I add nextion library but i’m getting some error.
How i fix this problem ?
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Welcome to the Arduino fora.
Support for Nextion on these fora is pretty much as follows:
You can follow the methods I set out in using Nextion displays with Arduino. My methods do not use the Nextion libraries, so I can offer help on using my methods but I cannot offer anything very helpful for any Nextion library.
The original Nextion libraries are full of bugs. There is a link from my tutorial to to some improved Nextion libraries created by Ray Livingston, I suggest those might be worth trying if you prefer to use a library.
There's also a guy on here called Seithan who has also developed his own ways of dealing with Nextion displays, you can find his methods in his tutorial on how to write code with Nextion and Arduino.
Beyond that the odd person occasionally offers a bit of help but not much.
However, as Bob says, you have not posted nearly enough information for anyone to really help you.