Question

我有一个基于拆分视图控制器的应用程序。在详细视图控制器中，将其称为FirstViewController，当用户按下按钮时，我使用新的视图控制器更新视图控制器，将其称为SecondViewContorller，如下所示：

- (void) buttonPressed:(id)sender {
     UIViewController <SubstitutableDetailViewController> *detailViewController = nil;

     SecondViewController *secondVC = [[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil];
     ...
     detailViewController = secondVC;

     MyAppDelegate *delegate = [[UIApplication sharedApplication] delegate];
     UINavigationController *nav = (UINavigationController *)[delegate.splitViewController.viewControllers objectAtIndex: 0];
     NSArray *viewControllers = [NSArray arrayWithObjects:nav, detailViewController, nil];
     self.splitViewController.viewControllers = viewControllers;

 ...

    [detailViewController release];

}

在SecondViewController中，我们在某些时候有：

 MyAppDelegate *delegate = [[UIApplication sharedApplication] delegate];
 UINavigationController *nav = (UINavigationController *)[delegate.splitViewController.viewControllers objectAtIndex: 0];
 NSArray *array = nav.viewControllers;
 // Retrieve the master view controller
 MasterViewController *masterVC = [array objectAtIndex:[array count] - 1];
 [masterVC selectRowManually:[NSIndexPath indexPathForRow:0 inSection:0]];

并在selectRowManually内部再次初始化FirstViewController：

 UIViewController <SubstitutableDetailViewController> *detailViewController = nil;

 if (rowNo == 0) {
      FirstViewController *newDetailViewController = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];
      detailViewController = newDetailViewController;
 }
 ...

 UINavigationController *nav = (UINavigationController *)[delegate.splitViewController.viewControllers objectAtIndex: 0];

 // Update the split view controller's view controllers array.
 NSArray *viewControllers = [[NSArray alloc] initWithObjects:nav, detailViewController, nil];
 delegate.splitViewController.viewControllers = viewControllers;
 [viewControllers release];

 ...

 [detailViewController release];

如果我在此时模拟内存警告（在再次显示FirstViewController之后），我会得到一个

-[UIView _invalidateSubviewCache]: message sent to deallocated instance ...

堆栈跟踪

#0     0x012dd057 in ___forwarding___
#1     0x012dcf22 in __forwarding_prep_0___
#2     0x00b49a55 in -[UIView dealloc]
#3     0x00bbe52a in -[UIViewController setView:]
#4     0x00bc0eec in -[UIViewController unloadViewForced:]
#5     0x00bbcb0a in -[UIViewController unloadViewIfReloadable]
#6     0x00bbc15b in -[UIViewController didReceiveMemoryWarning]
#7     0x0006aec7 in -[SecondViewController didReceiveMemoryWarning] at SecondViewController.m:385
...

第385行是

[super didReceiveMemoryWarning];

如果在SecondViewController的buttonPressed方法中我注释了我发布detailViewContorller的行，一切都很好，但是我泄漏了内存。如果我按原样离开该行，那么在内存警告的情况下，应用程序崩溃。

我该怎么办？

谢谢，米哈伊

Answer 1

我很想知道你发布detailViewController而不是secondVC的第一个代码块？因为你的secondVC没有在方法结束时发布。您应该在dealloc方法中释放detailViewController而不是SplitViewAppDelegate，因为它是拆分视图的根视图的一部分。

欢呼，希望它有所帮助。

释放详细信息视图控制器会导致内存问题

1 个答案: