iPhone – 归档自定义对象数组

我已经尝试了几个小时,我无法解决这个问题.

我正在制作一个可以保存未完成的国际象棋游戏的应用程序,所以我正在尝试将数组写入文件.

如果有意义的话,这就是数组：

-NSMutableArray savedGames
--GameSave a
---NSMutableArray board;
----Piece a,b,c,etc.
-----some ints
---NSString whitePlayer,blackPlayer;
---int playerOnTop,turn;
--GameSave b
---NSMutableArray board;
----Piece a,turn;

等等

这些是我的NSCoding方法：

GameSave.m

- (void)encodeWithCoder:(NSCoder *)coder {
    [coder encodeObject:whitePlayer forKey:@"whitePlayer"];
    [coder encodeObject:blackPlayer forKey:@"blackPlayer"];
    [coder encodeInt:playerOnTop forKey:@"playerOnTop"];
    [coder encodeInt:turn forKey:@"turn"];
    [coder encodeObject:board forKey:@"board"];
}

- (id)initWithCoder:(NSCoder *)coder {
    self = [[GameSave alloc] init];
    if (self != nil)
    {
        board = [coder decodeObjectForKey:@"board"];
        whitePlayer = [coder decodeObjectForKey:@"whitePlayer"];
        blackPlayer = [coder decodeObjectForKey:@"blackPlayer"];
        playerOnTop = [coder decodeIntForKey:@"playerOnTop"];
        turn = [coder decodeIntForKey:@"turn"];
    }   
    return self;
}

Piece.m

- (void)encodeWithCoder:(NSCoder *)coder {
    [coder encodeInt:color forKey:@"color"];
    [coder encodeInt:piece forKey:@"piece"];
    [coder encodeInt:row forKey:@"row"];
    [coder encodeInt:column forKey:@"column"];
}

- (id)initWithCoder:(NSCoder *)coder {
    self = [[Piece alloc] init];
    if (self != nil)
    {
        color = [coder decodeIntForKey:@"color"];
        piece = [coder decodeIntForKey:@"piece"];
        row = [coder decodeIntForKey:@"row"];
        column = [coder decodeIntForKey:@"column"];
    }   
    return self;
}

这是试图存档并保存到文件的代码：

- (void)saveGame {
    ChessSaverAppDelegate *delegate = (ChessSaverAppDelegate *) [[UIApplication sharedApplication] delegate];
    [[delegate gameSave] setBoard:board];

    NSMutableArray *savedGames = [NSKeyedUnarchiver unarchiveObjectWithFile:[self dataFilePath]];
    if (savedGames == nil) {
        [NSKeyedArchiver archiveRootObject:[delegate gameSave] toFile:[self dataFilePath]];
    } else {
        [savedGames addObject:[delegate gameSave]];
        [NSKeyedArchiver archiveRootObject:savedGames toFile:[self dataFilePath]];
    }
}

- (NSString *)dataFilePath {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    return [documentsDirectory stringByAppendingPathComponent:@"gameSaves.plist"];
}

对不起,这是问题所在：

设置一些断点后,在-saveGame的这一行之后会出现错误：
    [NSKeyedArchiver archiveRootObject：savedGames toFile：[self dataFilePath]];

这就是控制台中显示的内容：

2010-05-11 17:04:08.852 ChessSaver[62065:207] *** -[NSCFType encodeWithCoder:]: unrecognized selector sent to instance 0x3d3cd30
2010-05-11 17:04:08.891 ChessSaver[62065:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException',reason: '*** -[NSCFType encodeWithCoder:]: unrecognized selector sent to instance 0x3d3cd30'
2010-05-11 17:04:08.908 ChessSaver[62065:207] Stack: (
    32339035,31077641,32720955,32290422,32143042,238843,25827,564412,342037,606848,17686,2733061,4646817,3140430,3149167,3144379,2837983,2746312,2773089,41684313,32123776,32119880,41678357,41678554,2777007,9884,9738
)

如果重要,则从导航控制器中的UIBarButton调用-saveGame.

任何帮助表示赞赏,谢谢.

解决方法

这是错的：

- (id)initWithCoder:(NSCoder *)coder {
    self = [[Piece alloc] init];
    if (self != nil)
    {

当initWithCoder：被调用时,已经分配了类的实例.在您的代码中,您正在泄漏该实例.你应该这样做：

- (id)initWithCoder:(NSCoder *)coder {
    self = [super init]; // or [self init] if needed
    if (self != nil)
    {

此外,当您解码对象时,您不拥有它,因此您需要保留它.

board = [[coder decodeObjectForKey:@"board"] retain];

如果你没有“获得”保留/释放规则,现在就学习它们,否则你将不断地用脚射击.

此外,您的saveGame方法有几个问题.

>如果savedGames为nil,则表示您将对象而非数组保存到文件中.这意味着在下次运行时,未归档的对象将不是您期望的数组.
>未归档的数组是不可变的.将类型声明为NSMutableArray并不重要,如果归档可变数组,则将在unarchive上获得不可变数组.如果要修改它,则需要在unarchived数组上调用mutableCopy.

我完全不确定异常,但是修复了上述问题,要么它会消失,要么解决方案会变得更容易找到.