Calling a listener in View Android

Question

I am trying to call a drag listener on convertView.

I am not accessing the longclick listener or the drag listener with the above code. I longclick on the image that is in gridview and the image shows a blue background that is slightly bigger than the image, but the image does not drag to a different location in the gridview.

Answer 1

"Variable 'myDragListener' is never used" hints that myDragListener is either not inside the same Java class (in your case - your custom adapter), or is not accessible (for example if myDragListener was declared public static in another class, you would be able to access it).

To solve it, you'll have to make myDragListener accessible, or instead, make your adapter implement View.OnDragListener itself, like in the following example:

public class ImageAdapter extends BaseAdapter implements View.OnDragListener{ //Edited

    Context context;
    LayoutInflater inflater;


    public MyAdapter(Context context) {
        this.context = context;
        inflater = LayoutInflater.from(context);
    }

And the getView() function:

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder viewHolder;
    if (convertView == null) {
        convertView = inflater.inflate(R.layout.activity_column, null);
        viewHolder = new ViewHolder((ImageView) convertView.findViewById(R.id.ColPhoto));
        convertView.setTag(viewHolder);
        convertView.setOnDragListener(this); //Edited
    } else
        viewHolder = (ViewHolder) convertView.getTag();

    viewHolder.iv.setImageBitmap((Bitmap) array.get(position).get(TAG_IMG));
    viewHolder.position = position;
    return convertView;
}

@Override
public boolean onDrag(View v, DragEvent event) {
    Log.v("draglistener", "draglistener");
    switch (event.getAction()) {
        case DragEvent.ACTION_DRAG_STARTED:
        case DragEvent.ACTION_DRAG_ENTERED:
        case DragEvent.ACTION_DRAG_EXITED:
        case DragEvent.ACTION_DRAG_LOCATION:
        case DragEvent.ACTION_DRAG_ENDED:
            return true;
        case DragEvent.ACTION_DROP:
            //imageAdapter.addNewImage(v, event);
            break;
        default:
            break;
    }
    return true;
}

Please note that instead of calling getSystemService, it's preferable to pass Context as a parameter to the adapter's constructor, and then define the inflater once, via inflater = LayoutInflater.from(context).

Also note that the call .setOnDragListener() requires API Level 11 and above.