NSMutableArray Init麻烦

Question

我有这个方法处理一些我似乎无法正确的数组.与alloc和init相关的东西.

- (void)addBookmark
{
    // Get the user defaults object
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];

    // Load your bookmarks (editable array)
    NSMutableArray *bookmarks = [[NSMutableArray alloc]init];
    NSArray *bookmarksLoaded = [userDefaults arrayForKey:@"bookmarks"];
    if (bookmarksLoaded != nil) {
        [bookmarks initWithArray:bookmarksLoaded];
    } else {
        [bookmarks init];
    }

    // Add a bookmark
    NSMutableDictionary *bookmark = [NSMutableDictionary new];
    [bookmark setValue:@"value" forKey:@"name"];
    [bookmark setValue:@"value" forKey:@"description"];
    [bookmark setValue:@"value" forKey:@"code"];
    [bookmarks addObject:bookmark];

    // Save your (updated) bookmarks
    [userDefaults setObject:bookmarks forKey:@"bookmarks"];
    [userDefaults synchronize];

    // Memory cleanup
    [bookmarks release];
}

Answer 1

你是对的 - 这是你对alloc/init的使用.你应该只有init一个对象一次.你想要这样的东西:

// Load your bookmarks (editable array)
NSMutableArray *bookmarks = nil; // we'll initialize it later
NSArray *bookmarksLoaded = [userDefaults arrayForKey:@"bookmarks"];
if (bookmarksLoaded) { // shortcut for bookmarksLoaded != nil
    bookmarks = [[NSMutableArray alloc] initWithArray:bookmarksLoaded];
} else {
    bookmarks = [[NSMutableArray alloc] init];
}

// Add a bookmark
NSMutableDictionary *bookmark = [NSMutableDictionary dictionary];

如果你使用dictionary而不是new,你得到一个你不必担心的自动释放对象(new不在Cocoa中使用).就像你拥有它一样,你正在泄露记忆.