listView的适配器Adapter不响应解决思路

listView的适配器Adapter不响应
Java code

            ListView listView = (ListView) findViewById(R.id.listview);
            Log.d("LC", "解析成功");
            listView.setAdapter(new ListViewAdapter(this));
            Log.d("LC", "解析成功2");

private class ListViewAdapter extends BaseAdapter {

        private LayoutInflater mInflater;
        private Context mContext;
        
        public ListViewAdapter(Context ctx) {
            this.mContext = ctx;
            this.mInflater = LayoutInflater.from(ctx);
            Log.d("LC", "进入");
        }
        
        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            Log.d("LC", "进入2");
            return weatherList.size();
        }
  
        @Override
        public Object getItem(int arg0) {
            // TODO Auto-generated method stub
            return null;
        }

        @Override
        public long getItemId(int arg0) {
            // TODO Auto-generated method stub
            return arg0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup arg2) {
            Log.d("LC", "进入3");
            ListViewHolder viewHolder;
            if(convertView == null) {
                convertView = mInflater.inflate(R.layout.listitem, null);
                viewHolder = new ListViewHolder();
                viewHolder.imageViewIcon = (ImageView)convertView.findViewById(R.id.image_item);
                viewHolder.day = (TextView)convertView.findViewById(R.id.text_item_1);
                viewHolder.temp = (TextView)convertView.findViewById(R.id.text_item_2);
                viewHolder.condition = (TextView)convertView.findViewById(R.id.text_item_3);
                convertView.setTag(viewHolder);
        //        viewHolder.btnDownLoad.setTag(viewHolder);
            }else {
                viewHolder = (ListViewHolder)convertView.getTag();
            }
        

        
            for(Weather weather : weatherList){
                Log.d("LC", "weatherList:"+weather.getDay());
                Log.d("LC", "weatherList:"+weather.getHighTemp());
                Log.d("LC", "weatherList:"+weather.getLowTemp());
                Log.d("LC", "weatherList:"+weather.getCondition());
                Log.d("LC", "下一天");                 
           }
            
    
            return convertView;
        }
        



我设置的ListView控件来获取网络上的信息,都已经能够获得准确数据,但是,list的适配器不响应啊,为什么?
把最后一段输出的测试代码放在适配器的构造函数中,可以执行,但是,就是不执行public int getCount(),没有输出测试的信息 ,那后边的getView更不可能执行了啊!
各位,请问是什么可能的原因导致了这个适配器的无效呢?

------解决方案--------------------
weatherList是哪里的,全局变量吗。为什么getItem要return一个null,我擦,这代码写的非常有高度啊。一般人真看不懂。
------解决方案--------------------
public int getCount() {}//获取项目的条数
public Object getItem(int arg0) {}//获取每条项目的项目
public long getItemId(int arg0) {}//获取每条项目的ID
这三个方法都是在进行页面初始化的时候有系统调用,你没什么都没写,系统怎么按你的要求生成相应的视图!另外你的weatherList应该是全局变量!好好看看网上关于上面三个方法的讲解!
------解决方案--------------------
listView.setAdapter(new ListViewAdapter(this));
 可以试试把this补全了 前面加上类名