Backup Files

JonPM · Feb 16, 2012

I have many files within my app that get moved to DirInternal on install. I would like to offer the option to backup these files if the user decides to uninstall the app, or (like several who have emailed me) for users who wipe their phones/devices frequently. My question is where is a place that I can backup these files too that won't get deleted if a user uninstalls the app? I plan on offering the user the option to backup to Internal memory and/or External. I am guessing I would need to use MakeDir, but I'm not sure where a safe place for the files are. Can anyone help?

margret · Feb 16, 2012

You can most times do something like this: File.ListFiles("/mnt"). This will show the directory structure of the device. On my device I see directories like:

/mnt/media
/mnt/sdcard

You can then make a directory like you App name on one of these like:

/mnt/sdcard/myappname/backup/data

Then copy all the data to that directory. If the user uninstalls your app this directory will not be deleted.

JonPM · Feb 16, 2012

margret said:
You can most times do something like this: File.ListFiles("/mnt"). This will show the directory structure of the device. On my device I see directories like:

/mnt/media
/mnt/sdcard

You can then make a directory like you App name on one of these like:

/mnt/sdcard/myappname/backup/data

Then copy all the data to that directory. If the user uninstalls your app this directory will not be deleted.

Awesome, thanks! What is the directory for internal memory? I am assuming not all devices have sdcard or an external memory drive.

margret · Feb 16, 2012

All four devices I have, the root internal directory is "/mnt".

JonPM · Feb 22, 2012

Another question, if I do this:

File.MakeDir(File.DirInternal,"backup/2012")

Will this subfolder and its content be erased if user uninstalls?

margret · Feb 22, 2012

Yes, they will be erased in that folder. DirInternal give the APPs internal directory. You would need to do something like:

Updated, previous syntax was wrong

B4X:

File.MakeDir("/mnt/media", "yourappname/backup/data") 'Nook - Internal
File.MakeDir("/mnt/sdcard", "yourappname/backup/data") 'Kindle Fire - Internal
File.MakeDir("/mnt/sdcard", "yourappname/backup/data") 'ASUS Eee Pad - Internal
File.MakeDir("/mnt/Removable/microSD", "yourappname/backup/data") 'ASUS Eee Pad - External

This will be created outside your apps folder and in the root of internal/external memory and will not be erased if your app is uninstalled.

JonPM · Feb 22, 2012

Thanks margret

JonPM · Feb 22, 2012

Hmm, actually I am running into problems. Here is my code:

B4X:

File.MakeDir("/mnt","appname/My Backup")
Log(File.ListFiles("/mnt/appname/My Backup"))
For i=0 To FileList.Size-1
File.Copy(File.DirInternal,FileList.Get(i),"/mnt/appname/My Backup",FileList.Get(i))
Next
Log(File.ListFiles("/mnt/Jonsap/IV Drips"))

For the first Log it is stating that the directory doesn't exist. Then on the File.Copy line I get an error because the directory is invalid. And yes, I confirmed there are many files in DirInternal. Any ideas?

thedesolatesoul · Feb 22, 2012

You path is definitely wrong.
What is the device under the mount point?
It should be something like "/mnt/sdcard" (and then your app and directory)

JonPM · Feb 22, 2012

thedesolatesoul said:
You path is definitely wrong.
What is the device under the mount point?
It should be something like "/mnt/sdcard" (and then your app and directory)

I see, I was wondering what mnt was exactly. What I am actually trying to do is copy the files to a directory on internal memory. Is there a universal path for this?

Sent from my DROIDX

thedesolatesoul · Feb 22, 2012

I always use file.DirRootExternal for custom paths on the sdcard (internal memory)
file.DirDefaultExternal is your apps data path on the sdcard (internal memory).
Do a Log of both to see where they are pointed to.

/mnt is a directory on linux/android where you can see all storage devices mounted.

JonPM · Feb 22, 2012

thedesolatesoul said:
I always use file.DirRootExternal for custom paths on the sdcard (internal memory)
file.DirDefaultExternal is your apps data path on the sdcard (internal memory).
Do a Log of both to see where they are pointed to.

/mnt is a directory on linux/android where you can see all storage devices mounted.

So this will work for devices that don't have any external storage?

Sent from my DROIDX

thedesolatesoul · Feb 23, 2012

http://www.b4x.com/android/wiki/index.php/Files#File_Locations

Actually, i would like confirmation on this too.
As far as i understand these locations are on the non-removable memory not a removable sdcard.

Sent from my GT-I9000 using Tapatalk

JonPM · Feb 23, 2012

Maybe Erel can confirm for us soon. Does DirDefaultExternal get deleted when the app is uninstalled?

Edit:
Well I just made an emulator with no SD card support, and DirRootExternal fails because it tries to write to /mnt/sdcard/.
Basically all I need is a fail-safe Internal directory that I can copy files to on any device. Help?

Ricky D · Feb 23, 2012

I would think that DirDefaultExternal would be removed because itn't it tied to your application directly?

Is there a way to see the contents of the dir from a pc or mac? Like I can on my windows phone?

I don't yet have a real device to check all this out. My samsung galaxy s2 is coming in the next few days.

If there's a way to independently look at a dir's contents you could install your app on your device, look that it's there. Do the backup then uninstall and look to see if it's still there.

Being a newbie to android I guess it's not as easy as that.

regards, Ricky

JonPM · Feb 23, 2012

Tested it on the emulator and it appears that the files in DirRootExternal are saved after an uninstall. Again problem lies with devices that do not have "external" storage (like this emulator I created with no SDcard support). I cannot copy files to DirRootExternal on this emulator.

Erel · Feb 23, 2012

Maybe Erel can confirm for us soon. Does DirDefaultExternal get deleted when the app is uninstalled?

Yes. It gets deleted.

JonPM · Feb 23, 2012

Erel said:
Yes. It gets deleted.

So Erel can you help? I am looking for the directory path on internal memory that I can copy files to that won't get delete. This is for devices that don't have any "external" memory.

Erel · Feb 26, 2012

There is no such internal folder. Only the storage card is not deleted.

gwapong · Jul 24, 2013

Erel is there a sample code wherein i can backup my database from the device into the directory of my choice lets say for example d:\b4a\sample

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