Question

我在ListView中收到的值无效。我的代码如下。

 final ArrayList<HashMap<String, String>> placesListItems = new ArrayList<HashMap<String, String>>();

        runOnUiThread(new Runnable() {
            public void run() {
                try {
                    HashMap<String, String> map = new HashMap<String, String>();

                    for (int i = 0; i < dealList.size(); i++) {
                        map.put(DealItem.DEAL_ID, dealList.get(i).deal_id);
                        map.put(DealItem.DEAL_NAME, dealList.get(i).deal_name);
                        System.out.println("DEAL NAME = "+dealList.get(i).deal_name);
                        placesListItems.add(map);

                    }

                    new PlacesMapActivity(SinglePlaceActivity.this, lon, lat, name, add);

                    ListView lv = (ListView) findViewById(R.id.listView);
                    simpleAdapter = new SimpleAdapter(SinglePlaceActivity.this, placesListItems, R.layout.list_item_deal, new String[] {
                            DealItem.DEAL_ID, DealItem.DEAL_NAME }, new int[] { R.id.reference, R.id.name });
                    lv.setAdapter(simpleAdapter);

当我运行此代码时，我得到这样的答案

  10-03 18:37:29.429: I/System.out(3957): DEAL NAME = Sinbad Cafe
  10-03 18:37:52.369: I/System.out(3957): DEAL NAME = Coffee,Tea, Hot Milk
  10-03 18:37:55.189: I/System.out(3957): DEAL NAME = Httpss

但我不明白为什么我在ListView

中收到无效值

如下所示：

  Httpss
  Httpss
  Httpss

Answer 1

相同的地图会多次添加到列表中。

尝试将新的HashMap＆lt; ...＆gt; -line移动到for循环中：

                for (int i = 0; i < dealList.size(); i++) {
         -->        HashMap<String, String> map = new HashMap<String, String>();
                    map.put(DealItem.DEAL_ID, dealList.get(i).deal_id);
                    map.put(DealItem.DEAL_NAME, dealList.get(i).deal_name);
                    System.out.println("DEAL NAME = "+dealList.get(i).deal_name);
                    placesListItems.add(map);

                }

Answer 2

   +-------- HashMap<String, String> map = new HashMap<String, String>();
   |
   |            for (int i = 0; i < dealList.size(); i++) {
   +--------------->  
                    map.put(DealItem.DEAL_ID, dealList.get(i).deal_id);
                    map.put(DealItem.DEAL_NAME, dealList.get(i).deal_name);
                    System.out.println("DEAL NAME = "+dealList.get(i).deal_name);
                    placesListItems.add(map);

                }

由于您在循环外部进行了“HashMap”初始化，因此实际上是在覆盖相同的散列映射并将其放回到arraylist中。

尝试在for-loop中移动你的HashMap初始化。

Answer 3

使用以下代码更改代码，它将解决您的错误.....

    try {


                for (int i = 0; i < dealList.size(); i++) {
                 HashMap<String, String> map = new HashMap<String, String>();
                    map.put(DealItem.DEAL_ID, dealList.get(i).deal_id);
                    map.put(DealItem.DEAL_NAME, dealList.get(i).deal_name);
                    System.out.println("DEAL NAME = "+dealList.get(i).deal_name);
                    placesListItems.add(map);

      }

从ArrayList <hashmap <string，string =“”>＆gt; </hashmap <string，>得到无效值

3 个答案: