Update button state in Blynk app through the code

Question

I'm using Blynk along with a WeMos D1 R2 and i can change modes through an ON/OFF button.

I can succesfully change mode and make my application go from mode 1 (irrigation) to mode 2 (Fertilization), but through the code i manage to switch from mode 2 to mode 1(after my code does what it is meant to do).

However, i cannot make the button show up as being in mode 1 again, if the application is working properly in mode 1. Any ideas on how to update button condition?

My code follows(below the code you can see the app and the button Using the V1 virtual pin):

void setup()
{
  Serial.begin(9600);             // opens serial port, sets data rate to 9600 bps
  Blynk.begin(auth, ssid, pass);
  pinMode(Relay1, OUTPUT);        // Setup Relay pin as output pin
  pinMode(Relay2, OUTPUT);        // Setup Relay pin as output pin
//pinMode(led_pin, OUTPUT);
  pinMode(sensor_pin, INPUT);
  digitalWrite(Relay1, LOW);
  digitalWrite(Relay2, LOW);
  digitalWrite(Relay1,HIGH);
  digitalWrite(Relay2,HIGH);

}

BLYNK_READ(V8)
{
  Blynk.virtualWrite(8,level);    // virtualpin 8 distance
}

BLYNK_WRITE(V1) 
{
  pinValue = param.asInt(); 
}

BLYNK_READ(V5)
{
  Blynk.virtualWrite(5,RH);       // virtualpin 8 distance
}

BLYNK_READ(V6)
{
  Blynk.virtualWrite(6,temp);     // virtualpin 8 distance
}



void loop()
{
  Blynk.run();
  timer.run();
  if (pinValue==0)
  { 
    // some code here
  }
  else //(digitalRead(sensor_pin) == 1)
  {
    // some other code
  }}

else {
  // a lot of code here
  pinValue=0;                     // here i set pinValue to 0 again in order to return to mode1
}
}
BLYNK_READ(V1)
{
  Blynk.virtualWrite(1,pinValue); // virtualpin 1 state
}

//End of program

Answer 1

BLYNK_READ() is documented as:

BLYNK_READ(vPIN)

BLYNK_READ defines a function that is called when device is requested to send it’s current value of Virtual Pin to the server.

That means it is called when the app or the Blynk server requests a state from the hardware/sketch, such as when the app first connects or reconnects to the Blynk server, or when the hardware reconnects to the Blynk server due to some network problem.

But if you just want to update the virtual pin V1 at an arbitrary time in your sketch, just call:

Blynk.virtualWrite(V1, pinValue);

at the point in your code where you want to "change" the button's current state. Not in the BLYNK_READ() function, but in your main code, such as:

[...]
else {
  // a lot of code here
  pinValue=0; //here i set pinValue to 0 again in order to return to mode1
  Blynk.virtualWrite(V1, pinMode);
}
[...]