Merge pull request #872 from tidbeck/bug/apple_button_dark_mode

Make Sign in with Apple button white in dark mode

Author: morganchen12

OAuth/FirebaseOAuthUI/FUIOAuth.m

@@ -79,6 +79,11 @@ @interface FUIOAuth () <ASAuthorizationControllerDelegate, ASAuthorizationContro
  */
 @property(nonatomic, strong) UIColor *buttonBackgroundColor;
 
+/** @property buttonTextColor
+ @brief The text color that should be used for the sign in button of the provider.
+ */
+@property(nonatomic, readwrite) UIColor *buttonTextColor;
+
 /** @property scopes
     @brief Array used to configure the OAuth scopes.
  */
@@ -118,6 +123,7 @@ - (instancetype)initWithAuthUI:(FUIAuth *)authUI
     _signInLabel = buttonLabelText;
     _shortName = shortName;
     _buttonBackgroundColor = buttonColor;
+    _buttonTextColor = [UIColor whiteColor];
     _icon = iconImage;
     _scopes = scopes;
     _customParameters = customParameters;
@@ -185,17 +191,26 @@ + (FUIOAuth *)yahooAuthProvider {
 }
 
 + (FUIOAuth *)appleAuthProvider {
+  UIImage *iconImage = [FUIAuthUtils imageNamed:@"ic_apple"
+                            fromBundleNameOrNil:@"FirebaseOAuthUI"];
+  UIColor *buttonColor = [UIColor blackColor];
+  UIColor *buttonTextColor = [UIColor whiteColor];
+  if (UITraitCollection.currentTraitCollection.userInterfaceStyle == UIUserInterfaceStyleLight) {
+    iconImage = [iconImage imageWithTintColor:[UIColor blackColor]];
+    buttonColor = [UIColor whiteColor];
+    buttonTextColor = [UIColor blackColor];
+  }
   FUIOAuth *provider = [[FUIOAuth alloc] initWithAuthUI:[FUIAuth defaultAuthUI]
                                              providerID:@"apple.com"
                                         buttonLabelText:@"Sign in with Apple"
                                               shortName:@"Apple"
-                                            buttonColor:[UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:1.0]
-                                              iconImage:[FUIAuthUtils imageNamed:@"ic_apple"
-                                                             fromBundleNameOrNil:@"FirebaseOAuthUI"]
+                                            buttonColor:buttonColor
+                                              iconImage:iconImage
                                                  scopes:@[@"name", @"email"]
                                        customParameters:nil
                                            loginHintKey:nil];
   provider.buttonAlignment = FUIButtonAlignmentCenter;
+  provider.buttonTextColor = buttonTextColor;
   return provider;
 }
 
@@ -215,10 +230,6 @@ - (nullable NSString *)idToken {
   return nil;
 }
 
-- (UIColor *)buttonTextColor {
-  return [UIColor whiteColor];
-}
-
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wdeprecated-implementations"
 - (void)signInWithEmail:(nullable NSString *)email