iphone - NSMutableArray 不获取 XML 值

Question

我正在尝试使用 TBXML 解析 XML 文件并将值放入多维 NSMutableArray 但问题是这些值没有被添加到数组中，如果我输出这些值然后它返回 null 和 0。

这是我的代码:

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self downloadAndParseXml:@"http://www.w3schools.com/XML/note.xml"];

    // RETURNS 0
    NSLog(@"weatherArray count: %d", [weatherArray count]);

    // RETURNS NULL
    NSLog(@"weatherArray value: %@", weatherArray[0][0]);
}

- (void)downloadAndParseXml:(NSString *)xmlUrl
{
    // Allocating the array
    weatherArray = [NSMutableArray array];

    TBXMLSuccessBlock sBlock = ^(TBXML *tbxmlDocument) {
        if (tbxmlDocument.rootXMLElement)
            [self fillArrayWithXmlContents:tbxmlDocument.rootXMLElement];
    };

    TBXMLFailureBlock fBlock = ^(TBXML *tbxmlDocument, NSError *error) {
        NSLog(@"Failureblock: %@\n%@", [error localizedDescription], [error userInfo]);
    };

    [TBXML newTBXMLWithURL:[NSURL URLWithString:xmlUrl] success:sBlock failure:fBlock];
}

- (void)fillArrayWithXmlContents:(TBXMLElement *)element {
    do {
        if (element->firstChild)
            [self fillArrayWithXmlContents:element->firstChild];

        if ([[TBXML elementName:element] isEqualToString:@"note"]) {

            // Adding values into the multidimensional array
            [weatherArray addObject:[NSArray arrayWithObjects:
                [TBXML textForElement:[TBXML childElementNamed:@"to" parentElement:element]],
                [TBXML textForElement:[TBXML childElementNamed:@"from" parentElement:element]],
                [TBXML textForElement:[TBXML childElementNamed:@"heading" parentElement:element]],
                [TBXML textForElement:[TBXML childElementNamed:@"body" parentElement:element]], NULL]];

            // Correct value is getting logged
            NSLog(@"weatherArray value: %@", weatherArray[0][0]);
        }
    } while ((element = element->nextSibling));
}

Answer 1

可能你需要做的是等待进程完成，而 block 实际上不知道你在里面做了什么，或者我会说内部函数没有被 block 捕获。所以使用数组(仅在 block 完成后调用正在使用您的数组的函数。

示例:

TBXMLSuccessBlock s = ^(TBXML *tbxml) {
    NSLog(@"yes");
    // Do something with TBXML object "tbxml/add it ur array
   //Here you call the function which is about to use your array.

};

//Not outside the block.

编辑:引用这个==> How do I avoid capturing self in blocks when implementing an API?