如何讓這個UINavigationController尋求更優雅的代碼？

Question

-(UINavigationController *) navigationControllerOfParentOrSelf //These 2 functions are short so I just go ahead 
{ 
    UIViewController * current=self; 
    while (current) { 
     UINavigationController * nav = current.navigationController; 
     if (nav) { 
      return nav; 
     } 
     current=current.parentViewController; 
    } 
    return nil; 
} 

-(UITabBarController *) tabBarControllerOfParentOrSelf 
{ 
    UIViewController * current=self; 
    while (current) { 
     UITabBarController * tc = current.tabBarController; 
     if (tc) { 
      return tc; 
     } 
     current=current.parentViewController; 
    } 
    return nil; 
} 

看起來像很多重複的代碼。

基本上我只想知道一個UIViewController是否在UINavigationController中。事情是navigationController屬性通常爲零時的UIViewController是childViewController

Answer 1

我建議是這樣的：

-(UINavigationController *) navigationControllerOfParentOrSelf 
{ 
    return [self parrentControllerOfParrentOrSelfWithGetter: @selector(navigationController)]; 
} 

-(UITabBarController *) tabBarControllerOfParentOrSelf 
{ 
    return [self parrentControllerOfParrentOrSelfWithGetter: @selector(tabBarController)]; 

} 

- (id) parrentControllerOfParrentOrSelfWithGetter: (SEL) getter 
{ 
    UIViewController * current=self; 
    while (current) { 
     id res = [current performSelector: getter]; 
     if (res) { 
      return tc; 
     } 
     current=current.parentViewController; 
    } 
    return nil; 
} 

Answer 2

你可以不喜歡它：

-(id) getViewController:(BOOL)isNavController 
{ 
    id controller = nil; 
    if(isNavController) 
    { 
     controller = self.navigationController; 
    } 
    else 
    { 
     controller = self.tabBarController; 
    } 

    return controller; 
}