Overlay a color over a view

Question

For a custom AdapterView implementation I'd like to add a color overlay to selected items. How do I add a color overlay to a child of my AdapterView?

http://stackoverflow.com/questions/14023886/android-button-selector/14024007#14024007 — Chintan Rathod, Nov 13 '13 at 12:39
I don't want to change the background of the child elements. I would like to add a color overlay. Also this should be a generic solotion as I don't know what type of view the child represents. — multiholle, Nov 13 '13 at 12:41
Then put a `CustomView` or `ImageView` over your item of list view. When selected, just change color of `CustomView` or `ImageView`. — Chintan Rathod, Nov 13 '13 at 12:44

score 10 · Answer 1 · edited Jun 02 '16 at 12:19

If you are using your own layout simply change the container to RelativeLayout (or a Layout class that inherits from RelativeLayout), and put the color overlay after the main layout. All you need is to add a View and set it's background and alpha. alpha set to the value 1 will activate this overlay, whereas setting alpha to 0 will go back to normal.

Example:

<RelativeLayout
  android:layout_width="match_parent"
  android:layout_height="match_parent">

  <!-- add your views here -->

  <View
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#8000FF00" />

</RelativeLayout>

This will overlay a green layer with 50% alpha over the other views which are before it in the layout.

score 5 · Accepted Answer · answered Nov 14 '13 at 06:49

OK, I did some more research. That's what I finally came up with:

// prepare a gray filter setting saturation to 0, or ...
ColorMatrix cm = new ColorMatrix();
cm.setSaturation(0);
Paint paint = new Paint();
ColorFilter filter = new ColorMatrixColorFilter(cm);

// ... prepare a color filter
ColorFilter filter = new PorterDuffColorFilter(Color.rgb(34, 136, 201), PorterDuff.Mode.OVERLAY);

// create paint
paint.setColorFilter(filter);


// override dispatchDraw of the view
@Override
protected void dispatchDraw(Canvas canvas) {
    if (isPressed()) {
        canvas.saveLayer(null, paint, Canvas.ALL_SAVE_FLAG);
        super.dispatchDraw(canvas);
        canvas.restore();
    } else {
        super.dispatchDraw(canvas);
    }
}

Overlay a color over a view

2 Answers2