Null Object reference

[nknr]

java.lang.NullPointerException: Attempt to invoke virtual method 'int androidx.constraintlayout.motion.widget.MotionScene.getStartId()' on a null object reference in the step1 and step2

[ggfan]

I guess you are executing code before step 4 in the first task; in that sense, the code is not completed hence not ready to run, but it could run at step 4.

Closing down this one, please re-open if this is not the case. Thank you again for using the codelab and reporting the issue!