navigationController = [[UINavigationController alloc] initWithRootViewController:FirstViewController];
    self.navigationController.navigationBar.barStyle = UIBarStyleBlackOpaque;
    self.window.rootViewController = self.navigationController;
    [self.window makeKeyAndVisible];
    return YES;
}

@end

same error (with selector InithWithNibName:bundle ) in my FirstViewController.m file

MyViewController* MyController  = [[MyViewController alloc] initWithNibName:@"MyViewController" bundle:nil];

I don't know what this error means.

Answer 1

You should probably use different names for your variables and classes.

change:

FirstViewController *FirstViewController = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];

to:

FirstViewController *firstViewController = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];