Google Sign-In with Credential Manager for Delphi/FMX/Android

TSignInWithGoogle is a straightforward library/component that enables Google Sign-in using Android's Credential Manager in a Object Pascal/Delphi environment, adhering to Google's most recent guidelines.

Requirements

• Delphi Athens +12x
• Binary (JAR/AAR) Dependencies
• Android SDK API Level +33
• Set up your Google Identity APIs console project - API Console

Installing

• Add the TSignInWithGoogle folder path to your project in the menu: Project-> Options-> Delphi Compiler-> Search Path.
• Add all *.jar files located inside the JAR-dependencies folder to your project. From the right side panel: Target Platforms -> Android -> Libraries. Right click and select Add..

Usage - Code Examples

1. Add the SignInWithGoogle unit to your project's uses clause:

   uses
     SignInWithGoogle;

2. Create an instance of TSignInWithGoogle and assign the events:

   var
   SignInWithGoogle: TSignInWithGoogle;
   
   SignInWithGoogle := TSignInWithGoogle.Create(Self);
     with SignInWithGoogle do
      begin
       SetGoogleClientID('xxxxxxxxx-xxxxxx.apps.googleusercontent.com');  
       OnClearStateCredentialSuccessfully:= Self.OnClearStateCredentialSuccessfully;
       OnClearStateCredentialException := Self.OnClearStateCredentialException;      
       OnSignInException := Self.OnSignInException;
       OnSignInSuccessfully := Self.OnSignInSuccessfully;    
      end;

3. Get Credential (Classic Modal UI) for SignInWithGoogle Button

   with SignInWithGoogle do
   begin        
     BuildSignInWithGoogleButton;
     GetCredential;
   end;

4. Or Get Credential (Credential Manager's bottom sheet UI)

   with SignInWithGoogle do
   begin        
     BuildSignInGoogleOptions(False, False)
     GetCredential;
   end;

5. Clear Credential State

   with SignInWithGoogle do
   begin              
    ClearCredentialState; 
   end;

Methods

• SetGoogleClientID(ClientID: String): (Required): Sets the Google Client ID obtained from the credentials manager in the Google Console. You can download it as a JSON file in the configuration. Make sure it's the identifier type 3 (Web) and not type 1 (Android). More details can be found here

• SetNonce(hashNonce: String): Assigns the provided string as a Nonce identifier. If not called, an automatic Nonce hash will be created.

• GetNonce: String: Retrieves the automatically generated Nonce hash. If the nonce was provided by the user, it returns the same string.

• BuildSignInWithGoogleButton: Generates options for calling the SignInWithGoogle button (modal UI).

• BuildSignInGoogleOptions(setFilterByAuthorizedAccounts: Boolean; setAutoSelectEnabled: Boolean): Generates options for the bottom DataSheet. Parameters:

  • setFilterByAuthorizedAccounts: Displays authorized Google accounts if set to True.
  • setAutoSelectEnabled: Enables automatic login. More details can be found here

• GetCredential: Calls the credentials window (asynchronous).

• ClearCredentialState: Clears the stored credential state (asynchronous).

• EnabledDebugging(Flag: Boolean): (for debugging purposes): Activates debug messages visible in LogCat or other log viewers.

Events

• OnSignInSuccessfully: Triggered when the user successfully signs in.
• OnSignInException: Handles exceptions during the sign-in process.
• OnClearStateCredentialSuccessfully: Fired when the credential state is cleared successfully.
• OnClearStateCredentialException: Handles exceptions when clearing the credential state.

• OnSignInSuccessfully = procedure (Sender: TObject; Result: TSignInResult): Receives a record with user login information.
• OnSignInException = procedure (Sender: TObject; Error: Exception; Status: TSignInErrorStatus): Receives an Exception object and a status.
• OnClearStateCredentialSuccesfully = procedure (Sender: TObject;): it does not receive parameters.
• OnClearStateCredentialException = procedure (Sender: TObject; Error: Exception): Receives an Exception object.

AndroidManifest.template.xml

Make sure this line identifying the Google Play service is present in your manifest. Delphi does not always add this metadata tag.

