如何使用GDataXML解析器解析此xml？

Question

<list> 
    <OrderData HASH="1408108039"></OrderData> 
    <OrderData HASH="208524692"> 
     <id>97</id> 
     <customer> 
      <CustomerData HASH="2128670187"></CustomerData></customer> 
     <billingAddress></billingAddress><deliveryAddress></deliveryAddress> 
     <orderDetail> 
      <list> 
       <OrderDetailData HASH="516790072"></OrderDetailData> 
       <OrderDetailData HASH="11226247"></OrderDetailData> 
       <OrderDetailData HASH="11226247"></OrderDetailData> 
      </list> 
     </orderDetail> 
     <log/> 
    </OrderData> 
    <OrderData HASH="1502226778"></OrderData> 
</list> 

我找不到解決方案找到OrderDetailData元素的數量？我也讀了http://iphonebyradix.blogspot.com/2011/03/using-gdata-to-parse-xml-file.html這個網址。

在此先感謝。

編輯：

我再解釋我的要求。在這個XML中將會有多個OrderData元素。現在我必須計算來自特定OrderData元素的OrderDetailData元素的數量。假設根據我的xml，當前解析的xml有一個OrderData元素，名爲id，它的值是97.現在，我必須計算在OrderData (which id`是97中包含多少個OrderDetailData元素。

Answer 1

這是一個簡單的例子如何檢索一些數據。這個例子非常簡單，不使用XPath表達式。我建議你先理解它是如何工作的，然後使用XPath表達式。在我看來，如果您無法理解解析器的工作方式，那麼使用XPath表達式就沒有用處了。

NSString* path = [[NSBundle mainBundle] pathForResource:@"test2" ofType:@"xml"]; 

NSData *xmlData = [[NSMutableData alloc] initWithContentsOfFile:path]; 
NSError *error; 
GDataXMLDocument *doc = [[GDataXMLDocument alloc] initWithData:xmlData 
                 options:0 error:&error]; 
//NSLog(@"%@", doc.rootElement); // print the whole xml 

NSArray *orderDataArray = [doc.rootElement elementsForName:@"OrderData"]; 

for (GDataXMLElement *orderDataElement in orderDataArray) { 

    if([orderDataElement childCount] > 0) 
    {    
     NSString *attributeForOrderDataElement = [(GDataXMLElement *) [orderDataElement attributeForName:@"HASH"] stringValue]; 

     NSLog(@"attributeForOrderDataElement has value %@", attributeForOrderDataElement); 

     GDataXMLElement* idElement = (GDataXMLElement*)[[orderDataElement elementsForName:@"id"] objectAtIndex:0]; 

     NSLog(@"id has value %@", idElement.stringValue); 

     GDataXMLElement* orderDetailElement = (GDataXMLElement*)[[orderDataElement elementsForName:@"orderDetail"] objectAtIndex:0]; 

     GDataXMLElement* listElement = (GDataXMLElement*)[[orderDetailElement elementsForName:@"list"] objectAtIndex:0];    

     NSArray* orderDetailDataArray = [listElement elementsForName:@"OrderDetailData"]; 

     int count = 0; 
     for (GDataXMLElement *orderDetailDataElement in orderDetailDataArray) { 

      NSString *attributeForOrderDetailDataElement = [(GDataXMLElement *) [orderDetailDataElement attributeForName:@"HASH"] stringValue]; 

      NSLog(@"attributeForOrderDetailDataElement has value %@", attributeForOrderDetailDataElement); 

      count++; 
     } 

     NSLog(@"%d", count); 
    } 
} 

[doc release]; 
[xmlData release]; 

這是輸出控制檯：

attributeForOrderDataElement has value 208524692 <-- HASH value 
id has value 97 <-- id value 
attributeForOrderDetailDataElement has value 516790072 <-- HASH value 
attributeForOrderDetailDataElement has value 11226247 
attributeForOrderDetailDataElement has value 11226247 
3 <-- the count 

