What is the recommended ActionBar icon size in Material Design (Android API 21+)?

Question

First of all, this question is related: How big should Action Bar(Toolbar) icons be in the new Android Material design?

In the related question it is clear that the

Answer 1

1. There are recommendation for most features. Toolbar icons should always be 24dp, while as you say circular features (including images and floating buttons) should be 40dp. You might find different values for different views, in the page you linked or in the "Components" side menu.

   I downloaded material icons some time ago, from here or here. In both cases icons are provided in different sizes, 18dp, 24dp, 36dp and 48dp. It's up to you to choose the best size and to set an appropriate padding on the view, to ensure a 48dp clickable area. In most cases if you chose an AppCompat or Material theme it will handle sizing and padding for you.

   Apart from that, e.g. when sizing a button, I would choose Buttons from the "Components" menu, and get size info there.

2. Yes.

3. You are probably right, 48dp icons for xxhdpi should be 144x144 pixels.