[flutter_appauth] fix: change presentingViewController to topMost viewController

flutter_appauth/android/src/main/AndroidManifest.xml

@@ -5,5 +5,7 @@
     <activity android:name="net.openid.appauth.RedirectUriReceiverActivity"
       android:theme="@style/Theme.AppCompat.Translucent.NoTitleBar"
       tools:replace="android:theme" />
+    <activity android:name="AppAuthIntentLauncherActivity"
+        android:theme="@style/Theme.AppCompat.Translucent.NoTitleBar"/>
   </application>
 </manifest>

flutter_appauth/android/src/main/java/io/crossingthestreams/flutterappauth/AppAuthIntentLauncherActivity.java

@@ -0,0 +1,37 @@
+package io.crossingthestreams.flutterappauth;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.os.Bundle;
+
+public class AppAuthIntentLauncherActivity extends Activity {
+  static class IntentExtraKey {
+    static String INTENT = "intent";
+    static String REQUEST_CODE = "requestCode";
+  }
+
+  @Override
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+
+    Intent intent = getIntent().getParcelableExtra(IntentExtraKey.INTENT);
+    if (intent != null) {
+      int requestCode = getIntent().getIntExtra(IntentExtraKey.REQUEST_CODE, 0);
+      startActivityForResult(intent, requestCode);
+    } else {
+      finish();
+    }
+  }
+
+  @Override
+  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
+    super.onActivityResult(requestCode, resultCode, data);
+
+    finish();
+
+    FlutterAppauthPlugin flutterAppauthPlugin = FlutterAppauthPlugin.getInstance();
+    if (flutterAppauthPlugin != null) {
+      flutterAppauthPlugin.onActivityResult(requestCode, resultCode, data);
+    }
+  }
+}

flutter_appauth/android/src/main/java/io/crossingthestreams/flutterappauth/FlutterAppauthPlugin.java

@@ -93,6 +93,12 @@ public class FlutterAppauthPlugin
   private AuthorizationService defaultAuthorizationService;
   private AuthorizationService insecureAuthorizationService;
 
+  private static FlutterAppauthPlugin instance = null;
+
+  @Nullable static FlutterAppauthPlugin getInstance() {
+    return instance;
+  }
+
   private void onAttachedToEngine(Context context, BinaryMessenger binaryMessenger) {
     this.applicationContext = context;
     createAuthorizationServices();
@@ -104,11 +110,13 @@ private void onAttachedToEngine(Context context, BinaryMessenger binaryMessenger
   @Override
   public void onAttachedToEngine(FlutterPluginBinding binding) {
     onAttachedToEngine(binding.getApplicationContext(), binding.getBinaryMessenger());
+    instance = this;
   }
 
   @Override
   public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
     disposeAuthorizationServices();
+    instance = null;
   }
 
   @Override
@@ -466,15 +474,21 @@ private void performAuthorization(
     try {
       Intent authIntent =
           authorizationService.getAuthorizationRequestIntent(authRequestBuilder.build());
-      mainActivity.startActivityForResult(
-          authIntent, exchangeCode ? RC_AUTH_EXCHANGE_CODE : RC_AUTH);
+      startIntentLauncherActivityForResult(authIntent, exchangeCode ? RC_AUTH_EXCHANGE_CODE : RC_AUTH);
     } catch (ActivityNotFoundException ex) {
       finishWithError(NO_BROWSER_AVAILABLE_ERROR_CODE, NO_BROWSER_AVAILABLE_ERROR_FORMAT, ex);
     } catch (NullPointerException ex) {
       finishWithError(NULL_ACTIVITY_ERROR_CODE, NULL_ACTIVITY_ERROR_FORMAT, ex);
     }
   }
 
+  private void startIntentLauncherActivityForResult(Intent intent, int requestCode) {
+    Intent launcherIntent = new Intent(mainActivity, AppAuthIntentLauncherActivity.class);
+    launcherIntent.putExtra(AppAuthIntentLauncherActivity.IntentExtraKey.INTENT, intent);
+    launcherIntent.putExtra(AppAuthIntentLauncherActivity.IntentExtraKey.REQUEST_CODE, requestCode);
+    mainActivity.startActivity(launcherIntent);
+  }
+
   private void performTokenRequest(
       AuthorizationServiceConfiguration serviceConfiguration,
       TokenRequestParameters tokenRequestParameters) {
@@ -584,7 +598,7 @@ private void performEndSessionRequest(
     Intent endSessionIntent = authorizationService.getEndSessionRequestIntent(endSessionRequest);
 
     try {
-      mainActivity.startActivityForResult(endSessionIntent, RC_END_SESSION);
+      startIntentLauncherActivityForResult(endSessionIntent, RC_END_SESSION);
     } catch (NullPointerException ex) {
       finishWithError(NULL_ACTIVITY_ERROR_CODE, NULL_ACTIVITY_ERROR_FORMAT, ex);
     }

flutter_appauth/ios/flutter_appauth/Sources/flutter_appauth/AppAuthIOSAuthorization.m

