Login with Amazon Getting Started Guide for Android

Add Your API Key to Your Project

When you register your Android application with Login with Amazon, you are assigned an API key. This is an identifier that the Amazon Authorization Manager will use to identify your application to the Login with Amazon authorization service. If you are using the Amazon Appstore to sign your app, the Appstore will provide the API key automatically. If you are not using the Amazon Appstore, the Amazon Authorization Manager loads this value at runtime from the api_key.txt file in the assets directory.

1. If you do not have your API Key yet, follow the instructions in Retrieve the Android API Key (p. 11).
2. With your ADT project open, from the File menu, click New and select Untitled Text File. You should now have an editor window for a text file named Untitled 1. Add your API key to the text
3. From the File menu, click Save As.
4. In the Save As dialog, select the assets directory of your project as the parent folder. For File name , enter txt.

Remove the Sample App Custom Debug Keystore

**NOTE** : This step is required only if you are using Eclipse; if you are using Android Studio, skip this section.

If you installed the Login with Amazon for Android sample application into the same workspace you are using for your Android app, you may have a custom debug keystore set for the workspace. You need to clear the custom debug keystore in order to use your own API key.

1. From the main menu, click Window and select Preferences.
2. In the Preferences dialog, select Android and Build.
3. Clear the Custom debug keystore
4. Click OK.

Handle Configuration Changes for Your Activity

If a user changes the screen orientation or changes the keyboard state of the device while they are logging in, it will prompt a restart of the current activity. This restart will dismiss the login screen unexpectedly. To prevent this, you should set the activity that uses the authorize method to handle those configuration changes manually. This will prevent a restart of the activity.

1. In Package Explorer , double-click xml.
2. In the Application section, locate the activity that will handle Login with Amazon (for example, MainActivity ).

3. Add the following attribute to the activity you located in Step 2:
   android:configChanges=”keyboard|keyboardHidden|orientation”

Or for API 13 or greater:

android:configChanges=”keyboard|keyboardHidden|orientation|screenSize”

4.  From the File menu, click Save
   Now, when a keyboard or device orientation change happens, Android will call the onConfigurationChanged method for your activity. You do not need to implement this function unless there is an aspect of these configuration changes that you want to handle for your app

Add an Authorization Activity to Your Project

When the user clicks the Login with Amazon button, the API will launch a web browser to present a login and consent page to the user. In order for this browser activity to work, you must add the AuthorizationActivity to your manifest.

1. In Package Explorer , double-click xml.
2. In the Application section, add the following code, replacing “com.example.app” with your package name for this app:
   <activity android:name=
   “com.amazon.identity.auth.device.authorization.AuthorizationActivity” android:theme=”@android:style/Theme.NoDisplay” android:allowTaskReparenting=”true” android:launchMode=”singleTask”><intent- filter> ---

Add a Login with Amazon Button to Your App

your app. This section gives steps for downloading an official Login with Amazon image and pairing it with an Android ImageButton.

1. Add a standard ImageButton to your app.
   For more information on Android buttons and the ImageButton class, see Buttons on developer.android.com.

2. Give your button an id.
   In the button XML declaration, set the android:id attribute to @+id/login_with_amazon. For example:android:id=”@+id/login_with_amazon”

3. Choose a button image.
   Consult our Login with Amazon Style Guidelines for a list of buttons that you can use in your app. Download a copy of the LWA_Android.zip file. Extract a copy of your preferred button for each screen density your app supports (xxhdpi, xhdpi, hdpi, mdpi, or tvdpi). For more information on supporting multiple screen densities in Android, see Alternative Layouts in the “Supporting Multiple Screens” topic ondeveloper.android.com.

4. Copy the appropriate button image files to your project.
   For each screen density that you support (xhdpi, hdpi, mdpi, or ldpi), copy the downloaded button to the res/drawable directory for that screen density.

5. Declare the button image.
   In the button XML declaration, set the android:src attribute to the name of the button you have chosen. For example:android:src=”@drawable/btnlwa_gold_loginwithamazon.png”

6. Load your app, and verify that the button now has a Login with Amazon image. You should verify that the button displays properly for each screen density you support.

Handle the Login Button and Get Profile Data

This section explains how to call the authorize and getProfile APIs to log in a user and retrieve their profile data. This includes creating an onClick listener for your Login with Amazon button in the onCreate method of your app.

