消息应该存在

Question

[CFString isEqualToString:]: message sent to deallocated instance

这是我得到的错误。我有一个视图控制器的属性是一个NSMutableArray，它包含一些Player对象。

然后我有一个方法切换到另一个视图，我可以添加和删除播放器。当我加载下一个视图时，我将一个指向第一个视图的指针传递给第二个视图。然后我使用[previousView.playerList addObject:p];更新了阵列，其中p是新创建的播放器对象。

但是当我尝试在第二个视图的表格视图中显示玩家列表时出现错误。当我尝试访问[previousView.playerlist objectAtIndex:[indexPath row]];时，出现上述错误。

下面的代码：

这是第一个视图，它加载第二个并将自己第二的财产。

- (IBAction) addPlayerButton:(id)sender { 
    [self retain]; 
    PlayerListViewController *playerListViewController = [[PlayerListViewController alloc] init]; 
    playerListViewController.previousView = self; 
    [UIView transitionFromView:self.view toView:playerListViewController.view duration:0.5 options:UIViewAnimationOptionTransitionFlipFromLeft completion:nil]; 
} 

这是我初始化播放器并将其添加到数组的地方。

- (IBAction)addPlayer:(id)sender { 
    Player *p = [[[Player alloc] initWithPlayerName:playerNameField.text withOrder:[previousView.playerList count] withDelegate:previousView] retain]; 
    [previousView.playerList addObject:p]; 
    [playerNameField resignFirstResponder]; 
    [playerTableView reloadData]; 
} 

这里是从哪里获得我的错误

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { 
    static NSString *cellIdentifier = @"MyCell"; 

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier]; 
    if (cell == nil) { 
     cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier] autorelease]; 
    } 
    Player* p = [previousView.playerList objectAtIndex:[indexPath row]]; 
    [cell.textLabel setText:[p playerName]]; 
    cell.accessoryType = UITableViewCellAccessoryCheckmark; 

    return cell; 
} 

我得到的，我设置单元格文本行的错误。 [cell.textLabel setText:[p playerName]];

有没有人知道我在哪里搞砸了？如果需要，我会发布更多的代码。

我修剪Player.m只包括综合和初始化，因为其余的是很多代码，这并不是真的与这个错误，因为它不被称为。

Player.h

@protocol playerProtocol <NSObject> 

@optional 
- (void) playerDied:(id)playerObject; 
- (void) playerWasAdded:(id)playerObject; 
- (void) playerLifeDidChange:(id)playerObject; 
@end 

@interface Player : NSObject { 
    id <playerProtocol> delegate; 
} 
@property (nonatomic,retain) NSString *playerName; 
@property (nonatomic, readwrite) int playerLife; 
@property (nonatomic, readwrite) int playerPoison; 
@property (nonatomic, readwrite) int order; 
@property (nonatomic, readwrite) Boolean invincible; 
@property (nonatomic, assign) id <playerProtocol>delegate; 
@property (nonatomic, retain) UIView *viewPane; 
@property (nonatomic) Boolean shown; 
@property (nonatomic, readwrite) int minusButton; 
@property (nonatomic, readwrite) int plusButton; 
@property (nonatomic, retain) UIImageView *readout; 
@property (nonatomic, retain) NSArray *playerLifeNumerals; 


- (id) initWithPlayerName:(NSString *)playersName withOrder:(int)Order withDelegate:(id)d; 
- (void) setPlayerLife:(int)pplayerLife; 
- (void) setPlayerPoison:(int)pplayerPoison; 
- (NSArray *) getLifeNumeralsFromPlayer:(Player *)playerObject; 

@end 

Player.m

@implementation Player 

@synthesize playerLife, playerName, playerPoison, order, delegate, invincible, viewPane, readout, shown, minusButton, plusButton, playerLifeNumerals; 

#pragma mark - Custom Initalizer 

- (id) initWithPlayerName:(NSString *)playersName withOrder:(int)Order withDelegate:(id)d { 

    [super init]; 
    delegate = d; 
    playerLife = 20; 
    playerPoison = 0; 
    order = Order; 
    playerName = playersName; 
    invincible = NO; 
    [delegate playerWasAdded:self]; 
    viewPane = nil; 
    readout = nil; 
    shown = NO; 
    return self; 
} 

而且这里的数组声明@property (nonatomic, retain) NSMutableArray *playerList;

Answer 1

在：

- (id) initWithPlayerName:(NSString *)playersName withOrder:(int)Order withDelegate:(id)d { 

    [super init]; 
    delegate = d; 
    playerLife = 20; 
    playerPoison = 0; 
    order = Order; 
    playerName = playersName; 
    invincible = NO; 
    [delegate playerWasAdded:self]; 
    viewPane = nil; 
    readout = nil; 
    shown = NO; 
    return self; 
} 

你是不是retaini ng playerName。请注意，尽管您已将playerName属性声明为retain（而应该是copy），但您并未使用-initWith…中的属性设置器。相反，您直接访问支持实例变量。由于您直接将playersName分配给实例变量，因此您需要手动发送它-retain（或更好的-copy）。

检查您的其他声明属性是否需要该属性。此外，您应该遵循以下成语：

self = [super init]; 
if (self) { … } 
return self; 

在您的初始器中。

编辑：由于您在多个位置泄漏，您需要仔细检查您的代码与内存管理实践有关。例如，在：

- (IBAction) addPlayerButton:(id)sender { 
    [self retain]; 
    PlayerListViewController *playerListViewController = [[PlayerListViewController alloc] init]; 
    playerListViewController.previousView = self; 
    [UIView transitionFromView:self.view toView:playerListViewController.view duration:0.5 options:UIViewAnimationOptionTransitionFlipFromLeft completion:nil]; 
} 

什么的[self retain]的目的，是有一个平衡的释放？

又如：在：

Player *p = [[[Player alloc] initWithPlayerName:playerNameField.text withOrder:[previousView.playerList count] withDelegate:previousView] retain]; 
[previousView.playerList addObject:p]; 

你从+alloc +1所有权，另一+1从-retain，数组还拥有p，因此另一个+1。您应该将-retain替换为-autorelease以平衡您获得该对象所有权的次数。