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

Norman Reedus 4069 19-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>

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

Norman Reedus

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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);
    }
}

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