从数据库填充 Spinner 时的奇怪行为

Question

我正在尝试从 Mysql 数据库到 JSON 填充微调器。问题是数据导出正常。但是，当我单击 Spinner 以显示下拉菜单时，应用程序崩溃了。

数据库的JSON输出：Output

错误：

03-01 18:12:42.966    3214-3214/com.order.app.order E/ArrayAdapter﹕ You must supply a resource ID for a TextView
03-01 18:12:42.966    3214-3214/com.order.app.order D/AndroidRuntime﹕ Shutting down VM
03-01 18:12:42.967    3214-3214/com.order.app.order E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.order.app.order, PID: 3214
    java.lang.IllegalStateException: ArrayAdapter requires the resource ID to be a TextView
            at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:386)
            at android.widget.ArrayAdapter.getDropDownView(ArrayAdapter.java:415)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.widget.TextView
            at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:379)
            at android.widget.ArrayAdapter.getDropDownView(ArrayAdapter.java:415)

我的适配器：

public class SpiritsListAdapter extends ArrayAdapter<SpiritList> {

    public SpiritsListAdapter(Context context, int layoutId, List<SpiritList> items) {
        super(context, layoutId, items);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        SpiritHolderItems holder;

        if(convertView == null){
            LayoutInflater vi;
            vi = LayoutInflater.from(getContext());
            convertView = vi.inflate(R.layout.spinner_item, parent, false);

            holder = new SpiritHolderItems();
            holder.spiritName = (TextView)convertView.findViewById(R.id.spirit_name);
            holder.spiritPrice = (TextView)convertView.findViewById(R.id.spirit_price);
            convertView.setTag(holder);
        }else{
            holder = (SpiritHolderItems) convertView.getTag();
        }
            SpiritList current = getItem(position);
            holder.spiritName.setText(current.getName());
            holder.spiritPrice.setText(current.getPrice() + " €");
        return convertView;
    }

    static class SpiritHolderItems {
        TextView spiritName, spiritPrice;
    }
}

我的异步任务：

public class JsonReadTask extends AsyncTask<String , Void, List<SpiritList>> {
        public JsonReadTask() {
            super();
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(Gins.this, ProgressDialog.THEME_DEVICE_DEFAULT_DARK);
            pDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
            pDialog.setIndeterminate(true);
            pDialog.setMessage(getString(R.string.get_stocks));
            pDialog.setCancelable(false);
            pDialog.setInverseBackgroundForced(true);
            pDialog.show();
        }

        @Override
        protected List<SpiritList> doInBackground(String... params) {
            HttpClient httpclient = new DefaultHttpClient();
            HttpPost httppost = new HttpPost(params[0]);
            try {
                HttpResponse response = httpclient.execute(httppost);
                jsonResult = inputStreamToString(
                        response.getEntity().getContent()).toString();
                customList = new ArrayList<>();

                JSONObject jsonResponse = new JSONObject(jsonResult);
                JSONArray jsonMainNode = jsonResponse.optJSONArray("gins");
                for (int i = 0; i < jsonMainNode.length(); i++) {
                    JSONObject jsonChildNode = jsonMainNode.getJSONObject(i);
                    String name = jsonChildNode.optString("name");
                    String price = jsonChildNode.optString("price");
                    customList.add(new SpiritList(name, price));
                }
                return customList;
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }

        private StringBuilder inputStreamToString(InputStream is) {
            String rLine = "";
            StringBuilder answer = new StringBuilder();
            BufferedReader rd = new BufferedReader(new InputStreamReader(is));
            try {
                while ((rLine = rd.readLine()) != null) {
                    answer.append(rLine);
                }
            } catch (Exception e) {
                throw new RuntimeException(e.getMessage());
            }
            return answer;
        }

        @Override
        protected void onPostExecute(List<SpiritList> customList) {
            if(customList == null){
                Log.d("ERORR", "No result to show.");
                return;
            }
            ListDrawer(customList);
            pDialog.dismiss();
        }
    }// end async task

    public void accessWebService() {
        JsonReadTask task = new JsonReadTask();
        task.execute(new String[]{url});
    }

    public void ListDrawer(List<SpiritList> customList) {
        adapterGins = new SpiritsListAdapter(getApplicationContext(), R.layout.spinner_item, customList);
        adapterGins.notifyDataSetChanged();
        spDrinks.setAdapter(adapterGins);
        Log.d("Spinner Count", "The Spinner count is " + spDrinks.getCount());
    }

我的布局如下：

知道为什么会这样吗？我正在膨胀自定义布局，但它把它当作 ArrayAdapter<String>.

Answer 1

您正在 this page 上使用第五个构造函数列表，这要求您的第二个参数是

The resource ID for a layout file containing a TextView to use when instantiating views.

你还没有包含你的 xml，R.layout.spinner_item 里面有 TextView 吗？

你的堆栈跟踪中有 ArrayAdapter 因为你的 SpiritsListAdapter 扩展了 ArrayAdapter，所以每次你调用 super() 或 ArrayAdapter 之一调用您未覆盖的方法，使用 ArrayAdapter class 中的代码。

编辑：您是否尝试过使用此构造函数：ArrayAdapter(Context context, int resource, int textViewResourceId, List<T> objects)（它是上面链接页面上的第六个构造函数），并在其中给它提供要填充的 TextView 的 ID？布局中有两个 TextView 可能会导致问题（如评论中所述）。

Answer 2

您可以使用 BaseAdapter 做同样的事情：

public class SpiritsListAdapter extends BaseAdapter

像这样修改你的构造函数：

    private List<SpiritList> objects;
    private Context context;

    public SpiritsListAdapter(Context context ,List<SpiritList> objects) {
        this.context = context;
        this.objects = objects;
    }

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

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

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

并添加未实现的方法，并保持 getView 方法不变。

希望对您有所帮助！！！

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