Android File Storage Guide — Internal, External & SAF Explained

What You'll Learn

How to use Android's file storage options: internal storage, scoped external storage, and Storage Access Framework.

Storage Types

Type	API	Permission
Internal	context.filesDir	None
External (app)	getExternalFilesDir()	None
User files	SAF OpenDocument	None
Gallery	MediaStore	None (Android 10+)

Internal Storage

// Write
context.openFileOutput("data.txt", Context.MODE_PRIVATE).use {
    it.write(content.toByteArray())
}
// Read
context.openFileInput("data.txt").bufferedReader().use { it.readText() }

SAF — File Picker

val openLauncher = rememberLauncherForActivityResult(
    ActivityResultContracts.OpenDocument()
) { uri -> uri?.let { readTextFromUri(context, it) } }

Button(onClick = { openLauncher.launch(arrayOf("text/*")) }) {
    Text("Open File")
}

MediaStore — Save to Gallery

val values = ContentValues().apply {
    put(MediaStore.Images.Media.DISPLAY_NAME, "photo.png")
    put(MediaStore.Images.Media.MIME_TYPE, "image/png")
    put(MediaStore.Images.Media.RELATIVE_PATH, Environment.DIRECTORY_PICTURES)
}
val uri = resolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values)

Summary

• Internal storage for app-private data
• External app-specific dirs need no permissions
• SAF for user-driven file operations
• MediaStore for shared media

---

8 production-ready Android app templates on Gumroad.
Browse templates → Gumroad