Joshua Lamson - Custom Drawing with Canvas

When you’re creating a new View to display some complex data, it’s easy for the number of View objects you’re using to get out of control. Between elaborate shapes, shaders/colors, and text in specific places and orientations, using only Android Views and layouts can turn your layout into a dense, complicated mess. Luckily, there’s a better way to add all your customizations. What you need is a blank Canvas! (Literally, android.graphics.Canvas). In this session, we’ll delve into the details of using a Canvas to display anything you need in a truly custom way. You’ll leave this talk knowing how to:
– Paint custom shapes, Paths, and text onto Canvas
– Override a View’s draw methods to draw on it’s Canvas
– Override a ViewGroup’s draw methods to draw over, under, and around it’s children
– Overriding a Drawable’s draw methods to create custom re-usable Drawables
– Update your View’s state in response to touches and state changes
– And how to do all of the this while keeping your Views performant and and your app buttery-smooth.