在方法範圍內釋放「引用」變量

Question

在objective-c（cocoa touch）中，我有一系列UIViewControllers，可以在它們之間切換。

- (void)switchViews:(id)sender 
{ 
    UIButton *button = (UIButton *)sender; 
    UIViewController *nextViewController; 
    int tag = button.tag; 

    switch (tag) 
    { 
     // -- has already been created 
     case kFinancialButton: 
      nextViewController = financials; 
      break; 

     case kSocialButton: 
      if (social == nil) 
      { 
       SocialViewController *socialViewController = [[SocialViewController alloc] initWithNibName:@"SocialViewController" bundle:nil]; 
       social = socialViewController; 
       [socialViewController release]; 
      } 
      nextViewController = social; 
      break; 

     case kTicketingButton: 
      if (ticketing == nil) 
      { 
       TicketingViewController *ticketingViewController = [[TicketingViewController alloc] initWithNibName:@"TicketingViewController" bundle:nil]; 
       ticketing = ticketingViewController; 
       [ticketingViewController release]; 
      } 
      nextViewController = ticketing; 
      break; 
    } 

     /////// 
------> // -- [button/nextViewController release]???? 
     /////// 

    [self setActiveButton:button]; 
} 

正如你所看到的，我分配視圖控制器「nextViewController」之一。我想知道的是，如果我需要釋放這個「本地」變量，或者它可以獨自離開，因爲它只是指向我的一個視圖控制器（我在dealloc中發佈）。我不認爲「標籤」需要被釋放，因爲它是「原始的」，是正確的？按鈕怎麼樣？我不太明白什麼應該和不應該明確發佈，所以也許我會過於謹慎。提前致謝。

Answer 1

一般而言，您只需要release一個變量，即您已經有retain'd init'd或copy'd。

編輯：

閱讀你的代碼多一點點之後，好像你有壞的價值觀等問題。下面的代碼對我來說更有意義。這假設財務，社交和票務都是@synthesized ivars。

- (void)switchViews:(id)sender 
{ 
    UIButton *button = (UIButton *)sender; 
    UIViewController *nextViewController; 
    int tag = button.tag; 

    switch (tag) 
    { 
     // -- has already been created 
     case kFinancialButton: 
      nextViewController = self.financials; 
      break; 

     case kSocialButton: 
      if (!social) { 
       self.social = [[[SocialViewController alloc] initWithNibName:@"SocialViewController" bundle:nil] autorelease]; 
      } 
      nextViewController = self.social; 
      break; 

     case kTicketingButton: 
      if (!ticketing) { 
       self.ticketing = [[[TicketingViewController alloc] initWithNibName:@"TicketingViewController" bundle:nil] autorelease]; 
      } 
      nextViewController = self.ticketing; 
      break; 
    } 

    // Do something with nextViewController I'd assume 

    [self setActiveButton:button]; 
}