initWithCoder:和NSKeyedUnarchiver的问题

Question

我目前正在尝试在我的应用程序中添加一个游戏保存功能。最终目标是获取保存到.plist文件中的~300个自定义对象，并在以后再次提取它们。我已经取得了一些进展，但是我对initWithCoder:有一些问题，我对我的技术也不太确定。

UIViewController正在使用以下代码来保存对象(例如，我只向字典中添加了2个对象)：

//Saves the contents to a file using an NSMutableDictionary
-(IBAction)saveContents {

    //Create the dictionary
    NSMutableDictionary *dataToSave = [NSMutableDictionary new];

    //Add objects to the dictionary
    [dataToSave setObject:label.text forKey:@"label.text"];
    [dataToSave setObject:territory forKey:@"territory"];
    [dataToSave setObject:territory2 forKey:@"territory2"];

    //Archive the dictionary and its contents and set a BOOL to indicate if it succeeds
    BOOL success = [NSKeyedArchiver archiveRootObject:dataToSave toFile:[self gameSaveFilePath]];

    //Handle success/failure here...

    //Remove and free the dictionary
    [dataToSave removeAllObjects]; dataToSave = nil;
}

这成功地调用了encodeWithCoder:类中的Territory函数两次：

-(void)encodeWithCoder:(NSCoder *)aCoder {

    NSLog(@"ENCODING");
    [aCoder encodeObject:self.data forKey:@"data"];
    [aCoder encodeInt:self.MMHValue forKey:@"MMHValue"];
    [aCoder encodeObject:self.territoryName forKey:@"territoryName"];
    //Continue with other objects
}

当然，当我查看目录时，文件是存在的。--现在，我遇到的问题是:当运行以下函数时，initWithCoder:函数被成功地调用了两次。initWithCoder:函数中的日志输出它们应该输出的内容，但是UIViewController的loadContents函数中的日志返回0、null等。然而，标签的文本设置是正确的。

//Loads the contents from a file using an NSDictionary
-(IBAction)loadContents {

    //Create a dictionary to load saved data into then load the saved data into the dictionary
    NSDictionary *savedData = [NSKeyedUnarchiver unarchiveObjectWithFile:[self gameSaveFilePath]];

    //Load objects using the dictionary's data
    label.text = [savedData objectForKey:@"label.text"];

    NSLog(@"%i, %i", [territory intAtKey:@"Key4"], [territory2 intAtKey:@"Key4"]);
    NSLog(@"MMH: %i, %i", territory.MMHValue, territory2.MMHValue);
    NSLog(@"NAME: %@, %@", territory.territoryName, territory2.territoryName);

    //Free the dictionary
    savedData = nil;
}

- (id)initWithCoder:(NSCoder *)aDecoder {

    if (self = [super initWithCoder:aDecoder]) {

        NSLog(@"DECODING TERRITORY");

        self.data = [aDecoder decodeObjectForKey:@"data"];
        self.MMHValue = [aDecoder decodeIntForKey:@"MMHValue"];
        self.territoryName = [[aDecoder decodeObjectForKey:@"territoryName"] copy];
        //Continue with other objects
    }

    NSLog(@"DECODED INT: %i", self.MMHValue);
    NSLog(@"DECODED NAME: %@", self.territoryName);
    return self;
}

几个小时以来，我一直在努力让这件事奏效，但没有结果。如果有人对此有任何见解，请帮帮我。另外，我不完全确定我的保存技术是否好(使用NSMutableDictionary存储对对象的引用，这样它就可以输出到一个文件)？谢谢!

Answer 1

我阅读了苹果关于NSKeyedArchiver和NSKeyedUnarchiver的文档，以及一些关于这个主题的博客文章，我意识到自己做错了什么。在将对象编码到文件之后(通过使用键将它们添加到字典中，然后将它们保存到.plist中)，当我尝试对它们进行解码时，我从未实际从新字典中提取值(保存刚刚解码的文件内容的字典)。这也解释了为什么加载label的文本，但territory和territory2没有加载。我将loadContents函数更改为以下内容，现在代码工作了：

-(IBAction)loadContents {

    //Create a dictionary to load saved data into then load the saved data into the dictionary
    NSLog(@"***** STARTING DECODE *****");
    NSDictionary *savedData = [NSKeyedUnarchiver unarchiveObjectWithFile:[self gameSaveFilePath]];
    NSLog(@"***** CALLING initWithCoder: ON OBJECTS *****");
    NSLog(@"***** FINISHED DECODE *****");

    //Load objects using the dictionary's data
    label.text = [savedData objectForKey:@"label.text"];
    territory = [savedData objectForKey:@"territory"];
    territory2 = [savedData objectForKey:@"territory2"];

    //Free the dictionary
    savedData = nil;
}