使用 UISearchBar 方法获取 EXC_BAD_ACCESS 崩溃

Question

我有一个 UISearchBar 设置，当它被使用时，它有一个覆盖表的其余部分的覆盖灰色视图，类似于苹果的做法。

当我点击这个变暗的视图时，它会退出搜索模式，这很好，但是当我再次搜索，然后再次点击灰色退出时，它会因 EXC BAD ACCESS 错误而崩溃。

下面是一些相关代码：

崩溃总是在[rvController doneSearching_Clicked:nil];

OverlayViewController.h

@interface OverlayViewController : UIViewController

@property (nonatomic, retain) ChooserViewController *rvController;
@property (nonatomic, retain) CPTViewController *cptViewController;


@implementation OverlayViewController

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

    [rvController doneSearching_Clicked:nil];
    [cptViewController doneSearching_Clicked:nil];
}

- (void) dealloc {
    [rvController release];
    [cptListViewController release];
    [super dealloc];
}

@end

带有搜索栏的实际 VC 代码

- (void) searchBarSearchButtonClicked:(UISearchBar *)theSearchBar
{
    searching = YES;
    [ovController.view removeFromSuperview];
    letUserSelectRow = YES;
    self.tableView.scrollEnabled = YES;
    if (self.mySearchBar.text !=nil)
    {
        NSPredicate *predicate =[NSPredicate predicateWithFormat:@"(name contains[cd] %@) OR (code contains[cd] %@)", self.mySearchBar.text, self.mySearchBar.text];
        [fetchedResultsController.fetchRequest setPredicate:predicate];
    }
    else
    {
        NSPredicate *predicate =[NSPredicate predicateWithFormat:@"All"];
        [fetchedResultsController.fetchRequest setPredicate:predicate];
    }

    NSError *error = nil;
    if (![[self fetchedResultsController] performFetch:&error]) 
    {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        exit(-1);  // Fail
    } 

    self.searchArray = fetchedResultsController.fetchedObjects;

    [mySearchBar resignFirstResponder];

    [self.tableView reloadData];
}

- (void) searchBarTextDidBeginEditing:(UISearchBar *)searchBar
{
    self.navigationItem.leftBarButtonItem = nil;

    if(searching)
        return;

    if(ovController == nil)
        ovController = [[OverlayViewController alloc] initWithNibName:@"OverlayView" bundle:[NSBundle mainBundle]];

    CGFloat yaxis = self.navigationController.navigationBar.frame.size.height;
    CGFloat width = self.view.frame.size.width;
    CGFloat height = self.view.frame.size.height;

    CGRect frame = CGRectMake(0, yaxis, width, height);
    ovController.view.frame = frame;    
    ovController.view.backgroundColor = [UIColor grayColor];
    ovController.view.alpha = 0.5;

    ovController.rvContrller = self;

    [self.tableView insertSubview:ovController.view aboveSubview:self.parentViewController.view];

    searching = YES;
    letUserSelectRow = NO;
    self.tableView.scrollEnabled = NO;

    self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc] 
                                               initWithBarButtonSystemItem:UIBarButtonSystemItemCancel 
                                               target:self action:@selector(doneSearching_Clicked:)] autorelease];
}

- (void) searchBarTextDidEndEditing:(UISearchBar *)searchBar
{
    searchBar.showsCancelButton = NO;
}

- (void)searchBar:(UISearchBar *)theSearchBar textDidChange:(NSString *)searchText 
{
    [self.tableView insertSubview:ovController.view aboveSubview:self.parentViewController.view];

    searching = NO;
    letUserSelectRow = NO;
    self.tableView.scrollEnabled = NO;

    [self.tableView reloadData];
}
- (void) doneSearching_Clicked:(id)sender {

    mySearchBar.text = @"";
    [mySearchBar resignFirstResponder];

    letUserSelectRow = YES;
    searching = NO;
    self.navigationItem.rightBarButtonItem = nil;
    self.tableView.scrollEnabled = YES;

    [ovController.view removeFromSuperview];
    [ovController release];
    ovController = nil;

    [self.tableView reloadData];
    [self.tableView scrollToRowAtIndexPath:0 atScrollPosition:UITableViewScrollPositionTop animated:YES];
}

Answer 1

/// @OverlayView
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

    [rvController doneSearching_Clicked:nil]; ///< Point 1
    [cptViewController doneSearching_Clicked:nil];
}

/// @VC Search bar
- (void) doneSearching_Clicked:(id)sender {

    mySearchBar.text = @"";
    [mySearchBar resignFirstResponder];

    letUserSelectRow = YES;
    searching = NO;
    self.navigationItem.rightBarButtonItem = nil;
    self.tableView.scrollEnabled = YES;

    /// Point 2 
    [ovController.view removeFromSuperview];
    [ovController release];
    ovController = nil;

    [self.tableView reloadData];
    [self.tableView scrollToRowAtIndexPath:0 atScrollPosition:UITableViewScrollPositionTop animated:YES];
}

在Point 1，它会调用-(void)doneSearching_Clicked，然后它会执行Point 2。在Point 2，我认为OverlayView 对象的retainCount 将为0，这意味着它将被释放。因此，OverlayView 拥有的所有指针都可能无效，因为它释放了-(void)dealloc 中的那些对象。根据你的代码，我能知道的就这些了。

编辑：
上述过程可以翻译成以下格式。 -doneSearching_Click 将导致 [self release] 行为。

/// @OverlayView
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

    [rvController doneSearching_Clicked:nil]; ///< Point 1
    /// [self release];  /// the above method will do such thing.
    [cptViewController doneSearching_Clicked:nil];
}

Answer 2

您的代码并非完全不言自明，但我猜您是过度释放ovController。你在ovController 的touchesBegan: 方法中，然后你让它在另一个对象rvContrller 中执行一个方法，它释放调用对象。当尝试从方法调用返回到释放的控制器时，您会收到错误访问错误。