android-demos | Examples of Android applications | Learning library

For my App I need to have a List sync with Google Drive. I have already implemented the SignIn and had my Main_Activity implement both:

I know from the sample code how to upload a text file into the Drive AppFolder, but from the docs is not clear how to extend it to JSON, if it's possible at all.

Here is the code for uploading a Text File:

I need to copy a file to Google Drive from Android App. Consider copying 4-5 MB file size to root folder.

Have gone through some sample code from here.

Can someone please check below flow and let me know if this is the best approach. I doubt because with this approach

1) have to use many callbacks , which makes code logic less straight forward

2) instead of having a copy like API method, using outputStreamwriter.write() method for file copy operation

Am not saying demo I have gone through is not correct, but don't want to miss any better approach, if exists around.. it is also possible I overlooked something..and picked up wrong example..

Here is the flow I found, and want to check with some Google Drive API expert..

1) After user authorization and connection : call newDriveContents API

Drive.DriveApi.newDriveContents(getGoogleApiClient()).setResultCallback(driveContentsCallback);

2) DriveContentsResult Callback - Call create file , and use output stream write to create or copy files Drive.DriveApi.getRootFolder(getGoogleApiClient()).createFile(getGoogleApiClient(), changeSet, driveContents).setResultCallback(fileCallback);

driveContents will come from OutputStreamWriter.write ( file contents )

3) DriveFileResult Callback - to check sucess or failure Drive.DriveApi.getRootFolder(getGoogleApiClient()).createFile(getGoogleApiClient(), changeSet, driveContents).setResultCallback(fileCallback);

Note : I haven't used try/catch and new Thread() { } in above pseudocode to just make it small and readable ...

I have tried 6+ Example Project but all the project give this same response: