页面加载不出来listview

 for (int i = 0; i < 20; i++) {
            HashMap<String, String> map = new HashMap<String, String>();
            map.put("carbrand", "奥迪A4");
            map.put("models", "14款 40 TFSl allroad quattro lius");
            map.put("mark_price", "46.98万");
            map.put("price", "36.17万");
            map.put("user", "经销商名字");
            map.put("province", "湖南");
            map.put("area", "开福区");
            data_car.add(map);
        }

换成Json后，就显示不出来了，但是本人数据都获取到了。另外一个fragment一模一样的写法都可以正常显示，这个fragment无论怎么样都加载不出来！

 x.http().post(requestParams, new Callback.CommonCallback<String>() {
            @Override
            public void onSuccess(String result) {
                LogOut(result,TAG);
                try {
                    JSONObject jsonObject = new JSONObject(result);
                    int code = jsonObject.getInt("code");
                    if (code == 1) {
                        CommTools.showToast(jsonObject.getString("success"));
                        // jsonObject= jsonObject.getJSONObject("data");
                        JSONArray jsonArray = jsonObject.getJSONArray("data");
                        for (int i = 0; i < jsonArray.length(); i++) {
                            HashMap<String, String> map = new HashMap<String, String>();
                            JSONObject item = jsonArray.getJSONObject(i); 
                            String carbrand = item.getString("carbrand");
                            String models = item.getString("models");
                            String mark_price = item.getString("mark_price");
                            String price = item.getString("price");
                            String area = item.getString("area");
                            String province = item.getString("province");
                            String user = item.getString("user");
                            map.put("carbrand",carbrand);
                            map.put("models",models);
                            map.put("mark_price",mark_price);
                            map.put("price",price);
                            map.put("area",area);
                            map.put("province",province);
                            map.put("user",user);
                            data_car.add(map);
                        }
                    }else {
                        CommTools.showToast(jsonObject.getString("success"));
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
            @Override
            public void onError(Throwable ex, boolean isOnCallback) {
            }
            @Override
            public void onCancelled(CancelledException cex) {
            }
            @Override
            public void onFinished() {
            }
        });
 SimpleAdapter simple_car = new SimpleAdapter(App.getInstance(),
                data_car,
                R.layout.item_car,
                new String[]{"carbrand","models","mark_price","price","user","province","area"},
                new int[]{R.id.tv_carbrand, R.id.tv_carintro, R.id.tv_carzhidao, R.id.tv_carprice, R.id.tv_jsxname,R.id.tv_jsxlocal,R.id.tv_jxsarea});
        carListView.setAdapter(simple_car);

一直解不出来，本人真的毫无头绪！