Текста не устанавливая в Baseadapter

Question

Я следую this примеру реализация EndlessScrolllistview, когда я запускаю мое приложение приложение получило аварию и дает следующие ошибки, любая помощь будет признательна, спасибо

Это мой класс адаптера

public class EndlessAdapter extends BaseAdapter { 

    //private List<String> itemList; 
    private Context ctx; 
    private int layoutId; 


    private ArrayList<HashMap<String, String>> listData; 
    //private AQuery aQuery; 
    String rup = "\u20B9"; 
    //private ArrayList<String> usersizesArrayList; 

    private static final String TAG_NAME = "name"; 
    private static final String TAG_IMAGE = "img_url"; 
    private static final String TAG_PRICE = "price"; 
    private static final String TAG_ID_PRODUCT = "id_product"; 
    /*public EndlessAdapter(Context ctx, List<String> itemList, int layoutId) { 
     super(ctx, layoutId, itemList); 
     this.itemList = itemList; 
     this.ctx = ctx; 
     this.layoutId = layoutId; 
    }*/ 

    public EndlessAdapter(Context ctx, ArrayList<HashMap<String, String>> listData) { 
     this.ctx = ctx; 
     this.listData = listData; 
     //aQuery = new AQuery(this.context); 
    } 

    @Override 
    public int getCount() {  
     return listData.size() ; 
    } 

    @Override 
    public Object getItem(int position) { 
     return listData.get(position); 
    } 

    @Override 
    public long getItemId(int position) {  
     return position; 
    } 

    /*@Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     View result = convertView; 

     if (result == null) { 
      LayoutInflater inflater = (LayoutInflater) ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
      result = inflater.inflate(layoutId, parent, false); 
     } 

     // We should use class holder pattern 
     TextView tv = (TextView) result.findViewById(R.id.txt1); 
     //tv.setText(itemList.get(position)); 
     */ 

    @Override 
    public View getView(final int position, View convertView, ViewGroup parent) { 
     final ViewHolder holder; 
     if (convertView == null) { 
      holder = new ViewHolder(); 

      convertView = LayoutInflater.from(ctx).inflate(R.layout.row_layout, null); 
      holder.txtproname = (TextView) convertView.findViewById(R.id.txt1); 

     } else { 
      holder = (ViewHolder) convertView.getTag(); 
     } 

     holder.txtproname.setText(listData.get(position).get(TAG_NAME)); 
     return convertView; 

    } 
    class ViewHolder { 
     public EditText qunatityss; 
     public TextView bordrsfourth; 
     public TextView bordrsthird; 
     public TextView bordrssecond; 
     public TextView bordrs; 
     public RadioButton productsizesmall; 
     public RadioButton productsizemed; 
     public RadioButton productsizelarge; 
     public RadioButton productsizexlarge; 
     public TextView fourthcolor; 
     public TextView thirdcolor; 
     public TextView secondcolor; 
     public ImageView cartview; 
     TextView txtprice; 
     ImageView propic; 
     TextView txtproname; 
     TextView firstcolor; 
     Button addtocart; 
    } 

Ошибка

12-31 12:43:52.611: E/AndroidRuntime(6029): FATAL EXCEPTION: main 
12-31 12:43:52.611: E/AndroidRuntime(6029): java.lang.NullPointerException 
12-31 12:43:52.611: E/AndroidRuntime(6029):  at com.survivingwithandroid.endlessadapter.EndlessAdapter.getView(EndlessAdapter.java:109) 

номер строки 109

holder.txtproname.setText(listData.get(position).get(TAG_NAME)); 

Может ли кто-нибудь помочь?

Answer 1

Вам не нужно, чтобы объявить объект держателя в качестве окончательного.

public View getView(int position, View convertView, ViewGroup parent) { 

    ViewHolder holder; 

    if (convertView == null) { 

     convertView = LayoutInflater.from(ctx).inflate(R.layout.row_layout, null); 

     holder = new ViewHolder(); 

     holder.txtproname = (TextView) convertView.findViewById(R.id.txt1); 

     convertView.setTag(holder); 

    } 

    else { 

     holder = (ViewHolder) convertView.getTag(); 

    } 

} 

Answer 2

вам нужно использовать setTag() в if состоянии

if (convertView == null) { 
     holder = new ViewHolder(); 

     convertView = LayoutInflater.from(ctx).inflate(R.layout.row_layout, null); 
     holder.txtproname = (TextView) convertView.findViewById(R.id.txt1); 

     convertView.setTag(holder); 

    }