Unofficial Nextion/TJC User Forum

Sending String to Text Field

Good Afternoon,

I have been trying to send a 80 character text string to a text field and have been unsuccessful.

Text field is on page 1, id #5

I send the following from an Arduino:
p[1].b[5].txt=" Active Alarm #01 Emergency Shutdown Discrete Input"
I write this to the display with 0xff, 0xff, 0xff attached to the end.

Do I need to split this up into separate lines? If so, is there a way to choose a line to write to?
I’ve tried inserting CR+LF and that has not worked for me.
Any suggestions would be appreciated.

Leon…

No need to send a long string. Just use hardcoded strings in hotspot click events.

From Nextion help:
|click|2| Trigger the specified components Touch Press/Release Event
As event code is always local, object can not be page prefixed

usage: click ,
is component’s .id or .objname attribute of component to refresh
is 1 to trigger Press Event, 0 to trigger Release Events
click b0,1 // Trigger Touch Press Event of component with .objname b0
click 4,0 // Trigger Touch Release Event of component with .id 4

Couple thoughts:

  • Does the Nextion screen return any error message? F.ex. 1A FF FF FF (details in the instruction set).
  • Does the component even accept such a long string? By default the max length of strings on Nextion is 10.
  • Is p[1].b[5] really the correct component?
  • You don‘t need any CR LF at the end of your string. In fact LF is not supported by Nextion; they only use CR (\r) for new lines. Don‘t ask me why they didn’t go with the standard \n I don‘t know.
  • Are your " characters escaped properly. A common mistake would be to write Serial.print("t0.txt=\"Hello World") - which misses the (escaped) " character at the end. The best would be to share the exact code line(s) used to send the command.
  • If you‘re sending a bunch of commands at the same time you may cause a buffer overflow. This would be indicated by an error message (see first point).

Hope this helps!
Max
*

Yes - My " characters are set up properly. If I hard code these strings, I see it just fine.

I think your suggestion about the default length of strings in Nextion is my problem. I am now able to see my string correctly.

Thanks!


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