1. Add Login with Amazon to your Android project. See Install the Login with Amazon Library.

2. Import the Login with Amazon API to your source
   To import the Login with Amazon API, add the following import statements to your source file:import com.amazon.identity.auth.device.AuthError; import
   com.amazon.identity.auth.device.authorization.api.
   AmazonAuthorizationManager; import
   com.amazon.identity.auth.device.authorization.api. AuthorizationListener; import com.amazon.identity.auth.device.authorization.api.AuthzConstants;

3. Initialize AmazonAuthorizationManager.
   You will need to declare an AmazonAuthorizationManager variable and create a new instance of the class. Creating a new instance only requires your current application context and an empty bundle. The best place to initialize AmazonAuthorizationManager is in the onCreate method of your Activity. For example:

4. Create an AuthorizeLiistener.
   AuthorizeListener implements the AuthorizatioinListener interface, and will process the result of the authorizecall. It contains three methods: oinSuccess, onError, and onCanceil. Each method receives either a Bundle or an AuthError object.private class AuthorizeListener implements AuthorizationListener{
   / Authorization was completed successfully. /
   @Override
   public void onSuccess(Bundle response) {
   }
   / There was an error during the attempt to authorize the application.
   /
   @Override
   public void onError(AuthError ae) {
   }
   / Authorization was cancelled before it could be completed. /
   @Override
   public void onCancel(Bundle cause) {
   }
   }

5. Call AmazonAuthorizationManager.authorize.
   In the onClick handler for your Login with Amazon button, call authorize to prompt the user to log in and authorize your application.
   This method is responsible for authorizing the customer in one of the following ways:

6. Switches to the system browser and lets the customer sign in and consent to the requested

7. Switches to web view in a secure context, to let the customer sign in and consent to the requested

This secure context for #2 is currently made available as the Amazon Shopping app on Android devices. Amazon-created devices running Fire OS (for example Kindle Fire, Fire Phone, and Fire TV) always use this option even if there is no Amazon Shopping app on the device. Because of this, if the customer is already signed in to the Amazon Shopping app, this API will skip the sign- in page, leading to a Single Sign On experience for the customer.
When your application is authorized, it is authorized for one or more data sets known as scopes. The first parameter is an array of scopes that encompass the user data that you are requesting from Login with Amazon. The first time a user logs in to your app, they will be presented with a list of the data you are requesting and asked for approval. Login with Amazon currently supports three scopes: profile, which contains the user’s name, email address, and Amazon account id; _profile:userid, which contains only the Amazon account id; and _postalcode, which contains the user’s zip/postal code.
The best way to call authorize is asynchronously, so you do not have to block the UI thread or create a worker thread of your own. To call authorizeasynchronously, pass an object that supports the AuthorizationListenerinterface as the last parameter:

private AmazonAuthorizationManager mAuthManager;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mAuthManager = new AmazonAuthorizationManager(this, Bundle.EMPTY);

// Find the button with the login_with_amazon ID
// and set up a click handler
mLoginButton = (Button) findViewById(R.id.login_with_amazon);
mLoginButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mAuthManager.authorize(
new String []{“profile”,”postal_code”},
Bundle.EMPTY, new AuthorizeListener());
}
});
}

6. Create a ProfileListener.
   ProfileListener is our name for a class that implements the APIListener interface, and will process the result of the getProfile call. APIListener contains two methods: onSuccess and onError (it does not support onCancel because there is no way to cancel a getProfile call). onSuccess receives a Bundle object with profile data, while onEriror receives an AuthError object with information on the error.private class ProfileListener implements APIListener{

/ getProfile completed successfully. / @Override
public void onSuccess(Bundle response) {

}
/ There was an error during the attempt to get the profile. / @Override
public void onError(AuthError ae) {
}
}

7. Implement onSuccess for your AuthorizeListener.
   In onSuccess, call AmazonAuthorizationManager.getProfile to retrieve the customer profile. getProfile, like authorize, uses an asynchronous listener interface. For getProfile, that interface is APIListener, notAuthorizationListener.
   / Authorization was completed successfully. / @Override
   public void onSuccess(Bundle response) {
   mAuthManager.getProfile(new ProfileListener());}

8. Implement onSuccessfor your ProfileListener.
   onSuccesshas two main tasks: to retrieve the profile data from the response Bundle, and to pass the data to the UI. updateProfileDatais a hypothetical function your app could implement to display profile details. setLoggedInState, another hypothetical function, would indicate that a user is logged in and give them a means of loggingout.
   To retrieve the profile data from the Bundle, we use names stored by the AuthzConstants class. The onSuccess bundle contains the profile data in a BUNDLE_KEY.PROFILE bundle.
   Within the profile bundle, the scope data is indexed under _PROFILE_KEY.NAME, PROFILE_KEY.EMAIL, PROFILE_KEY.USERID, and _PROFILE_KEY.POSTAL_CODE. PROFILE_KEY.POSTALCODE is only included if you request the _postalcode scope.@Override
   public void onSuccess(Bundle response) {
   // Retrieve the data we need from the Bundle Bundle profileBundle = response.getBundle(
   AuthzConstants.BUNDLE_KEY.PROFILE.val);
   String name = profileBundle.getString(
   AuthzConstants.PROFILE_KEY.NAME.val);
   String email = profileBundle.getString(
   AuthzConstants.PROFILE_KEY.EMAIL.val);
   String account = profileBundle.getString(
   AuthzConstants.PROFILE_KEY.USER_ID.val);
   String zipcode = profileBundle.getString(
   AuthzConstants.PROFILE_KEY.POSTAL_CODE.val);
   runOnUiThread(new Runnable() { @Override
   public void run() {
   updateProfileData(name, email, account, zipcode);
   }
   });
   }

9. Implement onError for your ProfileListener.
   onError includes an AuthError object containing details about the error./ There was an error during the attempt to get the profile. / @Override
   public void onError(AuthError ae) {
   / Retry or inform the user of the error /
   }

10. Implement onErrorfor your AuthorizeListener.
    / There was an error during the attempt to authorize the application.
    /
    @Override
    public void onError(AuthError ae) {
    / Inform the user of the error /
    }

11. Implement onCancelfor your AuthorizeListener.
    Because the authorization process presents a login screen (and possibly a consent screen) to the user in a web browser (or a webview), the user will have an opportunity to cancel the login or navigate away from the web page. If they explicitly cancel the login process, onCancel is called. If onCancelis called, you will want to reset your UI./ Authorization was cancelled before it could be completed. /
    @Override
    public void onCancel(Bundle cause) {
    / reset the UI to a ready-to-login state /
    }

Note: If the user navigates away from the login screen in the browser or web view and switches back to your app, the SDK will not detect that the login was not completed. If you detect user activity in your app before login is completed, you can assume they have navigated away from the browser and react accordingly.

Check for User Login at Startup

If a user logs into your app, closes the app, and restarts the app later, the app is still authorized to retrieve data. The user is not logged out automatically. At startup, you can show the user as logged in if your app is still authorized. This section explains how to use getToken to see if the app is still authorized.

1. Create a TokenListener.
   TokenListener implements the APIListener interface, and will process the result of the getToken call. APIListener contains two methods: onSuccess and onError (it does not support onCancel because there is no way to cancel a getToken call). onSuccess receives a Bundle object with token data, while onError receives an AuthError object with information on the error.private class TokenListener implements APIListener{

/ getToken completed successfully. / @Override
public void onSuccess(Bundle response) {
}
/ There was an error during the attempt to get the token. / @Override
public void onError(AuthError ae) {
}
}

2. In the onStart method of your Activity, call getToken to see if the application is still authorized.
   getToken retrieves the raw access token that the AmazonAuthorizationManager uses to access a customer profile. If the token value is not null, then the app is still authorized and a call to getProfile should succeed. getTokenrequires the same scopes you requested in your call to authorize.
   getTokensupports asynchronous calls in the same manner as getProfile, so you do not have to block the UI thread or create a worker thread of your own. To call getToken asynchronously, pass an object that supports the APIListener interface as the final parameter.@Override
   protected void onStart(){
   super.onStart
   ();mAuthManager.getToken(new String []{“profile”,”postal_code”},
   new
   TokenListener());
   }

3. Implement onSuccess for your TokenListener.
   onSuccesshas two tasks: to retrieve the token from the Bundle, and if the token is valid, to call getProfile.
   To retrieve the token data from the Bundle, we use names stored by the AuthzConstants class. The onSuccess bundle contains the token data in a BUNDLE_KEY.TOKEN value. If that value is not null, this example calls getProfile using the same listener you declared in the previous section (see steps 7 and 8)./ getToken completed successfully. /
   @Override
   public void onSuccess(Bundle response) {
   final String authzToken =
   response.getString(AuthzConstants.BUNDLE_KEY.TOKEN.val);
   if (!TextUtils.isEmpty(authzToken))
   {
   // Retrieve the profile data
   mAuthManager.getProfile(new ProfileListener());
   }
   }

Clear Authorization State and Log Out a User

The clearAuthorizationState method will clear the user’s authorization data from the AmazonAuthorizationManager local data store. A user will have to log in again in order for the app to retrieve profile data. Use this method to log out a user, or to troubleshoot login problems in the app.

1. Implement a logout
   When a user has successfully logged in, you should provide a logout mechanism so they can clear their profile data and previously authorized scopes. Your mechanism might be a hyperlink, or a menu item. For this example we will create an onClick method for a button.

2. In your logout handler, call clearAuthorizationState. clearAuthorizationState will remove a user’s authorization data (access tokens, profile) from the local store. clearAuthorizationStatetakes no parameters except for an APIListener to return success or

3. Declare an anonymous APIListener.
   Anonymous classes are a useful alternative to declaring a new class to implement APIListener. See Handle the Login Button and Get Profile Data (p. 17) for an examplethat declares listener classes.

4. Implement onSuccess inside the APIListener
   When clearAuthorizationState succeeds you should update your UI to remove references to the user, and provide a login mechanism users can use to log in again.

5. Implement onError inside the APIListener.
   If clearAuthorizationStatereturns an error, you can let the user try to log out again.@Override
   protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   / Previous onCreate declarations omitted /
   // Find the button with the logout ID and set up a click handler
   mLogoutButton = (Button) findViewById(R.id.logout);
   mLogoutButton.setOnClickListener(new OnClickListener() {
   @Override
   public void onClick(View v) {
   mAuthManager.clearAuthorizationState(new
   APIListener() {
   @Override
   public void onSuccess(Bundle results) {
   // Set logged out state in UI
   }
   @Override
   public void onError(AuthError authError) {
   // Log the error
   }
   });
   }
   });
   }

Call AmazonAuthorizationManager Methods Synchronously

Some AmazonAuthorizationManager methods return a Future object. This allows you to call the method synchronously instead of passing a listener as a parameter. If you do use a Future object, you should not use it on a UI thread. If you block a UI thread for more than five seconds you will get an ANR (Application Not Responding) prompt. In the Handle the Login Button and Get Profile Data example , the onSuccess method for AuthorizeListener is called with a worker thread created by AmazonAuthorizationManager. This means it is safe to use that thread to call getPirofile synchronously. To make a synchronous call, assign the return value from getPirofile to a Future object, and call the gietmethod on that object to wait until the method completes.

Fuiture.get returns a Bundle object that contains a _FUTURETYPE value of SUCCESS, ERROR, or CANCEL. If the method was a success, the same bundle will contain PROFILE_KEY values for the profile data. For example:

/ Authorization was completed successfully. /
@Override
public void onSuccess(Bundle response) {
Future<Bundle> future = mAuthManager.getProfile(null); Bundle result = future.get();// Find out if the call succeeded, and retrieve the profile Object future_type =
result.get(AuthzConstants.BUNDLE_KEY.FUTURE.val);
if (future_type == AuthzConstants.FUTURE_TYPE.SUCCESS)
{
String name = result.getString( AuthzConstants.PROFILE_KEY.NAME.val);
String email = result.getString( AuthzConstants.PROFILE_KEY.EMAIL.val);
String account = result.getString( AuthzConstants.PROFILE_KEY.USER_ID.val);
String zipcode = result.getString( AuthzConstants.PROFILE_KEY.POSTAL_CODE.val);
runOnUiThread(new Runnable() { @Override
public void run() { updateProfileData(name, email, account,
zipcode);
}
});
}
else if (future_type == AuthzConstants.FUTURE_TYPE.ERROR)
{
// Get error object
AuthError authError = AuthError.extractError(result);
/ Use authError to diagnose error /

}
else if (future_type == AuthzConstants.FUTURE_TYPE.CANCEL)
{
/ User cancelled during authorization /
}
}

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