希望它能幫助。

編輯

test2.xml包含您的文件，但你可以把它作爲一個字符串。您還可以作爲參數傳遞像串如下：

NSString* xmlString = @"<list>" 
    "<OrderData HASH=\"1408108039\"></OrderData>" 
    "<OrderData HASH=\"208524692\">" 
    "<id>97</id>" 
    "<customer>" 
    "<CustomerData HASH=\"2128670187\"></CustomerData>" 
    "</customer>" 
    "<billingAddress></billingAddress>" 
    "<deliveryAddress></deliveryAddress>" 
    "<orderDetail>" 
    "<list>" 
    "<OrderDetailData HASH=\"516790072\"></OrderDetailData>" 
    "<OrderDetailData HASH=\"11226247\"></OrderDetailData>" 
    "<OrderDetailData HASH=\"11226247\"></OrderDetailData>" 
    "</list>" 
    "</orderDetail>" 
    "<log/>" 
    "</OrderData>" 
    "<OrderData HASH=\"1502226778\"></OrderData>" 
    "</list>";  

GDataXMLDocument *doc = [[GDataXMLDocument alloc] initWithXMLString:xmlString options:0 error:&error]; 

Answer 2

如果OrderDetailData存在於陣列的第二對象中的所有時間，u可以使用下面的

NSArray* arr = [[XMLelement elementForName:@"list"] elementsForName:@"OrderData"];  
NSXMLElement* listElement = [[[arr objectAtIndex:1] elementForName:@"orderDetail"] elementForName:@"list"]; 
NSArray* orderDetailArray* = [listElement elementsForName:@"OrderDetailData"]; 

在此u能獲得陣列中的OrderDetailData元件，和u可以解析在循環中的數據。獲得HASH值的使用。

NSString* hash = [[orderDetailArray objectAtIndex:0] stringValueForAttribute:@"HASH"]; 

Answer 3

我發現TouchXML容易解析，您可以直接訪問從XML

首先下載TouchXML的需要的數據和框架添加libxml2.dylib到項目中。 變化buildsetting的 「頭文件搜索路徑」，添加 「/ usr/include目錄/ libxml2的」 導入TouchXML.h到您的文件

//Access document 
CXMLDocument *parserDoc = [[CXMLDocument alloc] initWithContentsOfURL:url options:0 error:&err]; 

//Access root element and access children in heirarchy 
CXMLElement *root = [parserDoc rootElement]; 
NSArray *places = [[[root children] objectAtIndex:0] children]; 

否則

//Access node by node 
NSString *location =[[[[[parserDoc nodesForXPath:@"/xml_api_reply/weather/forecast_information/city" error:nil] objectAtIndex:0] attributeForName:@"data"] stringValue] retain]; 

Answer 4

這是下面的代碼，我努力了。我得到了正確的輸出..檢查出

NSString* xmlString = @"<?xml version=\"1.0\" encoding=\"UTF-8\"?>" 
         "<list>" 
         "<OrderData HASH=\"1408108039\"></OrderData>" 
         "<OrderData HASH=\"208524692\">" 
         "<id>97</id>" 
         "<customer>" 
         "<CustomerData HASH=\"2128670187\"></CustomerData></customer>" 
         "<billingAddress></billingAddress><deliveryAddress></deliveryAddress>" 
         "<orderDetail>" 
         "<list>" 
         "<OrderDetailData HASH=\"516790072\"></OrderDetailData>" 
         "<OrderDetailData HASH=\"11226247\"></OrderDetailData>" 
         "<OrderDetailData HASH=\"11226247\"></OrderDetailData>" 
         "</list>" 
         "</orderDetail>" 
         "<log/></OrderData>" 
         "<OrderData HASH=\"1502226778\"></OrderData>" 
         "</list>"; 

NSXMLDocument* doc = [[NSXMLDocument alloc] initWithData:[xmlString dataUsingEncoding:NSUTF8StringEncoding] options:0 error:nil]; 
NSXMLElement* rootElement = [doc rootElement]; 

NSArray* arr = [rootElement elementsForName:@"OrderData"]; 
NSXMLElement* orderDataElement; 

for (int i = 0; i < [arr count]; i++) 
{ 
    int Id = 0; 
    Id = [[arr objectAtIndex:i] integerValueForNode:@"id"]; 
    if (Id != 0) 
    { 
     orderDataElement = [arr objectAtIndex:i]; 
     break; 
    } 
} 

NSArray* orderDetailArray = [[[orderDataElement elementForName:@"orderDetail"] 
           elementForName:@"list"] 
          elementsForName:@"OrderDetailData"]; 

for (int j = 0; j < [orderDetailArray count]; j++) 
{ 
    NSLog(@"%@", [[orderDetailArray objectAtIndex:j] stringValueForAttribute:@"HASH"]); 
}