Memory space

I wonder if it’d be possible to give the user the ability to transfer the app to “external” memory (ie the SD card) as it’s quite hefty on internal space?


Someone asked this via email a few weeks ago and I’ve posted my reply below. As an added note, in the early days of Flowx, the SD card caused much headaches. Since removing it (around 2017), I haven’t had those headaches and very few users have requested it. I think larger internal storage in newer phones is overcoming this issue.

To be honest, I haven’t looked into it recently. The way it used to work is that the app would request the path from the OS and it’ll save data there … I decided to read up on it and it’s still confusing. Flowx does use external storage but not the removable(SD card) external storage:

What's the current status of Internal vs External vs Removable vs Adoptable Storage on Android? - Stack Overflow

What is the Difference Between External Storage and Internal Storage? :Cashify Explains | Cashify Blog

Anyway, Flowx is saving to the external storage, but not the SD card. According to this, there is a legacy flag to allow users to save to the SD card:

java - How to get permission to write files into SDCard in Android 6.0+ - Stack Overflow

The encouraged option is to use the Storage Access Framework but, man, does this look complicated:

Open files using storage access framework  |  Android Developers

Saving to the SD card causes problems because if it disappears it can cause issues, e.g., if the map tiles are cached there, Flowx would have to download them again. Or if certain settings or the storage database is saved there, we lose all the settings and data. So I’d have to split the data I store between critical (store on internal storage) and non-critical (store on SD card). This is extra complexity in the code, more surface area for bugs and maintenance.

Even with a disclaimer, bugs will still happen and users will still email me for support or they will rate the app 1-star. This is the main issue. It’s like my help pages, users will still email for stuff that is in the help. I once had a user email me with a question, I answered the question and included the link to the help page, and he replied with another question that was in the help page I sent.

I’m a solo developer so I’m limited with time so I need to be careful with support issues. There are 80,000+ monthly users, if I got 1% of users emailing for support, that’s 800 emails a month.

A separate build is difficult too. I don’t have automated scripts set up. I do it all manually.

I have been thinking about storage and one option I’m considering is to store data as zipped content. This will slow the load speeds but will continue to use one storage system. I’ve also considered adding an option to be more brutal in clearing old data. Currently, I keep the past two forecast releases, but this can be reduced to one forecast (halving the data). For me, Flowx uses around 300MB so I think the sip option and brutal purging of data will reduce storage to 30-40%. BTW, these two features are far easier to implement compared to managing data in two places and having logic to cope with missing data.


Thank you for your response. I hadn’t realised that it can cause problems.

Yes, I may need to bite the bullet and get a 64gig phone. :+1:


Sounds like the easiest solution - for me :slight_smile:


@Lexicalluthor some apps won’t work properly if moved to SD Card for example my pharmacy app when I look it can be moved to SD but after moving it it stops working some apps won’t let widgets work when app is on SD. I didn’t know about all the stuff @duane posted about it crazy how fast things get complicated :joy: By the way Good Seeing You on the Forum it’s Been Awhile Hope all is Well and You and Your Family Have a Wonderful Holiday Season


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Hi Brian! Thank you for your kind response to my enquiry. Yeah, as I said to @duane I hadn’t realised that moving an app to the SD card can cause problems. The very fact that widgets may not function on its own rules it out right away. I’m smiling to myself now because about 3 years ago I sent a message to Duane complaing that latter versions of Flowx were no longer able to be used on my phone. He very kindly sent me (by email attachment) an old version of Flowx which I was grateful for but finally decided to upgrade the phone to my current one. So it looks like the frugal Luddite in me may have to give in to the upgrading society bandwagon! :grin:

Thank you for your kind wishes which I return to you in full measure. May 2022 bring health, peace and prosperity to you and your family.