How to use app inventor and arduino

[ecvary]

Hi, all,.
I'm learning about App Inventor. I've googled references and tutorials, but I can't understand it. maybe in this forum I can learn better... in my code the numbers can be read on the label in the application, but the background color in the "call mode_setup" block does not change.
how to communicate between arduino and app inventor.
Thank you

void loop() {

  mode++;
  Serial.println(mode);
  bluetooth.print(mode);
  bluetooth.print("/");  //ascii 47
  delay(2000);
  if (mode > 3) {
    mode = 0;
  }
}

SourceconnectionAppInv.zip (3.7 KB)

[kmin]

So you confirm that you receive numbers 1-4 from arduino to your app?

[ecvary]

Yes, app receive number from 1-4.

[kmin]

I don't use AppInv, but I expect:
You have now 3 conditions, even if one of them is setting background to green, 2 of them are always setting background to gray. So result is always gray.

Try to set only one condition in mode_setup, and check if it works for that number.

Common logic would be
if
then
elseif
then
elseif
then
else

...