从数据库填充Spinner时的奇怪行为

Question

I am trying to populate a spinner from Mysql Databse through JSON. The thing is that the data are exported fine. But when I click the Spinner to show the dropdown menu the app crashes.

The JSON output from database: Output

The Error:

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)

My Adapter:

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;
    }
}

My AsyncTask:

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());
    }

My Layout looks like:

Any ideas why is this happening? I am inflating the custom layout and yet it takes it as an ArrayAdapter<String> .

Answer 1

You're using the fifth constructor list on this page , which requires that your second parameter be

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

You haven't included your xml, does R.layout.spinner_item have a TextView in it?

Your stacktrace has ArrayAdapter in it because your SpiritsListAdapter extends ArrayAdapter , so every time you call super() or one of the ArrayAdapter 's methods that you haven't overriden is called, code from the ArrayAdapter class is used.

Edit: Have you tried using this constuctor: ArrayAdapter(Context context, int resource, int textViewResourceId, List<T> objects) (it's the sixth one on the page linked to above) where you give it the id of the TextView you want to populate? There could be a problem caused by having two TextView s in the layout (as noted in the comments).

Answer 2

You can do the same thing using BaseAdapter as such:

public class SpiritsListAdapter extends BaseAdapter

Modify your constructor like this:

    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;
    }

and add the unimplemented methods and you keep your getView method as it is.

Hope it helps!!!