Refer to Setup Android Google Drive Api for initial setup.
The following code backup a String to a file named backup-latest.db in Google Drive App Folder.
The App Folder is a special folder that is only accessible by your application. Its content is hidden from the user and from other apps. Despite being hidden from the user, the App Folder is stored on the user's Drive and therefore uses the user's Drive storage quota. The App Folder can be used to store configuration files, temporary files, or any other types of files that belong to the user but should not be tampered with.
- call
initBackupto sign in to Google Drive and perform backup toApp Folder. - call
initRestoreto sign in to Google Drive and perform restore fromApp Folder. backupToGoogleDrivecreate a file inApp FolderrestoreFromGoogleDriveperform a search/query for backup file inApp Folderfollowed by read operation.
class BackupActivity : AppCompatActivity() { companion object { private const val GOOGLE_SIGNIN_BACKUP_REQUEST_CODE = 1 private const val GOOGLE_SIGNIN_RESTORE_REQUEST_CODE = 2 } private lateinit var googleSignInClient: GoogleSignInClient private var driveClient: DriveClient? = null private var driveResourceClient: DriveResourceClient? = null override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) { super.onActivityResult(requestCode, resultCode, data) if (requestCode == GOOGLE_SIGNIN_BACKUP_REQUEST_CODE || requestCode == GOOGLE_SIGNIN_RESTORE_REQUEST_CODE) { if (resultCode == Activity.RESULT_OK) { val googleSignInAccount = GoogleSignIn.getLastSignedInAccount(this) driveClient = googleSignInAccount?.let { Drive.getDriveClient(this, it) } driveResourceClient = googleSignInAccount?.let { Drive.getDriveResourceClient(this, it) } if (requestCode == GOOGLE_SIGNIN_BACKUP_REQUEST_CODE) { backupToGoogleDrive() } else if (requestCode == GOOGLE_SIGNIN_RESTORE_REQUEST_CODE) { restoreFromGoogleDrive() } } else { } } } private fun initBackup() { googleSignInClient = buildGoogleSignInClient() startActivityForResult(googleSignInClient.signInIntent, GOOGLE_SIGNIN_BACKUP_REQUEST_CODE) } private fun initRestore() { googleSignInClient = buildGoogleSignInClient() startActivityForResult(googleSignInClient.signInIntent, GOOGLE_SIGNIN_RESTORE_REQUEST_CODE) } private fun signOut() { googleSignInClient.signOut() } private fun buildGoogleSignInClient(): GoogleSignInClient { val signInOptions = GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN) // .requestScopes(Drive.SCOPE_FILE) .requestScopes(Drive.SCOPE_APPFOLDER) .build() return GoogleSignIn.getClient(this, signInOptions) } private fun backupToGoogleDrive(backupData: String) { driveResourceClient?.let { driveResourceClient -> val appFolderTask = driveResourceClient.appFolder val createContentsTask = driveResourceClient.createContents() val task = Tasks.whenAll(appFolderTask, createContentsTask) .continueWithTask({ task -> val parent = appFolderTask.result val contents = createContentsTask.result val outputStream = contents.outputStream val input = backupData val inputStream = ByteArrayInputStream(input.toByteArray(Charsets.UTF_8)) inputStream.use { input -> outputStream.use { output -> input.copyTo(output) } } val changeSet = MetadataChangeSet.Builder() .setTitle("backup-latest.db") .setMimeType("application/octet-stream") .setStarred(true) .build() driveResourceClient.createFile(parent, changeSet, contents) }) task.addOnSuccessListener { driveFile -> // show success message } .addOnFailureListener { e -> Log.e(TAG, "GoogleDrive create file failed", e) // show failure message } } } private fun restoreFromGoogleDrive() { driveResourceClient?.let { driveResourceClient -> val appFolderTask = driveResourceClient.appFolder appFolderTask.continueWithTask { task -> val parent = task.result val query = Query.Builder() .addFilter(Filters.eq(SearchableField.TITLE, "backup-latest.db")) .build() driveResourceClient.queryChildren(parent, query) }.addOnSuccessListener { meta -> if (meta.count > 0) { val fileMeta = meta.get(0) } else { // viewModel.toastMessage.value = R.string.message_no_backup_found } }.continueWithTask { task -> val meta = task.result if (meta.count == 0) { return@continueWithTask null } val fileMeta = meta.get(0) val file = fileMeta.driveId.asDriveFile() driveResourceClient.openFile(file, DriveFile.MODE_READ_ONLY) }.addOnSuccessListener { driveContents -> val tempInputStream = driveContents.inputStream val inputStream = tempInputStream.copyToByteArrayStream() val outputStream = ByteArrayOutputStream() inputStream.use { input -> outputStream.use { output -> input.copyTo(output) } } val restoreData = String(outputStream.toByteArray(), Charsets.UTF_8) // use this to free resources? driveResourceClient.discardContents(driveContents) } } } }References: