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

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.