The main Activity outlined in the blog post.

AuthActivity.java

import android.accounts.Account;
import android.accounts.AccountManager;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Toast;
 
import com.google.android.gms.auth.GoogleAuthUtil;
import com.google.android.gms.common.AccountPicker;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
 
public class AuthActivity extends Activity {
 
  static final int REQUEST_CODE_RECOVER_PLAY_SERVICES = 1001;
  static final int REQUEST_CODE_PICK_ACCOUNT = 1002;
 
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
  }
 
  @Override
  protected void onResume() {
    super.onResume();
    if (checkPlayServices() && checkUserAccount()) {
      // Then we're good to go!
    }
  }
 
  private boolean checkPlayServices() {
    int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
    if (status != ConnectionResult.SUCCESS) {
      if (GooglePlayServicesUtil.isUserRecoverableError(status)) {
        showErrorDialog(status);
      } else {
        Toast.makeText(this, "This device is not supported.", Toast.LENGTH_LONG).show();
        finish();
      }
      return false;
    }
    return true;
  }
 
  void showErrorDialog(int code) {
    GooglePlayServicesUtil.getErrorDialog(code, this, REQUEST_CODE_RECOVER_PLAY_SERVICES).show();
  }
 
  private boolean checkUserAccount() {
    String accountName = AccountUtils.getAccountName(this);
    if (accountName == null) {
      // Then the user was not found in the SharedPreferences. Either the
      // application deliberately removed the account, or the application's
      // data has been forcefully erased.
      showAccountPicker();
      return false;
    }
 
    Account account = AccountUtils.getGoogleAccountByName(this, accountName);
    if (account == null) {
      // Then the account has since been removed.
      AccountUtils.removeAccount(this);
      showAccountPicker();
      return false;
    }
 
    return true;
  }
 
  private void showAccountPicker() {
    Intent pickAccountIntent = AccountPicker.newChooseAccountIntent(null, null,
        new String[] { GoogleAuthUtil.GOOGLE_ACCOUNT_TYPE }, true, null, null, null, null);
    startActivityForResult(pickAccountIntent, REQUEST_CODE_PICK_ACCOUNT);
  }
 
  @Override
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
      case REQUEST_CODE_RECOVER_PLAY_SERVICES:
        if (resultCode == RESULT_CANCELED) {
          Toast.makeText(this, "Google Play Services must be installed and up-to-date.",
              Toast.LENGTH_SHORT).show();
          finish();
        }
        return;
      case REQUEST_CODE_PICK_ACCOUNT:
        if (resultCode == RESULT_OK) {
          String accountName = data.getStringExtra(AccountManager.KEY_ACCOUNT_NAME);
          AccountUtils.setAccountName(this, accountName);
        } else if (resultCode == RESULT_CANCELED) {
          Toast.makeText(this, "This application requires a Google account.", 
              Toast.LENGTH_SHORT).show();
          finish();
        }
        return;
    }
    super.onActivityResult(requestCode, resultCode, data);
  }
}

Hi Alex,

Thanks for this, very useful.

I initially found it through a gist search, and then spent a while hunting for your blog. Might be worth adding a pointer to help people find the relevant blog post on the description in gist - something like "The main activity outlined in the blog post: http://www.androiddesignpatterns.com/2013/01/google-play-services-setup.html".

Cheers,

Richard