Variables are always necessary?

[ABG]

@Jairo_Rua

are there apps that don't need variables?

No global variables here ...

Autosave with no buttons

It's possible to use TinyDB tags/values for all your global variables, so everything is saved as you use it. Here's an example ... This is version 2 of an app originally documented at Where’s MIT? Use App Inventor 2 to search from the Big Bang to locate the Massachusetts Institute of Technology (MIT) within the Universe Abe Getzler Sample run Start at the Big Bang [The Big Bang.png] We start with a Web Viewer pointing to a web page on The Big Bang, and a List Picker set to show the super…

Sum of time duration

Here is a blocks-only solution, which you can dress up as you like ... [blocks] [Capture] [formatMS] [HHMMss] [Intervals] [NN] [refreshDisplay] [startTime] total_duration.aia (5.9 KB) [when btnClear LongClick] [when btnStart Click] [when btnStop Click] [when Clock1 Timer] [when Screen1 Initialize] [Designer]

The MIT HelloPurr tutorial