如何更新NSUserDefault

Question

我有以下代码,它应该更新NSUserDefaults中的值:

- (id) createBoardWithTitle:(NSString *)pTitle withScores:(NSArray *)pScores andNames:(NSArray *)pNames andDisplayStrings:(NSArray *)pStrings orderBy:(NSString *)pOrder ofType:(NSString *)pType
{

    if((self == [super init]))
    {

        boardEntries = [NSMutableArray arrayWithCapacity:10];

        // Build the data

            for(...){
               // populate boardEntries
            }


        // create an Dictionary to save
        NSDictionary *savedData = [NSDictionary dictionaryWithObjectsAndKeys:pType, @"type", pOrder, @"order", boardEntries, @"entries", nil];

            // Load the old boards
        NSDictionary *existingBoards = [[NSUserDefaults standardUserDefaults] objectForKey:@"BlockDepotLeaderboards"];

            // Create a mutable dictionary to replace the old immutable dictionary
        NSMutableDictionary *newBoards = [NSMutableDictionary dictionaryWithCapacity:[existingBoards count]+1];

            // transfer the old dictionary into the new dictionary
        [newBoards addEntriesFromDictionary:existingBoards];

            // add the new board to the new dictionary
        [newBoards setObject:savedData forKey:pTitle];

            // check to make sure it looks like it should by eye
        NSLog(@"New Boards: %@", newBoards);

            // Replace the old date in NSUserdefaults
        [[NSUserDefaults standardUserDefaults] setObject:newBoards forKey:@"BlockDepotleaderboards"];
            // Update: Do I really need to call this?
        [[NSUserDefaults standardUserDefaults] synchronize];

            // Check to make sure it looks as it should by eye
        NSLog(@" Defaults--- %@", [[NSUserDefaults standardUserDefaults] objectForKey:@"BlockDepotLeaderboards"]);
    }

    return self;

}

据我所知,这是相关的代码.它可能比它需要的更"啰嗦".但据我了解,从NSUserDefaults返回的任何内容都是不可变的,因此我必须将其重新创建为Mutable对象,添加需要添加的内容然后替换NSUserDefaults中的对象.而且我认为我在上面尝试的应该有效.

NSLog的输出(@"New Boards:%@",newBoards)id

New Boards: {
    "Marathon: Times" =     {
        entries =         (
                        {
                displayString = "10:00";
                name = "Tom Elders";
                score = 600;
            },
                        {
                displayString = "10:30";
                name = "A.R. Elders";
                score = 630;
            },
                        {
                displayString = "11:00";
                name = "L. Lancaster-Harm";
                score = 660;
            },

            // and so on.....

        );
        order = ASC;
        type = TIMES;
    };
    String = Test;
}

"String = test"只是一个测试条目,并在AppDelegate.m文件中设置如下:

if(![[NSUserDefaults standardUserDefaults] objectForKey:@"BlockDepotLeaderboards"]){

    NSMutableDictionary *leadboardHolder = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"Test", @"String", nil];      
    [[NSUserDefaults standardUserDefaults] setObject:leadboardHolder forKey:@"BlockDepotLeaderboards"];
    [[NSUserDefaults standardUserDefaults] synchronize];



}else{
    NSLog(@"Leaderboards Dict Exists %@", [NSUserDefaults standardUserDefaults]);
}

所以我知道我所追求的是肯定的.我只是知道这将是一个让我失踪的愚蠢行为.但我无法看到它或弄明白.

任何人都可以看到我搞砸了什么？

Answer 1

据我所知,这是相关的代码.它可能比它需要的更"啰嗦".但据我了解,从NSUserDefaults返回的任何内容都是不可变的,因此我必须将其重新创建为Mutable对象,添加需要添加的内容然后替换NSUserDefaults中的对象.

一种更简单的方法是生成不可变字典的mutableCopy,如下所示:

NSMutableDictionary *newBoards = [[immutableDict mutableCopy] autorelease];
[newBoards setObject:savedData forKey:pTitle];

此外,synchronize还用于强制将用户默认值保存到磁盘.它只会影响您在Finder中打开plist时所看到的内容.从应用程序的角度来看,NSUserDefaults始终是最新的.此外,默认值会每隔一段时间自动保存,因此您可能需要调用的唯一时间synchronize是应用程序终止时.