<meta-data android:name="com.google.android.gms.version" android:value="12451000" />

Just below the <%uses-libraries%> add this tag block to activate the Credential Provider Meta Service:

<%uses-libraries%>
 <service android:name="androidx.credentials.playservices.CredentialProviderMetadataHolder"
  android:enabled="true"
  android:exported="false">
 <meta-data  
  android:name="androidx.credentials.CREDENTIAL_PROVIDER_KEY"
  android:value="androidx.credentials.playservices.CredentialProviderPlayServicesImpl"/>
 </service>

Also below the above block another tag block should be added to start the Google UI activity.

 <activity
  android:name="androidx.credentials.playservices.HiddenActivity"
  android:configChanges="orientation|keyboardHidden|screenSize|screenLayout"
  android:enabled="true"
  android:exported="false"
  android:resizeableActivity="true"            
  android:theme="@style/SignInUITheme"
  android:fitsSystemWindows="true">            
  </activity>

The following tag blocks can be bypassed by placing android:theme="@style/SignInUITheme" --> android:theme="@null" but you may experience visual issues and window scrolling when launching the Google UI in your app on FMX.

From Project-> Deployment you can manage the location of these files for Debug and Release.

Add the following to your project's styles-v31.xml file:

<resources xmlns:android="http://schemas.android.com/apk/res/android">
    
    <!-- Default Delphi Resource -->
    <style name="AppTheme" parent="@android:style/Theme.Material.Light.NoActionBar">
        <item name="android:windowBackground">@color/splash_background</item>
        <item name="android:windowClipToOutline">false</item>       
        <!-- API 31+ specific attributes -->
        <item name="android:windowSplashScreenBackground">@color/splash_background</item>
        <item name="android:windowSplashScreenAnimatedIcon">@drawable/splash_vector</item>
        <item name="android:windowSplashScreenIconBackgroundColor">@color/splash_background</item>
    </style>

<!-- You just have to copy this part -->
<style name="SignInUITheme" parent="@android:style/Theme.Material.Light.NoActionBar">
    <item name="android:windowIsTranslucent">true</item>
    <item name="android:windowBackground">@android:color/transparent</item>
    <item name="android:windowContentOverlay">@null</item>
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowIsFloating">false</item>
    <item name="android:backgroundDimEnabled">true</item>
    <item name="android:windowTranslucentStatus">true</item>
    <item name="android:windowTranslucentNavigation">true</item>
</style>
<!-- You just have to copy this part -->

</resources>

Now add the following to your project's styles-v21.xml file:

<resources xmlns:android="http://schemas.android.com/apk/res/android">

    <!-- Default Delphi Resource -->
    <style name="AppTheme" parent="@android:style/Theme.Material.Light.NoActionBar">
        <item name="android:windowBackground">@drawable/splash_image_def</item>
        <item name="android:windowClipToOutline">false</item>
    </style>
   
   <!-- You just have to copy this part -->
   <style name="SignInUITheme" parent="@android:style/Theme.Material.Light.NoActionBar">
    <item name="android:windowIsTranslucent">true</item>
    <item name="android:windowBackground">@android:color/transparent</item>
    <item name="android:windowContentOverlay">@null</item>
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowIsFloating">false</item>
    <item name="android:backgroundDimEnabled">true</item>
    <item name="android:windowTranslucentStatus">true</item>
    <item name="android:windowTranslucentNavigation">true</item>
 </style>
 <!-- You just have to copy this part -->
</resources>

Known Issues

• The OnSignInException event always fires, with the message: "the activity was canceled by the user", this is an issue related to setting up credentials in the Google console. Verify that the client ID is type 3 and that your application's SHA-1 signing is configured correctly in your account. Additionally, OAuth consent screen page must be configured correctly for use.

• The OnSignInException event fires with the message: "failed to launch the selector UI, Hint: ensure the 'context' parameter is an activity-based context". This error appears if a valid activity is not defined to start the credentials window. Make sure you add the hidden activity block for Google UI in your manifest file as described above.

• The OnSignInException event fires with the message: "GetCredentialAsync no provider dependencies found - please ensure the desired provider dependencies are added." Make sure you add the service provider credentials in your manifest file and also the dependencies of the jar/aar files in your project.

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