It's a complex process, but it can be done! I wrote a blog post on getting the basics up and running. And I've also published an open-source project that is actually useful, but still quite minimal. It uses OAuth, and therefore can pull the permission directly from Android's permission model (no hardcoded email/password!).
You need something to start the "Choose account intent":
View.OnTouchListener mDelayHideTouchListener = new View.OnTouchListener() {
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
Intent intent = AccountPicker.newChooseAccountIntent(null, null, new String[]{"com.google"},
false, null, null, null, null);
startActivityForResult(intent, 1);
if (AUTO_HIDE) {
delayedHide(AUTO_HIDE_DELAY_MILLIS);
}
return false;
}
};
And then when that intent returns, you can try to use the token that was returned (although note, if it's the first time the user may have to explicitly authorize your program; that's the UserRecoverableAuthException):
protected void onActivityResult(final int requestCode, final int resultCode,
final Intent data) {
if (requestCode == 1 && resultCode == RESULT_OK) {
final String accountName = data.getStringExtra(AccountManager.KEY_ACCOUNT_NAME);
System.err.println(accountName);
(new AsyncTask<String, String,String>(){
@Override
protected String doInBackground(String... arg0) {
try {
// Turn account name into a token, which must
// be done in a background task, as it contacts
// the network.
String token =
GoogleAuthUtil.getToken(
FullscreenActivity.this,
accountName,
"oauth2:https://spreadsheets.google.com/feeds https://docs.google.com/feeds");
System.err.println("Token: " + token);
// Now that we have the token, can we actually list
// the spreadsheets or anything...
SpreadsheetService s =
new SpreadsheetService("Megabudget");
s.setAuthSubToken(token);
// Define the URL to request. This should never change.
// (Magic URL good for all users.)
URL SPREADSHEET_FEED_URL = new URL(
"https://spreadsheets.google.com/feeds/spreadsheets/private/full");
// Make a request to the API and get all spreadsheets.
SpreadsheetFeed feed;
try {
feed = s.getFeed(SPREADSHEET_FEED_URL, SpreadsheetFeed.class);
List<SpreadsheetEntry> spreadsheets = feed.getEntries();
// Iterate through all of the spreadsheets returned
for (SpreadsheetEntry spreadsheet : spreadsheets) {
// Print the title of this spreadsheet to the screen
System.err.println(spreadsheet.getTitle().getPlainText());
}
} catch (ServiceException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (UserRecoverableAuthException e) {
// This is NECESSARY so the user can say, "yeah I want
// this app to have permission to read my spreadsheet."
Intent recoveryIntent = e.getIntent();
startActivityForResult(recoveryIntent, 2);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (GoogleAuthException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}}).execute();
} else if (requestCode == 2 && resultCode == RESULT_OK) {
// After the user YAYs or NAYs our permission request, we are
// taken here, so if we wanted to grab the token now we could.
}
}