@@ -32,10 +32,10 @@ @implementation AppAuthIOSAuthorization
               codeChallenge:codeChallenge
         codeChallengeMethod:OIDOAuthorizationRequestCodeChallengeMethodS256
        additionalParameters:additionalParameters];
-  UIViewController *rootViewController = [self rootViewController];
+  UIViewController *presentingViewController = [self topMostViewController];
   if (exchangeCode) {
     id<OIDExternalUserAgent> agent =
-        [self userAgentWithViewController:rootViewController
+        [self userAgentWithViewController:presentingViewController
                         externalUserAgent:externalUserAgent];
     return [OIDAuthState
         authStateByPresentingAuthorizationRequest:request
@@ -67,7 +67,7 @@ @implementation AppAuthIOSAuthorization
                                          }];
   } else {
     id<OIDExternalUserAgent> agent =
-        [self userAgentWithViewController:rootViewController
+        [self userAgentWithViewController:presentingViewController
                         externalUserAgent:externalUserAgent];
     return [OIDAuthorizationService
         presentAuthorizationRequest:request
@@ -133,9 +133,9 @@ @implementation AppAuthIOSAuthorization
                 postLogoutRedirectURL:postLogoutRedirectURL
                  additionalParameters:requestParameters.additionalParameters];
 
-  UIViewController *rootViewController = [self rootViewController];
+  UIViewController *presentingViewController = [self topMostViewController];
   id<OIDExternalUserAgent> externalUserAgent =
-      [self userAgentWithViewController:rootViewController
+      [self userAgentWithViewController:presentingViewController
                       externalUserAgent:requestParameters.externalUserAgent];
 
   return [OIDAuthorizationService
@@ -163,32 +163,56 @@ @implementation AppAuthIOSAuthorization
 }
 
 - (id<OIDExternalUserAgent>)
-    userAgentWithViewController:(UIViewController *)rootViewController
+    userAgentWithViewController:(UIViewController *)presentingViewController
               externalUserAgent:(NSNumber *)externalUserAgent {
   if ([externalUserAgent integerValue] == EphemeralASWebAuthenticationSession) {
     return [[OIDExternalUserAgentIOSNoSSO alloc]
-        initWithPresentingViewController:rootViewController];
+        initWithPresentingViewController:presentingViewController];
   }
   if ([externalUserAgent integerValue] == SafariViewController) {
     return [[OIDExternalUserAgentIOSSafariViewController alloc]
-        initWithPresentingViewController:rootViewController];
+        initWithPresentingViewController:presentingViewController];
   }
   return [[OIDExternalUserAgentIOS alloc]
-      initWithPresentingViewController:rootViewController];
+      initWithPresentingViewController:presentingViewController];
+}
+
+- (UIViewController *)topMostViewController {
+    return [self topMostViewControllerWithRootViewController:[self rootViewController]];
+}
+
+- (UIViewController *)topMostViewControllerWithRootViewController:(UIViewController *)viewController {
+    if (viewController.presentedViewController && !viewController.presentedViewController.isBeingDismissed) {
+        return [self topMostViewControllerWithRootViewController:viewController.presentedViewController];
+    }
+    if ([viewController isKindOfClass:[UITabBarController class]]) {
+        UITabBarController *tabBarController = (UITabBarController *)viewController;
+        return [self topMostViewControllerWithRootViewController:tabBarController.selectedViewController];
+    }
+    if ([viewController isKindOfClass:[UINavigationController class]]) {
+        UINavigationController *navController = (UINavigationController *)viewController;
+        return [self topMostViewControllerWithRootViewController:navController.visibleViewController];
+    }
+
+    return viewController;
 }
 
 - (UIViewController *)rootViewController {
-  if (@available(iOS 13, *)) {
-    return [[UIApplication sharedApplication].windows
-               filteredArrayUsingPredicate:[NSPredicate
-                                               predicateWithBlock:^BOOL(
-                                                   id window,
-                                                   NSDictionary *bindings) {
-                                                 return [window isKeyWindow];
-                                               }]]
-        .firstObject.rootViewController;
-  }
-  return [UIApplication sharedApplication].delegate.window.rootViewController;
+    if (@available(iOS 13.0, *)) {
+        for (UIScene *scene in [UIApplication sharedApplication].connectedScenes) {
+            if (scene.activationState == UISceneActivationStateForegroundActive && [scene isKindOfClass:[UIWindowScene class]]) {
+                UIWindowScene *windowScene = (UIWindowScene *)scene;
+                for (UIWindow *window in windowScene.windows) {
+                    if (window.isKeyWindow) {
+                        return window.rootViewController;
+                    }
+                }
+            }
+        }
+        return nil;
+    } else {
+        return [UIApplication sharedApplication].delegate.window.rootViewController;
+    }
 }
 
 @end