Android Programming: The Big Nerd Ranch Guide, 4th Edition

Simple Property Animation

Now that you have the scene set up, it is time to make it do your bidding by moving parts of it around. You are going to animate the sun down below the horizon.

But before you start animating, you will want a few bits of information handy in your activity. Inside of onCreate(…), pull out a couple of views into properties on MainActivity.

Listing 31.4  Pulling out view references (MainActivity.kt)

class MainActivity : AppCompatActivity() {

    private lateinit var sceneView: View
    private lateinit var sunView: View
    private lateinit var skyView: View

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        sceneView = findViewById(R.id.scene) ...