Make the email login button optional

This was requested by a DPE who is preparing the IO demo.

Change-Id: Ia119aa87bf783d256dbee24bc9ca3e5de9def3ee

Author: Aaron Mandle

auth/src/main/java/com/firebase/ui/auth/AuthFlowFactory.java

@@ -16,6 +16,7 @@
 
 import android.content.Context;
 import android.content.Intent;
+import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 
@@ -24,6 +25,7 @@
 import com.firebase.ui.auth.choreographer.idp.provider.IDPProviderParcel;
 import com.firebase.ui.auth.ui.credentials.CredentialsInitActivity;
 import com.google.firebase.FirebaseApp;
+import com.google.firebase.auth.EmailAuthProvider;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -32,6 +34,10 @@
  * Factory class to configure the intent that starts the auth flow
  */
 public class AuthFlowFactory {
+    public static final String EMAIL_PROVIDER = "email";
+    public static final String GOOGLE_PROVIDER = "google";
+    public static final String FACEBOOK_PROVIDER = "facebook";
+
     /**
      * Creates the intent that starts the auth flow
      *
@@ -73,12 +79,16 @@ public static Intent createIntent(
         }
 
         for (String provider : providers) {
-            if (provider.equalsIgnoreCase("facebook")) {
+            if (provider.equalsIgnoreCase(FACEBOOK_PROVIDER)) {
                 providerParcels.add(FacebookProvider.createFacebookParcel(
                         context.getString(R.string.facebook_application_id)));
-            } else if (provider.equalsIgnoreCase("google")) {
+            } else if (provider.equalsIgnoreCase(GOOGLE_PROVIDER)) {
                 providerParcels.add(
                         GoogleProvider.createParcel(context.getString(R.string.default_web_client_id)));
+            } else if (provider.equalsIgnoreCase(EMAIL_PROVIDER)) {
+                providerParcels.add(
+                        new IDPProviderParcel(EmailAuthProvider.PROVIDER_ID, new Bundle())
+                );
             }
         }
         return CredentialsInitActivity.createIntent(

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

@@ -31,6 +31,7 @@
 import com.firebase.ui.auth.choreographer.idp.provider.IDPProvider;
 import com.firebase.ui.auth.choreographer.idp.provider.IDPProviderParcel;
 import com.firebase.ui.auth.choreographer.idp.provider.IDPResponse;
+import com.google.firebase.auth.EmailAuthProvider;
 import com.google.firebase.auth.FacebookAuthProvider;
 import com.google.firebase.auth.GoogleAuthProvider;
 
@@ -73,6 +74,9 @@ private void populateIDPList(ArrayList<IDPProviderParcel> mProviders) {
                 case GoogleAuthProvider.PROVIDER_ID:
                     mIDPProviders.add(new GoogleProvider(this, providerParcel));
                     break;
+                case EmailAuthProvider.PROVIDER_ID:
+                    findViewById(R.id.email_provider).setVisibility(View.VISIBLE);
+                    break;
                 default:
                     if (BuildConfig.DEBUG) {
                         Log.d(TAG, "Encountered unknown IDPProvider parcel with type: "

auth/src/main/res/values/styles.xml

@@ -215,6 +215,7 @@
 
     <style name="FirebaseUI.Button.AccountChooser.EmailButton">
         <item name="android:drawableLeft">@drawable/ic_email_white_18dp</item>
+        <item name="android:visibility">gone</item>
         <item name="android:background">@drawable/idp_button_background_email</item>
         <item name="android:textColor">#ffffff</item>
     </style>