Updating Google Drive Files from an Android App

I want to save data generated by my Android App as a file on Google Drive.

Setting up the environment for the first time
First, I needed the google play services library, which I setup using this guide.  I used the "Android SDK Manager" from Eclipse to download the SDK.  This took a while to complete, because installation of one item required an upgrade or installation of a few other dependent libraries and tools.  In all, it took me about an hour.

I then followed this guide to update my Android project to work with the Google Play Services and Drive API.  At this point, I should have been able to:

• Connect your app to Google Drive.
• Ask you which account you'd like to use.
• Allow you to save a picture that you take to Google Drive.

Of course, things didn't work right out of the box.  Here are the issues I encountered.

• My app was crashing with a message about "No Activity found to handle Intent { act=com.google.android.gms.common.account.CHOOSE_ACCOUNT (has extras) }".  As suggested by a stack overflow question, I tried running my app on a real phone (instead of with an emulator) and it worked without crashing.
• When I tried to save a file to Google drive I got a 403 error with a meesage about "Access Not Configured".  I realized I set up a client id using the production version of my keystore.  I had to use the development version from eclipse with:
  keytool -exportcert -alias androiddebugkey -keystore .android/debug.keystore -list -v
  where the password was 'android'.

My business logic

For my app, I'd like to.

1. Create a new csv (spreadsheet) file on Google Drive.
2. Check if a previously saved file from my app exists on Google Drive, and read it.
3. If a file exists, update the existing csv file with updated data.

1. Creating a new Google Drive Spreadsheet file.
After creating a comma separated file, I saved it to Google Drive with the function listed below.  Importantly, you have to call setConvert(true) in order to allow Google Drive to update the file.

private String m_filename = "someFile";
private void saveFileToDrive() {
    Thread t = new Thread(new Runnable() {
    @Override
    public void run() {
        try {
            // File's metadata.
            File body = new File();
            body.setTitle(m_filename);
            body.setDescription("Description for "+m_filename);
            body.setMimeType("text/csv");
           
            // File's content 
            String filePath = getApplicationContext().getFilesDir() + 
                              java.io.File.separator + 
                              m_filename;
            java.io.File fileContent = new java.io.File(filePath);
            FileContent mediaContent = new FileContent("test/csv",
                                                       fileContent);

            // Insert and convert to spreadsheet
            Insert request = m_service.files().insert(body, mediaContent);
            request.setConvert( true );
     File file = request.execute();
     if (file != null) {
         Log.i("MyTag","saveFileToDrive file Id:"+file.getId());
            }
        } catch (UserRecoverableAuthIOException e) {
            startActivityForResult(e.getIntent(), REQUEST_AUTHORIZATION);
        } catch (GoogleJsonResponseException e) {
            GoogleJsonError error = e.getDetails();

            Log.e("MyTag","Error code: " + error.getCode());
            Log.e("MyTag","Error message: " + error.getMessage());
        }  catch (IOException e) {
            Log.e("MyTag","saveFileToDrive failed");
     e.printStackTrace();
        }
    }});
    t.start();
}