Android Question Writing Files to internal memory

[brianh]

Another "dummies" question from a B4A newbie which probably has a simple answer.

In a B4A app I am trying to write a file to internal memory but I keep getting errors. I want to use internal memory as I might be switching SD cards so want the data there all the time. 2 Samples of my code are:-

Code example 1:-
Dim list1 As List
Dim directory1, testfile As String
directory1 = File.DirRootExternal
testfile1 = "testfile1.txt"
File.WriteList(directory1, testfile1, list1)

Code example 2:-
Dim list1 As List
Dim directory1, testfile As String
directory1 = "/"
testfile1 = "testfile1.txt"
File.WriteList(directory1, testfile1, list1)


The first example writes perfectly OK to external memory (as I can detect it using File.Exists) but the 2nd one for the internal memory location generates errors. I have tried different paths but they all cause errors unless I use File.DirInternal then it's OK (but I understand that I cannot then access the saved file outside the app).


The code above is based on the "Android Tutorial - Text Files" dated Nov 28 2010 so I'm not sure if those code examples are still valid.

Many thanks

Brian

 

[Mahares]

I have tried different paths but they all cause errors unless I use File.DirInternal then it's OK (but I understand that I cannot then access the saved file outside the app).

Your statement is correct. Use File.DirInternal. , But if you want to access the file outside its app, you need to use File.DirRootExternal

 

[brianh]

Mahares

By playing around (and looking at many other answers), I've found I can get it working by using "/storage/emulated/0/Data/{..etc.....}/" instead of just "/" for the internal directory path (at least on my particular phone).

Brian

 

[Erel]

You should never use hard coded paths.

The available folders are described here: https://www.b4x.com/android/forum/threads/text-files.6690/#content

If you want to use runtime permissions: https://www.b4x.com/android/forum/threads/67689/#content

 

[brianh]

Erel

I want to be able to copy, when needed, a file that contains specific (but different data) from my PC onto my phone and then pick it up in the application. From the link you provided, File.DirInternal / File.DirInternalCache would seem to be the only pre-defined paths for the internal memory but the link also says that these directories are only usable by my own application (so cannot be seen by Windows Explorer when I copy the wanted file to my phone). I'm actually using File.DirInternal for some app configuration data but I need to access other file(s) at run-time.

I cannot use the IDE Files facility as the file will only be created/named/copied some time after I've compiled my app so need some other way of locating the file.

What I think I need is something like File.DirRootExternal but for the internal memory (File.DirRootInternal ??) to which I can then add specific sub-directory paths to where I've copied my file. I don't want to use external memory (ie SD card) as I often switch memory cards.

I accept that using the fuller path I detailed in my reply to Mahares is bad practice but I'm not sure what else I should use.

Although I'm still very much a beginner at B4A, many thanks for an excellent program.

Brian

 

[Erel]

File.DirRootExternal doesn't point to the sd card. It points to the secondary storage. In older devices (Android 2.0) it was the sd card but on newer devices it is internal.

You can check the path with Log(File.DirRootExternal).

 

[brianh]

Erel
Thanks for the clarification - I did not realise that "storage card" meant on-board memory. I've changed my code to use File.DirRootExternal and it now works OK.
Brian