LCD text disappearing

Hi! I am using the LCD widget and I am updating only select cells by indicating row and column for first character I transmit. There are some few cells that I update every second, but most I only update every 15 or 30 minutes.

It works nicely if I stay in the same tab.

When I change tabs some of the content on the LCD are lost. The text that I updated 15/30 minutes before is lost eventhough I have not written any text to those cells.

Does anyone know if I am doing something wrong?


I had such problems with LCD. Now I prefer use labels instead as workaround, so no more loss of data.

Hmm… I had hoped I had done something wrong…

I wonder if this issue will be solved soon - It would be quite a work for me to change my code.

I do not think the workaround of using labels will work well for me, eventhough it is a good suggestion. I am using the LCD to show the immediate status and this may include showing a timer, temperatures and free text messages.

To do that I concatenate datas like this for example->

byte bars;
byte WiFi_Quality;
String WiFi_Quality_display=(WiFi.SSID_str+Mode_WiFi_display_str+" Level “+String(bars)+”/5"+" Quality “+String(WiFi_Quality)+”%";

Blynk.virtualWrite(V5, WiFi_Quality_display); //display label Info

Do you have a device selector?

No I do not. I only use one device, an Arduino Due.

I have also seen cases where I switch to a tab with an LCD widget, and it is missing anything that is not constantly updated. I never quite figured out when or why, so I just added in a button routine that refreshes any static display info :neutral_face:

I do believe the Developers tried to fix something similar a while ago, but whether it was not finalised or is just a returning issue… I don’t know.

How do you ‘refresh any static display info’?

Same way I put it there in the first place… I just have it all in one function and just add a new call to that function.

Hmmm… I am afraid that will not work for my purposes.

Doesn’t really work for me either… but until the issue is confirmed/fixed, well it is better than nada.

True - except it will be quite a job for me - I am only programming as a hobby and now I have to make some quite fundamental changes in a 2000 line program; not a small task with my time and skills…

I wonder if this issue has been resolved or not.
I also have a similar issue. My lcd does refresh but the first line doesnt.
This happens when I view the app after, hours, days etc
If you leave your screen on and view the app its fine. But when you leave the app and come back to it at a later stage the first line of lcd is empty until a new state occurs.
Used 4 different android devices and running the code on a Particle Photon.
With and without device selector.

If you sends LCD updates mostly for the second line - it is expected to have such behavior, as the server will cache some limited number of the latest lcd.print calls.

Sorry, I cant understand what you mean.
Can you please explain a bit better so I can correct it?
I have 5 states in my code.
Whenever a state changes, both lines on the lcd are updated.
If its in the same state and you close the mobile screen then reopen to see Blynk app, first line is empty. If I press a button to set the same state, lcd refreshes and is fine. Leave the app and reopen, line missing again.

We have a specific logic for handling values for such widgets like LCD and Terminal, as they can have multiple value updates calls. So it could be possible if like you updated first line, and then several times updated only second line, so it can result in only the send line after next profile reloading. But now with your latest comment it looks more like a bug. Can you try our beta app’s version, so you can send logs from it and we’ll investigate them for this issue? To get beta version - open blynk page on google play, scroll the screen till the ‘join beta test’ field.

Ok thanks for that. Will do and get back with the logs.

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