File Management

Storage Locations

External Root application file directory

/storage/emulated/0/Android/data/your.package.name/files/

• Big File (No Limited Space & Required permission)

context.getExternalFilesDir(null) // use this to access External dir

Internal Root application file directory

/data/user/0/your.package.name/files/

• Small File (Limited Space & No permission require)

context.filesDir // use this to access Internal dir

Use the Device Explorer in Android Studio to review/edit all files inside the Android emulator

Folder Operations

Get root dir path

null means get the root dir path

context.getExternalFilesDir(null)

Get public view asset folders (e.g., Download Folder)

Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)

File/Folder Operations

Check if file exists

var myFile = File(context.getExternalFilesDir(null), "ocean.mp3")
myFile.exists()

Create a folder under root dir

val customDir = File(context.getExternalFilesDir(null), "customFolder")

if (!customDir.exists()) {
    customDir.mkdir()
}

Get all files (via list)

fun getFiles(context: Context): List<File> {
    val dir = context.getExternalFilesDir(null)
    return dir?.listFiles()?.toList() ?: emptyList()
}

Write a file with FileWriter

withContext(Dispatchers.IO) {
    val file = File(context.getExternalFilesDir(null), "hello.json")
    FileWriter(file).use { writer ->
        writer.write(Gson().toJson(api))
    }
}

Write with File OutputStream

File(context.getExternalFilesDir(null), "customFolder")
    .outputStream().use { output ->
    <Your-InputStream>.copyTo(output)
}

Rename/Move file

val oldFile = File(context.getExternalFilesDir(null), "ocean.mp3")
val newFile = File(context.getExternalFilesDir(null), "new_ocean.mp3")

oldFile.renameTo(newFile)

Delete a file

File(context.getExternalFilesDir(null), "customFolder").delete()

Get URI

File(context.getExternalFilesDir(null), "ocean.mp3").toUri()