objective-c - 试图将 XML 元素 NSMutableString 添加到 NSMutableArray .. 不工作

Question

我正在尝试将特定名称的元素添加到 NSMutableArray，这是我从 XML 文件中获取的。我追求元素。这里的第一个 NSLog 正确输出：

Found an element named: image with a value of: http://media.giantbomb.com/uploads/1/10353/2320941-untitledb_tiny.jpg

第二个 NSLog 正确输出：

I'm about to try adding a game called Bayonetta 2 to the array

第三个 NSLog 总是告诉我数组中有零个条目。我没有收到任何错误[_listOfGameNames addObject: element];，所以我不知道为什么它没有将它添加到数组中。

对我有什么想法吗？这是完整的代码：

- (void) searchWithString: (NSString *)string {
    NSString *searchString = [NSString stringWithFormat: @"http://api.giantbomb.com/search/?api_key=MYKEY12345BLAHBLAH&resources=game&format=xml&query=%@", string];
    NSURL *searchURL = [NSURL URLWithString: searchString];
    parser = [[NSXMLParser alloc] initWithContentsOfURL: searchURL];
    [parser setDelegate:self];
    [parser parse];
    // NSLog(@"XMLParser just reached the end of its initWithString method. The string was %@",  searchURL);
    NSLog(@"There are %u elements in the List Of Game Names array", [_listOfGameNames count]);
}

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict {
    element = [NSMutableString string];
}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
    NSLog(@"Found an element named: %@ with a value of: %@", elementName, element);
    if ([elementName isEqualToString:@"name"]) {
        NSLog(@"I'm about to try adding a game called %@ to the array", element);
        [_listOfGameNames addObject: element];
        NSLog(@"I added an element to the array, making a total of %u", [_listOfGameNames count]);
    }
}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
    if(element == nil) element = [[NSMutableString alloc] init];
    [element appendString:string];
}

Answer 1

答：没有初始化可变数组！

Answer 2

您需要初始化数组。你可以实现Getter。

-(NSMutableArray *) listOfGameNames
{
    if(!_listOfGameNames){
        _listOfGameNames = [[NSMutableArray alloc] init];
    }

    return _listOfGameNames;
}