在方法范围内释放“参考”变量

Question

在objective-c (cocoa touch) 中，我有一系列UIViewController 可以在它们之间切换。

- (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];
}

如您所见，我将其中一个视图控制器分配给“nextViewController”。我想知道的是我是否需要释放这个“本地”变量，或者是否可以不理会，因为它只是指向我的一个视图控制器（我在 dealloc 中释放）。我认为不需要发布“标签”，因为它是“原始”，对吗？按钮呢？我不太明白应该和不应该明确发布什么，所以也许我过于谨慎了。提前致谢。

Answer 1

一般来说，您只需 release 一个您已经 retain'd init'd 或 copy'd 的变量。

编辑：

在阅读您的代码多一点之后，您似乎还有其他与错误值有关的问题。下面的代码对我来说更有意义。这假设财务、社交和票务都是@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];
}