Custom Adapter getView() method is not called

问题

Here is the code of the fragment in which I am setting a custom adapter to the list.

There no errors but the ListView is empty. I have implemented getCount() which returns right number of items in my ArrayList. I don\'t see (\"Inside\", \"GetView\") in the logcat

Fragment

public class ServiceCarListFragment extends Fragment {

    private String url;
    private ArrayList<CarDetail> carDetailList = new ArrayList<CarDetail>();
    private CarListAdapter adapter;
    private ListView mList;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        url = getActivity().getIntent().getStringExtra(\"url\");
        new DownloadCarDetail().execute(url);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        View v = inflater.inflate(R.layout.fragment_service_car_list, container, false);
        mList = (ListView) v.findViewById(R.id.list);
        mList.setAdapter(adapter);

        for (CarDetail car : carDetailList) {
            // START LOADING IMAGES FOR EACH STUDENT
            car.loadImage(adapter);
        }
        return v;
    }

    class DownloadCarDetail extends AsyncTask<String, String, ArrayList<CarDetail>> {

        @Override
        protected ArrayList<CarDetail> doInBackground(String... params) {
            // TODO Auto-generated method stub
            ArrayList<CarDetail> carDetailList = JsonParser.parseJson(params[0]);
            return carDetailList;
        }

        @Override
        protected void onPostExecute(ArrayList<CarDetail> carDetailList) {
            // TODO Auto-generated method stub
            ServiceCarListFragment.this.carDetailList = carDetailList;
            Log.d(\"dccs\", String.valueOf(ServiceCarListFragment.this.carDetailList.size()));
            adapter = new CarListAdapter(getActivity(), ServiceCarListFragment.this.carDetailList);
            Log.d(\"dccs\", String.valueOf((adapter.getCount())));
        }

    }
}

CustomAdapter

public class CarListAdapter extends BaseAdapter {

    private ArrayList<CarDetail> items = new ArrayList<CarDetail>();
    private Context context;

    public CarListAdapter(Context context, ArrayList<CarDetail> items) {
        this.context = context;
        this.items = items;
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return items.size();
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return items.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        Log.d(\"Inside\", \"GetView\");
        LayoutInflater mInflater = (LayoutInflater) context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        ViewHolder holder = null;
        CarDetail car = items.get(position);

        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.car_list_row, null);
            holder = new ViewHolder();
            holder.tvCarName = (TextView) convertView.findViewById(R.id.tvCarName);
            holder.tvDailyPriceValue = (TextView) convertView.findViewById(R.id.tvWeeklyPriceValue);
            holder.tvWeeklyPriceValue = (TextView) convertView.findViewById(R.id.tvWeeklyPriceValue);
            holder.imgCar = (ImageView) convertView.findViewById(R.id.imgCar);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        holder.tvCarName.setText(car.getCarName());
        if (car.getImage() != null) {
            holder.imgCar.setImageBitmap(car.getImage());
        } else {
            // MY DEFAULT IMAGE
            holder.imgCar.setImageResource(R.drawable.ic_action_call);
        }

        return convertView;
    }

    static class ViewHolder {
        TextView tvCarName;
        TextView tvDailyPriceValue;
        TextView tvWeeklyPriceValue;
        ImageView imgCar;
    }

}

回答1:

The only reasons getView is not called are:

getCount returns 0.
you forget to call setAdapter on the ListView.
If the ListView's visibility (or its container's visibility) is GONE. Thanks to @TaynãBonaldo for the valuable input.
ListView is not attached to any viewport layout. That is, mListView = new ListView(...) is used without myLayout.addView(mListView).

In the onPostExcute, after you create a new instance of CarListAdapter I will suggest you to update the new instance to your ListView. Indeed you need to call again

 mList.setAdapter(adapter);

Edit: setAdapter should be always called on the ui thread, to avoid unexpected behaviours

Edit2:

The same applies to RecyclerView. Make sure that

getItemCount is returning a value grater than 0 (usually the dataset size)
both setLayoutManager and setAdapter have to be called on the UI Thread
The visibility of the widget has to be set to VISIBLE

回答2:

you must verify that the list has elements might have an error when adding items to your list . To verify , use the method:

adapter.getCount();

回答3:

I faced similar problem. Here is a simple work around to solve it:

In your onCreateView, you will have to wait before the view gets created. So change your lines from this:

mList = (ListView)v.findViewById(R.id.list);
mList.setAdapter(adapter);

CHANGE THE ABOVE TWO LINES INTO:

mList = (ListView)v.findViewById(R.id.list);
mList.post(new Runnable() {
    public void run() {
        mList.setAdapter(adapter);
    }
});

Hope this will help others who would run into similar problem

回答4:

You are missing the super class in the constructor. See my example below:

public AppDataAdapter(Activity a, int textViewResourceId, ArrayList<AppData> entries) {
    super(a, textViewResourceId, entries);
    this.entries = entries;
    this.activity = a;
}

回答5:

What you have been doing is

In your adapter

public CarListAdapter(Context context , ArrayList<CarDetail> items) {

    this.context = context;
    this.items = items;

}

in your Fragment

adapter = new CarListAdapter(getActivity(),ServiceCarListFragment.this.carDetailList);

I hope you will be using FragmentActivity

You need to call

adapter = new CarListAdapter(YOUR_ACTIVITY_CONTEXT, carDetailList);

where YOUR_ACTIVITY_CONTEXT will be your FragmentActivity

回答6:

I had the same problem. And after trying all tips above my getView was still not being called. So I tried to remove the ScrollView that I used outside the ListView. Then the getView worked well. Just for add one more posibility. I Hope help someone.

来源：https://stackoverflow.com/questions/16338281/custom-adapter-getview-method-is-not-called

标签

android

android-adapter