Develop Reference

How to create hidden directory in android?

I am working on an application where I have created some directory which I am accessing through my application I want to make that directory hidden for security purpose .Such that the user can access them only within the application does not access them outside the application as like through file manager.
Any help is appreciated.
Don't make it duplicate because I search out all the answer, but no one has worked for me.

Just appending a dot before the folder name will not protect it. It is only invisible to the user. It can still be accessed from apps, including file managers and therefore the user. It's just hidden by most file managers by default.
As you want to hide the files for security purposes, you should use Android's internal storage.
From the official Android developer guide:
You can save files directly on the device's internal storage. By default, files saved to the internal storage are private to your application and other applications cannot access them (nor can the user). When the user uninstalls your application, these files are removed.
Example:
String FILENAME = "hello_file";
String string = "hello world!";
FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(string.getBytes());
fos.close();
Android developer guide
You could also encrypt your files and store the encryption key in the android Keystore.
Here is a good answer regarding encryption of files in android.
Official guide regarding the Android Keystore.

Be clear "You want to create directory or folder which is not accessible for other application"(Which is your application folder) Or Create Folder any location but it is hide from your
For First Solution is -
public static File saveFileInAppDirectory(Context context,byte[] inpute, String directoryName,String fileName){
File mypath;
File directory = new File(context.getExternalFilesDir(
Environment.DIRECTORY_PICTURES), directoryName);
if (!directory.mkdirs()) {
directory.mkdir();
}
mypath = new File(directory, fileName);
try {
InputStream is = new ByteArrayInputStream(inpute);
FileOutputStream f = new FileOutputStream(mypath);
byte[] buffer = new byte[1024];
int len1 = 0;
while ((len1 = is.read(buffer)) > 0) {
f.write(buffer, 0, len1);
}
f.close();
} catch (Exception e) {
Log.e("SAVE_IMAGE", e.getMessage(), e);
e.printStackTrace();
}
return mypath;
}
It will create Directory of your app folder Path - Android/Data/Data/Your.Package.Name/FolderName/FileName
For second Solution - just change file name
File mypath = new File(directory, "."+fileName);
If you want to achive both than just replace
new File(directory, fileName); with new File(directory, "."+fileName);

just write the directory name followed by a dot(.)
example:
.myDir or .myDir1
so these directories will not be visible through file manager. And while accessing these directories call them using dot(.) only
example:
"/path/to/folder/.myDir/"
same can be done for filename

For Hiding Folder in Android
Name of your folder is MyApplicationFolder then u need to add (.)Dot in front of the folder name like .MyApplicationFolder.
So When the Folder is created then the folder is hidden mode for images,video,etc inside but it will be visible in FileManager.

Create a file in Android with certain permission

I'm developing an Android application I have to implement a function that create a folder with different files.
I wish the files in the folders were hidden, and this point is not a problem, but I want assign certain permission to files, for example I need that files are not readable / writable by user but only from application.
Also I wish the files in the folder were deleted if the application was uninstalled.
This is the code that i use to create hidden folder:
File JSONStorage = new File(Environment.getExternalStorageDirectory(), ".BMA");
if (!JSONStorage.exists()) {
if (!JSONStorage.mkdirs()) {
Log.wtf("log: ", "Failed to create directory");
}
}

From official Android documentation:
String FILENAME = "hello_file";
String string = "hello world!";
FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(string.getBytes());
fos.close();
This will create file on device internal memory. This file can be read only by application. (Context.MODE_PRIVATE)

Android - Write file to assets folder

I want to download some data and store it into a file. I am aware that I cannot write to the assets dir or any other place because of the sole nature of the APK file.
I am wondering, if I create a file with something like:
FileOutputStream fileout = openFileOutput("text.txt", MODE_PRIVATE);
OutputStreamWriter outputWriter = new OutputStreamWriter(fileout);
outputWriter.write("write this string to file.");
outputWriter.close();
Since I cannot write any files to assets or any raw dir, where it will be written?
What will the location of that file be? Where will it be located in the Android file system ?

Since I cannot write any files to assets or any raw dir, where it will be written?
openFileOutput() writes to internal storage.
What will the location of that file be? Where will it be located in the Android file system ?
That can vary by device and user. It will be to the same directory that is returned via a call to getFilesDir().

You can get the path to your file created with openFileOutput like this: MainActivity.this.getFilesDir().getAbsolutePath()+"/text.txt" and you can read it using an object of FileInputStream FileInputStream fis = new FileInputStream(new File(MainActivity.this.getFilesDir().getAbsolutePath()+"/text.txt"));

How to include external WAV files in Android

A few WAV files used by my app are currently located in res/raw. These files need to be accessible by the user after the app is installed. So ideally my app should create a folder on the device and put the files in it. Any idea/suggestions on how to do this?
soundIds[0] = soundPool.load(test2Activity, R.raw.snare, 1);
soundIds[1] = soundPool.load(test2Activity, R.raw.snare2, 1);

You can access the sd_card, so you can create a directory and put there your files
// create a File object for the parent directory
File yourDirectory = new File("/sdcard/YourDirectory/");
// have the object build the directory structure, if needed.
yourDirectory.mkdirs();
// create a File object for the output file
File outputFile = new File(yourDirectory, filename);
// now attach the OutputStream to the file object, instead of a String representation
FileOutputStream fos = new FileOutputStream(outputFile);
The output file should be your sound that you have loaded from res/raw.
My advice would be to just copy the sound to the folder, and still use the sound from res/raw from within your app because
1) it is easier since you can access it as a resources
2) you are sure the user didn't deleted the directory.
Remember to put the user permission "android.permission.WRITE_EXTERNAL_STORAGE" in the manifest

write private file to internal storage

I trying to write some files on the internal storage.
I saw theFileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE); on Data Storage and I understood that the file will be private to my application.
but the problem is it can only open a file without a path, so first I opened a new directory file with file.mkdir(), but now, how do I write the file as private ?

I saw theFileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE); on Data Storage and I understood that the file will be private to my application.
Correct. They will be private by default.
but the problem is it can only open a file without a path, so first I opened a new directory file with file.mkdir(), but now, how do I write the file as private ?
Your files that you create in subdirectories off of in getFilesDir() are private by default -- you do not have to do anything special to make them be private.

If you call Context.openFileOutput() the file will always be written into your application's data directory (i.e. "/data/data/appname/filename"). You cannot use sub folders here!
The documentation for this function says
nameThe name of the file to open; can not contain path separators.