Android账号管理机制

这个Service会在onBind方法里返回一个IBinder给客户端进程，如下：

    @Override
    public IBinder onBind(Intent intent) {
        if (Log.isLoggable(TAG, Log.VERBOSE)) {
            Log.v(TAG, "getBinder()...  returning the AccountAuthenticator binder for intent "
                    + intent);
        }
        return mAuthenticator.getIBinder();
    }

//当在“设置”中添加账号时，会调用这个方法，跳转到添加账号页面
@Override
    public Bundle addAccount(AccountAuthenticatorResponse response, String accountType,
            String authTokenType, String[] requiredFeatures, Bundle options) {
        Log.v(TAG, "addAccount()");
 //指定AuthenticatorActivity为添加账号的页面，下面会介绍。
        final Intent intent = new Intent(mContext, AuthenticatorActivity.class);
        intent.putExtra(AccountManager.KEY_ACCOUNT_AUTHENTICATOR_RESPONSE, response);
        final Bundle bundle = new Bundle();
        bundle.putParcelable(AccountManager.KEY_INTENT, intent);
        return bundle;
    }




//当执行mAccountManager.blockingGetAuthToken(account,Constants.AUTHTOKEN_TYPE, NOTIFY_AUTH_FAILURE);时调用该方法。
    @Override
    public Bundle getAuthToken(AccountAuthenticatorResponse response, Account account,
            String authTokenType, Bundle loginOptions) throws NetworkErrorException {
        Log.v(TAG, "getAuthToken()");
// 通过blockingGetAuthToken方法传来的Constants.AUTHTOKEN_TYPE
        if (!authTokenType.equals(Constants.AUTHTOKEN_TYPE)) {
            final Bundle result = new Bundle();
            result.putString(AccountManager.KEY_ERROR_MESSAGE, "invalid authTokenType");
            return result;
        }
final AccountManager am = AccountManager.get(mContext);
        final String password = am.getPassword(account);
        if (password != null) {
            final String authToken = NetworkUtilities.authenticate(account.name, password);
            if (!TextUtils.isEmpty(authToken)) {
  //如果已经到服务器验证过账号并保存到AccountManager中
                final Bundle result = new Bundle();
                result.putString(AccountManager.KEY_ACCOUNT_NAME, account.name);
                result.putString(AccountManager.KEY_ACCOUNT_TYPE, Constants.ACCOUNT_TYPE);
                result.putString(AccountManager.KEY_AUTHTOKEN, authToken);
                return result;
            }
        }
//如果没有到服务器验证过账号并保存到AccountManager中，则重新倒添加账号页面中验证。
        final Intent intent = new Intent(mContext, AuthenticatorActivity.class);
        intent.putExtra(AuthenticatorActivity.PARAM_USERNAME, account.name);
        intent.putExtra(AuthenticatorActivity.PARAM_AUTHTOKEN_TYPE, authTokenType);
        intent.putExtra(AccountManager.KEY_ACCOUNT_AUTHENTICATOR_RESPONSE, response);
        final Bundle bundle = new Bundle();
        bundle.putParcelable(AccountManager.KEY_INTENT, intent);
        return bundle;
    }

/**
     * Called when response is received from the server for authentication
     * request. See onAuthenticationResult(). Sets the
     * AccountAuthenticatorResult which is sent back to the caller. We store the
     * authToken that&＃39;s returned from the server as the &＃39;password&＃39; for this
     * account - so we&＃39;re never storing the user&＃39;s actual password locally.
     *
     * @param result the confirmCredentials result.
     */
    private void finishLogin(String authToken) {
Log.i(TAG, "finishLogin()");
        final Account account = new Account(mUsername, Constants.ACCOUNT_TYPE);
        if (mRequestNewAccount) {
     //直接向AccountManager添加一个帐户
            mAccountManager.addAccountExplicitly(account, mPassword, null);
            //设置让这个账号能够自动同步
            ContentResolver.setSyncAutomatically(account, ContactsContract.AUTHORITY, true);
        } else {
            mAccountManager.setPassword(account, mPassword);
        }
        final Intent intent = new Intent();
        intent.putExtra(AccountManager.KEY_ACCOUNT_NAME, mUsername);
        intent.putExtra(AccountManager.KEY_ACCOUNT_TYPE, Constants.ACCOUNT_TYPE);
        setAccountAuthenticatorResult(intent.getExtras());
        setResult(RESULT_OK, intent);
        finish();
    }