Transitioning from one screen to another MIT App Inventor and Companion App

Hi all,

I am building a well-being application and I am having some problems transitioning from one screen to another.

This is my code:

Sign in code:


This should take the to the Home Screen, however a blank screen pops up. This is happening for all of my screens and I don't know why. Can someone please help? Thank you.

Home Screen code:

When the user clicks on mood they should be able to access the mood screen:

Mood screen code:

When the user saves their mood they should be brought to the sleep screen:

Sleep screen code:

When the user saves their sleep they should be brought to the nutrition screen:


If you decided to use different screens, then you should switch them correctly, else you will run out of memory after a while...      
The recommended method of switching screens in App Inventor
(Thanks Taifun)
 
Also see demo: multiscreen.aia