OpenTracks/MyTracks/src/com/google/android/apps/mytracks/AccountChooser.java

/*
 * Copyright 2010 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.android.apps.mytracks;

import com.google.android.accounts.Account;
import com.google.android.accounts.AccountManager;
import com.google.android.maps.mytracks.R;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.util.Log;

/**
 * Choose which account to upload track information to.
 * @author Sandor Dornbush
 */
public class AccountChooser {
 
  /**
   * The last selected account.
   */
  private int selectedAccountIndex = -1;
  private Account selectedAccount = null;

  /**
   * An interface for receiving updates once the user has selected the account.
   */
  public interface AccountHandler {
    /**
     * Handle the account being selected.
     * @param account The selected account or null if none could be found
     */
    public void handleAccountSelected(Account account);
  }

  /**
   * Chooses the best account to upload to.
   * If no account is found the user will be alerted.
   * If only one account is found that will be used.
   * If multiple accounts are found the user will be allowed to choose.
   * 
   * @param activity The parent activity
   * @param handler The handler to be notified when an account has been selected
   */
  public void chooseAccount(final Activity activity,
      final AccountHandler handler) {
    final Account[] accounts = AccountManager.get(activity)
        .getAccountsByType(MyTracksConstants.ACCOUNT_TYPE);
    if (accounts.length < 1) {
      alertNoAccounts(activity, handler);
      return;
    }
    if (accounts.length == 1) {
      handler.handleAccountSelected(accounts[0]);
      return;
    }
    
    // TODO This should be read out of a preference.
    if (selectedAccount != null) {
      handler.handleAccountSelected(selectedAccount);
      return;
    }
    
    // Let the user choose.
    Log.e(MyTracksConstants.TAG, "Multiple matching accounts found.");
    final AlertDialog.Builder builder = new AlertDialog.Builder(activity);
    builder.setTitle(R.string.choose_account_title);
    builder.setCancelable(false);
    builder.setPositiveButton(R.string.ok,
        new DialogInterface.OnClickListener() {
      public void onClick(DialogInterface dialog, int which) {
        selectedAccount = accounts[selectedAccountIndex];
        handler.handleAccountSelected(selectedAccount);
      }
    });
    builder.setNegativeButton(R.string.cancel,
        new DialogInterface.OnClickListener() {
      public void onClick(DialogInterface dialog, int which) {
        handler.handleAccountSelected(null);
      }
    });
    String[] choices = new String[accounts.length];
    for (int i = 0; i < accounts.length; i++) {
      choices[i] = accounts[i].name;
    }
    builder.setSingleChoiceItems(choices, selectedAccountIndex,
        new DialogInterface.OnClickListener() {
      @Override
      public void onClick(DialogInterface dialog, int which) {
        selectedAccountIndex = which;
      }
    });
    builder.show();
  }

  /**
   * Puts up a dialog alerting the user that no suitable account was found.
   */
  private void alertNoAccounts(final Activity activity,
      final AccountHandler handler) {
    Log.e(MyTracksConstants.TAG, "No matching accounts found.");
    final AlertDialog.Builder builder = new AlertDialog.Builder(activity);
    builder.setTitle(R.string.no_account_found_title);
    builder.setMessage(R.string.no_account_found);
    builder.setCancelable(true);
    builder.setNegativeButton(R.string.ok,
        new DialogInterface.OnClickListener() {
          public void onClick(DialogInterface dialog, int which) {
            handler.handleAccountSelected(null);
          }
        });
    builder.show();
  }
}