CFDictionary返回空

Question

我第一次尝试使用核心基金会，我肯定遗漏了什么。我试图使用NSObjects作为CFMutableDictionaryRef的键和值。

我有以下测试应用程序：

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
    NSString* key = @"testKey";
    NSObject* item = [[NSObject alloc] init];

    const CFDictionaryKeyCallBacks keyCB = kCFTypeDictionaryKeyCallBacks;
    const CFDictionaryValueCallBacks valCB = kCFTypeDictionaryValueCallBacks;

    CFMutableDictionaryRef dict = CFDictionaryCreateMutable(NULL, 0, &keyCB, &valCB);
    CFDictionaryAddValue(dict, item, key);
    NSLog(@"[CH] added = %@", CFDictionaryGetValue(dict, key));
    NSLog(@"[CH] size = %ld", CFDictionaryGetCount(dict));


}

产出：

2011-07-14 16:47:40.568 TestCoreFoundation61343:903添加= (null) 2011-07-14 16:47:40.578 TestCoreFoundation61343:903 size = 1

Answer 1

您可以向后调用CFDictionaryAddValue。它是dict，key，然后是value：

CFDictionaryAddValue(dict, key, item);

除此之外，看上去还不错。

希望这能有所帮助。