Develop Reference

Cleaning up a folder on a phone

first question on this site, if improper just tell me.
I am creating an app on an adroid platform. With this app I create some files and folders in the shared document folder.
What happens is this: with every build, at least with the -cleaninstall parameter set, it is impossible to overwrite existing files and/or folders. Even after deleting them on the phone.
Probably this is due to the fact that the filesystem thinks that the new build is not the original owner of the file/folder and is therefore not authorized to delete or overwrite.
As a bypass solution I am using an "appname" variable to create a folder to store data in, if necessary I update the "appname" variable so a fresh set of folders is created, based on the "appname" but this a pretty crooked way to work.
DocumentFolder := System.IOUtils.TPath.GetSharedDocumentsPath;
AppName := 'ExpensesV2';
AppFolder := DocumentFolder+PathDelim+AppName;
if NOT DirectoryExists(AppFolder) then ForceDirectories(AppFolder);
Is there a proper way to really remove/clean up that specific folder OR get the proper autorisation.
Thank you for your valued responses!!

You don't specify how you're going about creating the folders and writing the files. There are different mechanisms for doing so depending upon the type of file you want to write (media files, documents, generic files) and who you want to have access to it (public vs app private storage). There are also additional complications with permissions and things depending upon what OS version you're targetting.
Given the information available, the best I can suggest is having a look at these links:
https://developer.android.com/training/data-storage
https://developer.android.com/training/data-storage/use-cases
The latter gives some sample cases of types of file and purpose and suggests the mechanism to use to write/read it.
In the most general of senses, if you want to write to public external storage then use getExternalStoragePublicDirectory(); but the warning note here is that the user can do as they wish with the files in the storage area; putting their own files there, renaming files, deleting files etc etc It is beyond the control of your app to manage.
If you want your app to manage the storage space properly then you need to use something like Context#getExternalFilesDir(), but then if you want those files to be externally visible you will have to share them with the system and look into things like file sharing or content providers.

Storage so my media/non media files are accessible by other apps

I am confused with the new app storage system in Android. I am not sure where my use case falls under and I need your help in telling me the right approach for this
My app captures images and generates pdf documents. Prior to Android 10, I used to store them in an app directory where the user can easily navigate to them through other files browsing app (like Files app on Samsung). In addition, these files can be accessed from within my app (so essentially read and write).
With the new storage, I am not sure how to accomplish the same thing. If I use the internal storage then user can't see them. If I use the media approach, well it seems it is only for Audio/video plus they will not be organized in a folder like I have them organized.
Am I missing something? How would I solve this problem?
Thank you

On an Android 11 device you can store your files in a subdirectory of the public Documents directory.
You can do that using classic File means or the media store or SAF.
Other apps can see them using SAF or the media store. Or with classic file means when requested all files access.
The user can see them using the default Files app on the device.

How to securely store application files within its package folder structure?

My question is pretty general; whenever an android app accesses internal storage environment path; its folder structure is created into device's "Android->Data->app_pakage".
Image files within this folder won't be viewed from gallery; which is fine.
There are lots of app which secures this files (Can't be opened directly from file manager);
Examples for this are music apps; they provide encoding of its downloaded files, so it can be accessed only from that app only. This encoding changes its extension
So my question is here, How this can be achieved?. I am looking for simplest solution, which don't require a high, complex encryption algorithms.
In-Short, I want to prevent users to access app files from file manager- internal storage

Please have a look at this link
https://developer.android.com/training/data-storage/files.html
Here there is detailed explanation.
To have files that can only be accessed from your app please use -
getFilesDir()
Returns a File representing an internal directory for your app.
Files saved here are accessible by only your app.

Download Audio file like Gaana Android app

I have created an Android Application, in that I am playing and downloading audio file from server. So when user download audio file from server he/she can't show that file in File Manager or any other media player like Gaana app.
How to make it possible?
Thanks,
Sagar.

You can save the files in Internal Storage Area. These files would be private to your app only.
Using getFilesDir() on any context provides absolute path to the filesystem directory where your internal files are saved. There in you can create directory. For more information refer here

You can use few approaches:
Download files into the private application's directory. No other apps will have access to those files. Pros of this approach is that is is the easiest way. Cons is that the inner storage might be limited in the device.
Download files saving them with incorrect file extensions. Pros: easy to implement, can save anywhere. Cons: files can be accessed, copied and renamed by any other app.
The same way as 2nd approach, but add some encryption to the files, so nobody except you can use them. This approach might require on-the-fly decryption.

Start Android app with files on sdcard or somewhere in the filesystem

I making an application with phonegap/cordova where I need to keep a lot of files up to date. Some files (mainly images) will need to be erased in time, and some new ones will get downloaded. The thing is, in Android, to manipulate those files, it seems I need to have them on the sdcard; so I copy the files the app starts with from my assets folder to the sdcard. It just seems like a waste of memory space.
Do you know if is there anyway I can start with the app having those files the app starts with already inside the sdcard? or at least somewhere I can delete them later?
Thank you.

Files that are delivered to the device as part of your APK will be stored in a form that cannot be modified by your application (other than by updating to a new version of the apk).
If you copy the files out of the APK into the private internal storage area or the external storage area, those copies can be modified, but the originals inside the apk will remain.
The most efficient solution may be to not put these files in your apk, but have your app instead download them separately on the first run, using whatever mechanism you wanted to use to change them in the future.
(Some people object to this feeling that such files are less secure against unauthorized use, but as the contents of an .apk are trivial to extract this is not a strong argument. Needing to maintain a server to download from is a slightly more substantial objection.)

You do not need to store the files on the SD Card. Each app has its own internal storage that is not accessible by any other apps. For more information see the official docs: http://developer.android.com/guide/topics/data/data-storage.html