Android drawSelectorOnTop with GridView

Question

I am developing a tabbed application in which one of the fragments, CollectionsFragment, contains a GridView with an ImageView in each slot. I would like the to use a selec

Answer 1

I think you are mistaken about setDrawSelectorOnTop(boolean). The selector drawable that is being referenced here is GridView's internal selector drawable.

Even in the simplest implementation of GridView, when a grid item is clicked, the blue border is drawn around it. This is because, by default, gridview's own selector is drawn behind the item. If you call setDrawSelectorOnTop(true), the selector (blue) will be drawn over the item.

But setDrawSelectorOnTop(boolean) has nothing to do with the selector you are setting in the adapter. Whether you pass true, or false, the ImageView's selector's behavior won't change.

Solution:

Instead of setting the selector on each ImageView inside the adapter, make the GridView use your selector drawable:

GridView gridView = (GridView)view.findViewById(R.id.gridview);
gridView.setDrawSelectorOnTop(true);

// Make GridView use your custom selector drawable
gridView.setSelector(getResources().getDrawable(R.drawable.selector));

Now, there's no need for:

picture.setBackgroundResource(R.drawable.selector);

Edit:

Although I don't recommend this (obvious overhead), it should work:

@Override
public View getView(int i, View view, ViewGroup viewGroup) {
    View v = view;
    ImageView picture;

    ....
    ....

    LayerDrawable ld = new LayerDrawable(new Drawable[] 

                           // Drawable from item
                           { getResources().getDrawable(item.drawableId), 

                           // Selector
                           getResources().getDrawable(R.drawable.selector)});

    // Set the LayerDrawable
    picture.setImageDrawable(ld);

    // Don't need this
    // picture.setBackgroundResource(R.drawable.selector);

    return v;
}

Answer 2

1. Try setting the xml attribute android:drawSelectorOnTop in your activity_collections.xml file

2. See if placing gridView.setDrawSelectorOnTop(true); after gridView.setAdapter(); helps. Sometimes, the order matters (weird)

3. If all else fails, you may have to switch GridView to some other view where setDrawSelectorOnTop() is proven to work consistently.

HTH