Android: how to make my app remember Google Drive Authorization?

Question

I got this code from the Internet and I modified it to upload a specific file automatically to Google Drive when starting the activity. It is always ask me to select my Google account when I start this activity! I want it ask about Google account once only when started for the first time after install it, How to do that?

package com.example.googledrive;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import java.util.Arrays;
import java.io.IOException;
import android.accounts.AccountManager;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.widget.Toast;
import com.google.api.client.extensions.android.http.AndroidHttp;
import com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential;
import com.google.api.client.googleapis.extensions.android.gms.auth.UserRecoverableAuthIOException;
import com.google.api.client.http.FileContent;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.services.drive.Drive;
import com.google.api.services.drive.DriveScopes;
import com.google.api.services.drive.model.File;

public class MainActivity extends Activity {
    static final int                REQUEST_ACCOUNT_PICKER = 1;
    static final int                REQUEST_AUTHORIZATION = 2;
    static final int                REQUEST_DOWNLOAD_FILE = 3;
    static final int                RESULT_STORE_FILE = 4;
    private static Uri              mFileUri;
    private static Drive            mService;
    private GoogleAccountCredential mCredential;
    private Context                 mContext;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        // setup for credentials for connecting to the Google Drive account
        mCredential = GoogleAccountCredential.usingOAuth2(this, Arrays.asList(DriveScopes.DRIVE));

        // start activity that prompts the user for their google drive account
        startActivityForResult(mCredential.newChooseAccountIntent(), REQUEST_ACCOUNT_PICKER);        
       // mContext = getApplicationContext(); 
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu)
    {
        getMenuInflater().inflate(R.menu.main, menu);       
        return true;
    }

    @Override
    protected void onActivityResult(final int requestCode, final int resultCode, final Intent data)
    {
        switch (requestCode) {
            case REQUEST_ACCOUNT_PICKER:
                if (resultCode == RESULT_OK && data != null && data.getExtras() != null) {
                    String accountName = data.getStringExtra(AccountManager.KEY_ACCOUNT_NAME);
                    if (accountName != null) {
                        mCredential.setSelectedAccountName(accountName);
                        mService = getDriveService(mCredential);
                    }
                    saveFileToDrive();
                }
                break;
            case REQUEST_AUTHORIZATION:
                if (resultCode == Activity.RESULT_OK) {
                    //account already picked
                } else {
                    startActivityForResult(mCredential.newChooseAccountIntent(), REQUEST_ACCOUNT_PICKER);
                }
                break;
        }
    }

    private Drive getDriveService(GoogleAccountCredential credential)
    {
        return new Drive.Builder(AndroidHttp.newCompatibleTransport(), new GsonFactory(), credential)
            .build();
    }


    private void saveFileToDrive()
    {
        Thread t = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    // Create URI from real path
                    String path;
                    path = "/sdcard/DCIM/Camera/a.png";
                    mFileUri = Uri.fromFile(new java.io.File(path));

                    ContentResolver cR = MainActivity.this.getContentResolver();

                    // File's binary content
                    java.io.File fileContent = new java.io.File(mFileUri.getPath());
                    FileContent mediaContent = new FileContent(cR.getType(mFileUri), fileContent);

                    showToast("Selected " + mFileUri.getPath() + "to upload");

                    // File's meta data. 
                    File body = new File();
                    body.setTitle(fileContent.getName());
                    body.setMimeType(cR.getType(mFileUri));

                    com.google.api.services.drive.Drive.Files f1 = mService.files();
                    com.google.api.services.drive.Drive.Files.Insert i1 = f1.insert(body, mediaContent);
                    File file = i1.execute();

                    if (file != null) 
                    {
                        showToast("Uploaded: " + file.getTitle());
                    }
                } catch (UserRecoverableAuthIOException e) {
                    startActivityForResult(e.getIntent(), REQUEST_AUTHORIZATION);
                } catch (IOException e) {
                    e.printStackTrace();
                    showToast("Transfer ERROR: " + e.toString());
                }
            }
        });
        t.start();
    }

    public void showToast(final String toast)
    {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(getApplicationContext(), toast, Toast.LENGTH_SHORT).show();
            }
        });
    }

}

Answer 1

It's been a while, so you probably managed to do this by now, but I was just looking for the same thing and it's fairly easy. In the code you use and how it's used on several sites you get an Intent after calling a static method on GoogleAccountCredential.

You can also create your own, by calling a static method on AccountPicker and define a params that it's only required to pick once.

Intent accountPicker = AccountPicker.newChooseAccountIntent(null, null, new String[]{"com.google"}, false, null, null, null, null);
startActivityForResult(accountPicker, GOOGLE_ACCOUNT_PICKED);  

The fourth param is what you want and you can read more about it here: https://developers.google.com/android/reference/com/google/android/gms/common/AccountPicker?hl=en