cocoa - 将 NSMutableDictonary 添加到 NSMutableArray 但对象被替换

Question

每当我向我的 NSMutableArray 添加一个新对象 NSMutableDictionay 时，它怎么会替换我以前的对象？

例如：

[appDelegate.tracksDict setObject:currentTrackTitle forKey:@"track_title"];
[appDelegate.tracksDict setObject:currentTrackTopic forKey:@"topic"];
[appDelegate.tracksArray addObject:[appDelegate.tracksDict copy]];

它的印刷...

2010-10-01 14:03:35.021 XML[48889:207]Tracks Array: {
    topic = "Cold Calling";
    "track_title" = "Sleeping and selling";
}
2010-10-01 14:03:35.021 XML[48889:207]Tracks Array: {
    topic = "Gate Keeper";
    "track_title" = "Selling like a chicken";
}
2010-10-01 14:03:35.021 XML[48889:207]Tracks Array: {
    topic = "Gate Keeper";
    "track_title" = "Don't you try to sell";
}

而不是像...

2010-10-01 14:03:35.021 XML[48889:207]Tracks Array: {
    topic = "Cold Calling";
    track_title = "Sleeping and selling";

    topic = "Gate Keeper";
    track_title = "Selling like a chicken";

    topic = "Gate Keeper";
    track_title = "Selling like a chicken";
}

我敢肯定这是愚蠢的，因为我不太懂这种语言。

Answer 1

根据您发布的“打印”，您的问题很难理解，但听起来您想要一个 NSDictionary 对象的 NSArray。NSDictionary 只能为给定键保存一个对象，但可以拥有（实际上）无限的键。看起来您需要的是构建一组字典，每首曲目一个。