AWS Cognito Sign-In (Android)

Question

I am trying to figure out how to sign in a User with AWS Cognito. The tutorials all seem to deal with Users from a standpoint of signing up Users, not signing them in. I do

Answer 1

It's a bit confusing how the flow works. As @Ionut Trestian explains we need to create what seems to be a blank user from the pool and then authenticate that user. APIs have changed a bit, this are the updated methods.

   CognitoUserPool userPool = new CognitoUserPool(context, userPoolId, clientId, clientSecret, region;
//OR if using awsconfiguration.json
//    CognitoUserPool userPool = new CognitoUserPool(context, AWSMobileClient.getInstance().getConfiguration());

AuthenticationDetails authDetails = new AuthenticationDetails(username, password, null);

CognitoUser user = userPool.getUser();

//You might want do to the following bit inside a thread as it should be done in background
user.initiateUserAuthentication(authDetails, authHandler, true).run();

Answer 2

Cognito User Pools seem to be what you want in your app. What Cognito User Pools does is it gives you a user directory that stores user attribute data and can be used to authenticate against with username and password by your mobile app/website.

Cognito Federated Identities lets you federate users from Facebook, Google, even Cognito User Pools above for the purpose of obtaining AWS credentials to access AWS resources.

From your use case, it seems that you want to create and confirm the users from the admin side, a functionality that Cognito provides by using the adminCreateUser API. After that, the users can sign in by using username and password by using the example 6 in the tutorial you linked.

You can create an empty CognitoUser by calling getUser() on an initialized UserPool.

Code:

    user = userPool.getUser();
    AuthenticationDetails authenticationDetails = new AuthenticationDetails(email, password, null);
    user.authenticateUserInBackground(authenticationDetails, authenticationHandler);

Answer 3

If the registration is done by the office and user get their username and password, so it seems you need to get the users from Cognito User Pool. For authenticating the user in Android App, first, you will need the following configuration from Cognito User Pool:

• Pool Id
• App client id
• App client secret
• AWS Region

Then you should create an instance of the user pool in your app by using CognitoUserPool, like follow:

userPool = new CognitoUserPool(context, this.poolID, this.clientID, this.clientSecret, this.awsRegion);

For allowing the user to sign-in, do the following:

public void getUser(){
    CognitoUser cognitoUser =  userPool.getUser(userId);
    cognitoUser.getSessionInBackground(authenticationHandler);
}
AuthenticationHandler authenticationHandler = new AuthenticationHandler() {
    @Override
    public void authenticationChallenge(ChallengeContinuation continuation) {
      // Do Something
    }
    @Override
    public void onSuccess(CognitoUserSession userSession, CognitoDevice newDevice) {
        Toast.makeText(appContext,"Sign in success", Toast.LENGTH_LONG).show();
        // Do Something
    }
    @Override
    public void getAuthenticationDetails(AuthenticationContinuation authenticationContinuation, String userId) {
        // The API needs user sign-in credentials to continue
        AuthenticationDetails authenticationDetails = new AuthenticationDetails(userId, userPassword, null);
        // Pass the user sign-in credentials to the continuation
        authenticationContinuation.setAuthenticationDetails(authenticationDetails);
        // Allow the sign-in to continue
        authenticationContinuation.continueTask();
    }
    @Override
    public void getMFACode(MultiFactorAuthenticationContinuation multiFactorAuthenticationContinuation) {
      // Do Something
    }
    @Override
    public void onFailure(Exception exception) {
      // Do Something
    }
};

You can find more information about integrating user sign-in and sign-up here and here.