Question

我从网上获得了String t 作为Json并解析了它。然后我使用SimpleAdapter添加我在ListView.But上运行的数据，我遇到了问题listView有时消失，有时出现成功。为什么会发生这种情况？

private void parseData(String t){
                // TODO Auto-generated method stub
                try {
                        JSONObject jsonObject = new JSONObject(t);
                        JSONArray datas = (JSONArray)jsonObject.getJSONArray("datas");
                        HashMap<String, String> item;
                        for(int i = 0;i<datas.length();i++){
                            JSONObject info = (JSONObject)datas.getJSONObject(i);
                            String number = info.getString("number");
                            String stocktakingTime = info.getString("stocktakingTime");
                            JSONObject category = info.getJSONObject("category");
                            String text = category.getString("text");
                                item = new HashMap<String, String>();
                                item.put("number", number);
                                item.put("stocktakingTime", stocktakingTime);
                                item.put("text",text);  
                                goodsList.add(item);
                        }

                    } catch (Exception e) {
                        e.printStackTrace();
                    }
            }       


public void initWidget() {
    SimpleAdapter adapter = new SimpleAdapter(this, goodsList,
            R.layout.check_task_list_view, new String[] {
                    "number", "stocktakingTime", "text" },
            new int[] { R.id.checkNumber, R.id.stocktakingTime,
                    R.id.checkText});
    listView = new ListView(this);
    listView.setAdapter(adapter);
    listView.setPadding(10, 10, 10, 10);
    listView.setOnItemClickListener(new OnItemClickListener(){

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            // TODO Auto-generated method stub

            switch (position) {
            case 0:
                Intent it = new Intent(CheckTaskActivity.this,CheckTaskCustomSellerActivity.class);
                startActivity(it);
                break;
            case 1:
                Intent it1 = new Intent(CheckTaskActivity.this,CheckTaskCustomSellerActivity.class);
                startActivity(it1);
                break;


            default:
                break;
            }

        }

    });

    LinearLayout checkTaskList = (LinearLayout) findViewById(R.id.checkTaskList);
    checkTaskList.addView(listView);
    bindListener();
}

Answer 1

在哪里找到＆＃34; goodsList＆＃34;变量？它是创建表单的列表变量哈希地图(List<? extends Map<String, ?>> item )

然后你犯了一个错误以下代码

for(int i = 0;i<datas.length();i++){
                        JSONObject info = (JSONObject)datas.getJSONObject(i);
                        String number = info.getString("number");
                        String stocktakingTime = info.getString("stocktakingTime");
                        JSONObject category = info.getJSONObject("category");
                        String text = category.getString("text");
                            item = new HashMap<String, String>();
                            item.put("number", number);
                            item.put("stocktakingTime", stocktakingTime);
                            item.put("text",text);  
                            goodsList.add(item);
                    }

每次for循环运行时都会初始化项变量那么只有一个项目可以包含hasmap。

做到.....................

HashMap<String, String> item = new HashMap<String, String>();
                        for(int i = 0;i<datas.length();i++){
                            JSONObject info = (JSONObject)datas.getJSONObject(i);
                            String number = info.getString("number");
                            String stocktakingTime = info.getString("stocktakingTime");
                            JSONObject category = info.getJSONObject("category");
                            String text = category.getString("text");

                                item.put("number", number);
                                item.put("stocktakingTime", stocktakingTime);
                                item.put("text",text);  
                                goodsList.add(item);
                        }

Answer 2

JSONArray数据可能为空，因此您无法填充goodsList，然后listview没有项目所以请检查数据JSONArray

当我使用简单的适配器时，为什么每次都不会出现listview？

2 个答案: