Not able to display previous data in ListView in Android while using notifyDataSetChanged()?

Question

I am not able to display previous data displayed in ListView when using notifyDataSetChanged() method of adapter. Used String array (even tried ArrayList<String> ) for storing data.

I have tried almost all answers relevant to this question but couldn't get the correct result. Any help will be appreciated. In my code I am trying to modify the String array.

MainActivity

public class MainActivity extends ActionBarActivity implements View.OnClickListener{

    String countryArray[];
    Button add;
    CustomAdapter adapter;
    ListView list,newList;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        countryArray = new String[3];
        countryArray[0] = "India";
        countryArray[1] = "USA";
        countryArray[2] = "England";
        adapter = new CustomAdapter(this,android.R.layout.simple_list_item_1,countryArray);
        list = (ListView) findViewById(R.id.lvCheckList);
        newList = list;
        list.setAdapter(adapter);
        add = (Button) findViewById(R.id.bAdd);
        add.setOnClickListener(this);
    }


    @Override
    public void onClick(View v) {
        countryArray[2] = "belgium";
        adapter.notifyDataSetChanged();
    }
}

CustomAdapter

public class CustomAdapter extends ArrayAdapter<String> {

    Context context;
    String[] values;
    View rowView;

    public CustomAdapter(Context context, int val, String[] objects) {
        super(context,val,objects);
        this.context = context;
        this.values = objects;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if(convertView == null) {
            LayoutInflater inflater = (LayoutInflater)    context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            rowView = inflater.inflate(R.layout.test, parent, false);
        }
        TextView tx = (TextView) rowView.findViewById(R.id.tv1);
        ImageView iv = (ImageView) rowView.findViewById(R.id.iv1);
        tx.setText(values[position]);
        iv.setImageResource(R.drawable.Image1);
        return rowView;
    }
}

Answer 1

Please check this line in your code.

rowView = convertView;

And when you put notifydatasetchanged() method, rows will update and refresh. So put this method in getView() after fetch data.

Please check this link .

Answer 2

You can override the onResume method which belongs to Activity. You need to add this method to your activity.

    @Override
public void onResume()
{
    super.onResume();
    adapter = new CustomAdapter(this,android.R.layout.simple_list_item_1,countryArray);
    list.setAdapter(adapter);
}

Answer 3

Change your getView() method of custom adapter like this..

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

            rowView = convertView; //you are missing this line
            if(convertView == null) {
                LayoutInflater inflater = (LayoutInflater)    context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                rowView = inflater.inflate(R.layout.test, parent, false);
            }
            TextView tx = (TextView) rowView.findViewById(R.id.tv1);
            ImageView iv = (ImageView) rowView.findViewById(R.id.iv1);
            tx.setText(values[position]);
            iv.setImageResource(R.drawable.Image1);
            return rowView;
    }