Get the list of values using dom parser in android

Question

I have to develop an android application.

Here i have follows following xml format.

<Product>
<product name="viki" productid="111">
<ProductType>
<producttype>Nokia</producttype>
<producttype>Samsung</producttype>
</ProductType>
</product>
</Product>

Here i have to get the producttype for particluar product.so i have wrote the following code:

    if(subCategoryChildNode.hasChildNodes()){
            // parse 'Subcategory' childs
        NodeList productNL = subCategoryChildElmt.getElementsByTagName("product");
        if(productNL.getLength() > 0){

        ArrayList<Product> productAL = new ArrayList<Product>();
        Product productBean = null;
        for(int pCnt=0;pCnt<productNL.getLength();pCnt++){
            Node productNode = productNL.item(pCnt);

            Element productElmt = null;
            // parse 'product' tag attributes 
            if(productNode.hasAttributes()){
                productBean = new Product();
                productElmt = (Element)productNode;
                productBean.setmProductName(productElmt.getAttribute("name"));
            }
            if(productNode.hasChildNodes()){
                NodeList productTypeNL = productElmt.getElementsByTagName("ProductType");
                if(productTypeNL.getLength() > 0){
                    ArrayList<ProductType> ProductTypeAL = new ArrayList<ProductType>();
                    ProductType productTypeBean = null;
                    for(int ptCnt=0;ptCnt<productTypeNL.getLength();ptCnt++){
                    Node productTypeNode = productTypeNL.item(ptCnt);
                    Element productTypeElmt = null;
                    if(productTypeNode.hasChildNodes()){
                        productTypeBean = new ProductType();
                        productTypeElmt = (Element)productTypeNode;
                        productTypeBean.setmProductType(XMLfunctions.getValue(productTypeElmt,"producttype"));
                        System.out.println("Product Types are "+ " "+XMLfunctions.getValue(productTypeElmt,"producttype"));
                        ProductTypeAL.add(productTypeBean);
                    }
                    productBean.setmProductTypes(ProductTypeAL);
                    }
                productAL.add(productBean);
                }
            }
            subCategoryBean.setmProducts(productAL);
        }
        }
    subCategoryAL.add(subCategoryBean);
}

Here am getting the value is nokia alone.but i need to display the value nokia,samsung...if i have to run the app means getting single value.but i need to get the list of all values..

What's wrong in my code .. please check and give me solution fot these ???

Answer 1

The reason you're getting only one <producttype> (Nokia) instead of the complete list because you're looping over the length of <ProductType> nodes thinking you're looping over the <producttype> ones.

So, you need another inner loop to cover all the child product type nodes like

for(int ptCnt=0; ptCnt < productTypeNL.getLength(); ptCnt++) {
    Node productTypeNode = productTypeNL.item(ptCnt);
    if(productTypeNode.hasChildNodes()){
        NodeList childProductTypeNL = productTypeNode.getChildNodes();
        System.out.print("Product Types are: ");
        for (int cptCnt=0; cptCnt < childProductTypeNL.getLength(); cptCnt++) {
            productTypeBean = new ProductType();
            productTypeBean.setmProductType (
                            childProductTypeNL.item(cptCnt).getTextContent());
            System.out.print(productTypeBean.getmProductType() + ", ");
            ProductTypeAL.add(productTypeBean);
        }
    }
    productBean.setmProductTypes(ProductTypeAL);
}

I've directly used the Node.getChildNodes() and Node.getTextContexnt() methods, instead of type casting to Element first and using its methods or the XMLfunctions utility class.

I also recommend using different names for child nodes instead of relying on using a different case to avoid such problems in future. A simple way to avoid name collision (when you're not able to come up with a different name) is to simply use a plural like <ProductTypes> for the parent tag.

However, a better approach when you need to parse deep within a DOM tree is to use an XPath to directly get the list of nodes you're interested in. I'm not entirely sure what the program does but just to give you an example an XPath like

 String xpath = "//product[@name=\"viki\"]/ProductType/producttype";

would give you the NodeList for <producttype> nodes directly.

Answer 2

I'd say one of the problem of your code (might be others), is that you declare your productTypeBean and productTypeElmt before your for loop, and since it's not required after, it isn't needed.

if(subCategoryChildNode.hasChildNodes()){
        // parse 'Subcategory' childs
    NodeList productNL = subCategoryChildElmt.getElementsByTagName("product");
    if(productNL.getLength() > 0){
        ArrayList<Product> productAL = new ArrayList<Product>();
        Product productBean = null;
        for(int pCnt=0;pCnt<productNL.getLength();pCnt++){
            Node productNode = productNL.item(pCnt);

            Element productElmt = null;
            // parse 'product' tag attributes 
            if(productNode.hasAttributes()){
                productBean = new Product();
                productElmt = (Element)productNode;
                productBean.setmProductName(productElmt.getAttribute("name"));
            }
            if(productNode.hasChildNodes()){
                NodeList productTypeNL = productElmt.getElementsByTagName("ProductType");
                if(productTypeNL.getLength() > 0){
                    ArrayList<ProductType> ProductTypeAL = new ArrayList<ProductType>();
                    for(int ptCnt=0;ptCnt<productTypeNL.getLength();ptCnt++){
                        Node productTypeNode = productTypeNL.item(ptCnt);
                        if(productTypeNode.hasChildNodes()){
                            ProductType productTypeBean = new ProductType();
                            Element productTypeElmt = (Element)productTypeNode;
                            productTypeBean.setmProductType(XMLfunctions.getValue(productTypeElmt,"producttype"));
                            System.out.println("Product Types are "+ " "+XMLfunctions.getValue(productTypeElmt,"producttype"));
                            ProductTypeAL.add(productTypeBean);
                        }
                        productBean.setmProductTypes(ProductTypeAL);
                    }
                    productAL.add(productBean);
                }
            }
            subCategoryBean.setmProducts(productAL);
        }
    }
    subCategoryAL.add(subCategoryBean);
}