In this tutorial we will create a drawing application named paint with App Inventor that draws strokes with three different colors.
We propose to create the design of the application, with the following visual:
To program the application, App Inventor proposes to use The Space Blocks which allows to create a program in the form of a block diagram. Very simple to use but requiring a bit of programming logic.
Here is the paint program realized in the Blocks space of the Inventor App: