HttpConnection黑莓8900

Question

我是个黑莓新手，我用黑莓9800模拟器创建了一个HTTP连接。我写了下面的代码。

    public MyScreen()
{        
    // Set the displayed title of the screen       
    setTitle("Hello");
    ConnectionFactory connFact = new ConnectionFactory();
    ConnectionDescriptor connDesc;
    connDesc = connFact.getConnection("http://whistlersbest.net/api/categories.php?parent_id=0");
    System.out.println("hello " + connFact);
    if (connDesc != null)
    {
        HttpConnection httpConn;
        httpConn = (HttpConnection)connDesc.getConnection();
        try
        {
            in = httpConn.openInputStream();

            int ii;
            while((ii=in.read()) != -1){

              strbuffer = strbuffer + (char)ii;
            }
         } 
         catch (IOException e) 
         {
           System.err.println("Caught IOException: " 
                + e.getMessage());
         }
    }
    setTitle("Whistlers Best");
    System.out.println("set Title");
    xmlHandler xm = new xmlHandler(strbuffer);
    category = xm.getCategory();
    System.out.println("category set");
    String[] arr = new String[category.getIds().size()];
    System.out.println("Array " + arr.length);
    list = new ObjectListField(){
        protected boolean navigationClick(int status, int time) {
            //UiApplication.getUiApplication().pushScreen(new SubCategories(category.getIds().elementAt(list.getSelectedIndex()).toString(),"1",category.getNames().elementAt(list.getSelectedIndex()).toString()));
            return false;

        }

    };
    for(int y = 0; y<category.getIds().size() ; y++){
        arr[y] = (String)category.getNames().elementAt(y);
        System.out.println("string: "+arr[y]);
    }


    list.set(arr);
    VerticalFieldManager hfm = new VerticalFieldManager(Manager.FIELD_HCENTER);
    hfm.add(new LabelField("Categories",
            Field.FIELD_HCENTER));
    hfm.add(list);
    list.setChangeListener(this);
    add(hfm);

}

它工作得很完美。但是突然我需要从Blackberry 9800切换到Blackberry 8900 Curve。我使用模拟器，并编写相同的代码。但是我让NullPointerException在线上：

connDesc = connFact.getConnection("http://whistlersbest.net/api/categories.php?parent_id=0");

我哪里错了？

Answer 1

5版本以后支持ConnectionFactory.getConnection()，黑莓8900是5.x还是4.x？我想是4.x。

你可以试试这个：HTTPConnection httpConnector = (HttpConnection) Connector.open(url);

并获得响应：httpConnector.setRequestMethod(HttpConnection.GET); InputStream in = httpConnector.openInputStream();