Problem with App Inventor Built: October 19 2022 Version: nb190b

[iggyb]

I am having problems with the File component method AppendToFile recently in both the Companion (ver 2.65). I have added the screen method ErrorOccurred with a Notifier to display the message.
The filename for the method is /Download/Data2210231600.csv.
From the compiled app the results are as follows.
With Shared scope the error is
Cannot write to file /storage/emulated/0
With Legacy scope the error is
Cannot write to file /Data/user/0/appinventor.ai_iainboyle314.BTServer/files

In the companion similar messages are given.

There is no mention of the directory or file name.

Up until yesterday I was having no problems with Android 9 only with Android 13.

Any thoughts?

Iain

[ChrisWard]

Hello Iain

You can only write to the file in Download if your App created the file - I assume that it did not, given it's location. I suggest you download to the App's ASD instead. Use Anke's extension version2:

Extension to download a file to ASD (app-specific directory) without WRITE permission

Result of Avast Lab Test: Hello, Thank you for contacting Avast and reporting a false positive file detection. I'm happy to help. The reported file was checked by Avast virus specialists and based on the findings the detection was removed. The file is now marked as clean in the Avast virus database. This change may take up to 24 hours to take full effect. Please accept my apology for the inconvenience caused. If the detection persists after 24 hours, please update the Avast virus database an…

[iggyb]

Hi Chris

The app is creating the file. I have used the same blocks on Android 9 in previous apps to get data from the app to the shared Download folder so it can be exported for use on a PC. They all work OK.

I installed one of these apps on my new Android 13 device and got write permission errors.
I have tried most of the things I could find in the posts here to get it to work with little success.

The current problem is occurring with my Android 9 device which never happened before.

Iain

[Anke]

Show your (relevant) blocks.

See also e.g. here:

Using storage scope type app to share data between screens

This one doesn't work with Companion and the compiled APK on Android 11+ as it doesn't delete the text file when Companion or the APK is closed. Therefore, after testing with Companion, the file cannot be overwritten via the APK and vice versa. So either you do not test with Companion or delete the file via Companion before closing Companion or the file name must be different with Companion and APK. Note: If the user uninstalls and reinstalls the app it does not work anymore, because the…

Error 2101 with the .APK

If the File was created by Companion before you try to test with the APK, it does not work, because the file was created by another app and no longer be overwritten / accessed by a new app (on Android 11+). Two options: delete the file via Companion before closing Companion or the file name must be different with Companion and APK. See also here:

[iggyb]

Hi
apologies to all.
It was my bad programming.
The file writing was happening inside a timer loop and I was using a variable inside the loop to store the filename. Changed this to a Global variable and all OK.
I think Android 13 has got to me.
Thanks for the suggestions.
Iain

[Anke]

@iggyb

It was my bad programming.
The file writing was happening inside a timer loop and I was using a variable inside the loop to store the filename. Changed this to a Global variable and all OK.

It would be helpful if we could understand where your problem was and how you fixed it. So show your blocks before and after. This would allow other users to learn from it as well.

[iggyb]

Hi Anke
I have uploaded the 2 blocks image
The error was to have the variable Fname in the timer block.
The fix was to have a Global variable GFname outside the timer block and to replace Fname with GFname.

Iain