How to write to Android persistentdata file. Unauthorized Access

Unity Engine
1

I’ve been scouring google for hours trying to figure out why I can’t write to androids persistentdata path, I’m trying to save a txt file.

I’ve tried to create the directory first and still I get the error, I’ve changed to External access for write permissions and I’ve even tried adding android:requestLegacyExternalStorage=“true” to the manifest, which was suggested all over google.

Could someone please ellaborate on how to Read and Write from Android?

2

Should just work. You don’t need to create the directory and in fact you can’t. It will already exist.

Some things to try:

First step is always run the game with adb logcat and see if there are any exceptions being thrown.

Then perhaps print out (to console or to a UI object onscreen) the actual path and see if it seems reasonable. Make sure you’re using forward slashes always.

2 Likes
3

Hey man, thanks for the reply

Thanks for the advice with logcat, I do already use it, would be so lost without it.

Yeah, actually, I legitimately just now got it to work with File.WriteAllText(Application.persistentDataPath + “/Save.txt”, saveData);

Originally what I was trying to do was create another folder so the path would be Application.persistentDataPath + “/SaveData/Save.txt”"

I’ve been staring at it for hours, maybe I’m looking at it wrong but for now I am able to save just in the persistent data folder.

4

Weird. That should work too. I don’t see anywhere saying that File.WriteAllText() will make the subdirectory though, so that’s probably Directory.CreateDirectory()…

5

I also want to add:
Use Path.Combine() for combining paths, not string concatenation (the plus sign you use)
Example: Path.Combine(Application.persistentDataPath, “/data.bin”)

6

Yeah, well I tried Directory.CreateDirectory() but i Just couldn’t seem to get it to work, I’ll have another crack at it and see what happens.

I have read that it’s preferable to use Path.Combine but why is that? Isn’t “Path.Combine(Application.persistentDataPath, “/data.bin”)”

the same as

Application.persistentDatapath + “/data.bin”?

7

I would guess because it reliably handles all combinations of path delimiters on either side?

Plus it is also a params argument if I recall, so you could combine any number of path chunks all at once.