How to reload Base Adapter from getView method

Question

i need to reload adapter when buton was clicked. But how can i perform it? My code is below.

public class CustomGridAdapter extends BaseAdapter {

private Context context;
//private final String[] gridValues;
ArrayList<Bitmap> arrayList;
ImageButton i1;

//Constructor to initialize values
public CustomGridAdapter(Context context, ArrayList<Bitmap> ob) {
    arrayList = ob;
    this.context = context;
    // this.gridValues     = gridValues;
}

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

@Override
public Object getItem(int position) {

    return null;
}

@Override
public long getItemId(int position) {

    return 0;
}

public View getView( int position,  View convertView,  ViewGroup parent) {
    final int pos = position;
    // LayoutInflator to call external grid_item.xml file

    LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    View gridView;

    if (convertView == null) {

        gridView = new View(context);

        // get layout from grid_item.xml ( Defined Below )

        gridView = inflater.inflate(R.layout.grid_item, null);
        ImageView imageView = (ImageView) gridView
                .findViewById(R.id.grid_item_image);

        imageView.setImageBitmap(arrayList.get(position));
        ImageButton imageButton = (ImageButton) gridView
                .findViewById(R.id.imageButton);
        imageButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Log.d("myLogs", "Yes, onclick "+pos);
                arrayList.remove(pos);
                 !!!THERE I NEED TO RELOAD IT
            }
        });
    } else {

        gridView = (View) convertView;
    }

    return gridView;
}

}

Answer 1

First of all, you have to set the event and use it in your activity... you will have to modify your adapter and add to it an OnClickListener attr:

private Context context;
private OnClickListener listener;
ArrayList<Bitmap> arrayList;
ImageButton i1;

//Constructor to initialize values
public CustomGridAdapter(Context context, ArrayList<Bitmap> ob, OnClickListener listener) {
    arrayList = ob;
    this.context = context;
    this.listener = listener;
}

And then to set your setOnClickListener, you have to do the following:

imageView.setImageBitmap(arrayList.get(position));
ImageButton imageButton = (ImageButton) gridView
            .findViewById(R.id.imageButton);
imageButton.setOnClickListener(listener);

Then, in your java, you need to let your activity implements OnClickListener, and then override the onClickListener method, where you can use the following method to reload your list:

@Override
public void onClick(View v) {   
        adapter = new CustomGridAdapter(MyActivity.this, myArrayListWithMyData, MyActivity.this);

        listView.setAdapter(adapter);

        listView.invalidate();
}

To set the adapter, you can pass your context (this, for example) as argument for the OnClickListener:

adapter = new CustomGridAdapter(this, myArrayListWithMyData, this);

Hope it helps!

Answer 2

I believe you can use NotifyDataSetChanged(); and that should reload the data.

Answer 3

The problem with your code is that your list is reusing the old views and when the view gets reused, listener is not re-registered for current view as you are registering listeners only when a new view is created (not reused). Use the below code :

...    
if (convertView == null) {
                gridView = new View(context);
                // get layout from grid_item.xml ( Defined Below )
                gridView = inflater.inflate(R.layout.grid_item, null);
            } else {
                gridView = (View) convertView;
            }
            ImageView imageView = (ImageView) gridView.findViewById(R.id.grid_item_image);
            imageView.setImageBitmap(arrayList.get(position));
            ImageButton imageButton = (ImageButton) gridView.findViewById(R.id.imageButton);
            imageButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.d("myLogs", "Yes, onclick " + pos);
                    arrayList.remove(pos);
                    notifyDataSetChanged();
                }
            });
    ...

For more details on using and optimizing ListView, refer to this Blog.