forum

Home / DeveloperSection / Forums / How to detect click event at empty space of gridview inside linearlayout in android?

Ask Question

How to detect click event at empty space of gridview inside linearlayout in android?

Norman Reedus383619-Nov-2014

I have a following problem. I have a GridView inside LinearLayout as image below. I want to detect click event when user click at empty space of GridView, in the image, the location that I want is the red area and also inside the green area.

But I have following problems.

  1. If I add onClickListener for GridView: error because Adapter cannot add click event.
  2. If I add onItemClickListener for GridView: I just can detect where exist items (in the image is the white box)
  3. If I add onClickListener for LinearLayout I just can detect click event on green area, not red area.

So how can I fix above problem.

@Edit: my layout looks like:

<LinearLayout>

  <GridView

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"/>

</LinearLayout>

androidjava android layout 
Updated on 19-Nov-2014
Norman Reedus

Norman Reedus

Follow

Can you answer this question?

Answer

1 Answers

Elena Glibart

Elena Glibart

19-Nov-2014

Since the parent LinearLayout can be assigned its own OnClickListener, the issue is only how to detect a click within the GridView that occurs outside of its child Views. You can subclass GridView and override the dispatchTouchEvent() method to accomplish this. Using the pointToPosition()method, we can determine if a touch event occurs outside of the child Views, and use an interface to notify a listener if it is. In the following example, the OnNoItemClickListener interface provides that functionality.

public class TouchyGridView extends GridView
{
    // Depending on how you're creating this View,
    // you might need to specify additional constructors.
    public TouchyGridView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
    }
 
    private OnNoItemClickListener listener;
    public interface OnNoItemClickListener
    {
        public void onNoItemClick();
    }
 
    public void setOnNoItemClickListener(OnNoItemClickListener listener)
    {
        this.listener = listener;
    }
 
    @Override
    public boolean dispatchTouchEvent(MotionEvent event)
    {
        // The pointToPosition() method returns -1 if the touch event
        // occurs outside of a child View.
        // Change the MotionEvent action as needed. Here we use ACTION_DOWN
        // as a simple, naive indication of a click.
        if (pointToPosition((int) event.getX(), (int) event.getY()) == -1
            && event.getAction() == MotionEvent.ACTION_DOWN)
        {
            if (listener != null)
            {
                listener.onNoItemClick();
            }
        }
        return super.dispatchTouchEvent(event);
    }
}

Liked By