Dear Perry,
I'm trying to use your method, I've read almost all your posts, but I think I missed something.
I need the arduino to receive a value entered on the Nextion screen by the user.
Are there any examples of how to do this with your method?
I apologize if this has been presented before but have not figured out how to do it yet.
Thank you for your attention and congratulations for the beautiful work, after much research and difficulties I believe your method is the best solution I have found so far. But I'm stuck in this detail.
Hello Tartrux,
Welcome to the forum.
This probably ought to be a separate question, not one tagged on to the end of someone else's question; thank you Ballscrewbob for moving it.
I need the Arduino to receive a value entered on the Nextion screen by the user.
Do you mean that you have created a numeric keypad on the Nextion and want to send the number entered to the Arduino? How have you created the keypad (if you have created a keypad)? and what are you doing with the key presses? Please explain a bit more what you are doing and how you are doing it.
My general philosophy in my methods is to send any touch events to the Arduino, have the Arduino process them then send the result back as text to be displayed. The examples in my tutorial all work this way, although there isn't an example exactly like what you are asking for. Have you looked at the examples in part 4 of my tutorial, in the file Arduino Nextion additional features 43V1.zip ?
[Note to anyone reading this some time in the future, those will change at some point but the above link will not, so might be broken if you are reading this a long time after I posted it. Try part 4 of my tutorial 'using Nextion displays with Arduino'.]
Thank you for your attention and congratulations for the beautiful work, after much research and difficulties I believe your method is the best solution I have found so far.
Thank you! 
Yes, the idea was this, I created a keypad where the user enters a value and sends it to the arduino.
On the keypad, at each key pressed, I add to a textbox, when the "enter" key is pressed, I save the content in a Nextion variable.
In Arduino I get this variable through the callback function. The problem is that sometimes it works and sometimes it doesn't.
For this reason I intend to adopt the method you developed, I believe it will solve my problem.
In Arduino I get this variable through the callback function.
I take it from that that you are using the Nextion library at the moment. If you use my methods you will have to re-write everything to my way of working, they are not compatible with the Nextion libraries.
For this reason I intend to adopt the method you developed, I believe it will solve my problem.
What you want to do is simple with my methods; each button on the keypad has a different identity (index of type) from 0 to 9, send that to the Arduino, let it add everything up and send the result to a text box so the user can see it.