In this chapter, we've seen how to interact with our custom views. A part of the power of building custom views is the ability to interact with them and make them interactive. We have also seen how to simply react to touch and release events, how to drag elements and calculate the delta distance between drag events, and finally how to use GestureDetector.
As rendering has been kept quite simple until now, we'll focus on making our rendering more complex and using more drawing primitives in the next chapter.