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Question

我一直收到这个错误 - 不兼容的指针类型将'ViewController'传递给'UIViewController *'类型的参数，并且无法找出错误。

这是错误的代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.

    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    return YES;
}