Fix for using custom Layout icm Email Link (#1661)

Author: Entreco

auth/src/main/java/com/firebase/ui/auth/ui/idp/AuthMethodPickerActivity.java

@@ -206,7 +206,8 @@ private void populateIdpList(List<IdpConfig> providerConfigs) {
     private void populateIdpListCustomLayout(List<IdpConfig> providerConfigs) {
         Map<String, Integer> providerButtonIds = customLayout.getProvidersButton();
         for (IdpConfig idpConfig : providerConfigs) {
-            final String providerId = idpConfig.getProviderId();
+            final String providerId = providerOrEmailLinkProvider(idpConfig.getProviderId());
+
             if (!providerButtonIds.containsKey(providerId)) {
                 throw new IllegalStateException("No button found for auth provider: " + providerId);
             }
@@ -217,6 +218,15 @@ private void populateIdpListCustomLayout(List<IdpConfig> providerConfigs) {
         }
     }
 
+    @NonNull
+    private String providerOrEmailLinkProvider(@NonNull String providerId) {
+        if (providerId.equals(EmailAuthProvider.EMAIL_LINK_SIGN_IN_METHOD)) {
+            return EmailAuthProvider.PROVIDER_ID;
+        }
+
+        return providerId;
+    }
+
     private void handleSignInOperation(IdpConfig idpConfig, View view) {
         ViewModelProvider supplier = ViewModelProviders.of(this);
         final String providerId = idpConfig.getProviderId();

auth/src/test/java/com/firebase/ui/auth/ui/idp/AuthMethodPickerActivityTest.java

@@ -122,6 +122,28 @@ public void testCustomAuthMethodPickerLayout() {
                 nextIntent.intent.getComponent().getClassName());
     }
 
+    @Test
+    public void testCustomAuthMethodPickerLayoutWithEmailLink() {
+        List<String> providers = Arrays.asList(EmailAuthProvider.EMAIL_LINK_SIGN_IN_METHOD);
+
+        AuthMethodPickerLayout customLayout = new AuthMethodPickerLayout
+                .Builder(R.layout.fui_provider_button_email)
+                .setEmailButtonId(R.id.email_button)
+                .build();
+
+        AuthMethodPickerActivity authMethodPickerActivity = createActivityWithCustomLayout(providers, customLayout);
+
+        Button emailButton = authMethodPickerActivity.findViewById(R.id.email_button);
+        emailButton.performClick();
+
+        //Expected result -> Directing users to EmailActivity
+        ShadowActivity.IntentForResult nextIntent =
+                Shadows.shadowOf(authMethodPickerActivity).getNextStartedActivityForResult();
+        assertEquals(
+                EmailActivity.class.getName(),
+                nextIntent.intent.getComponent().getClassName());
+    }
+
     private AuthMethodPickerActivity createActivityWithCustomLayout(List<String> providers,
                                                                     AuthMethodPickerLayout layout) {
         Intent startIntent = AuthMethodPickerActivity.createIntent(