[image_picker] Update for UIScene compatibility (#10677)

Replaces the code that used the key window's root view controller with a call to the new registrar viewController method to get the actual Flutter content's view controller.

Introduces the same protocol abstraction now used in a number of our plugins, so that a stub can be injected without having to mock (which would be a barrier to Swift migration) or fake (which is fragile since it would have to be complete, and methods can be added over time) the entire Flutter plugin registrar.

Fixes flutter/flutter#174418

## Pre-Review Checklist

[^1]: Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling.

Author: stuartmorgan-g

packages/image_picker/image_picker_ios/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.8.13+4
+
+* Improves compatibility with `UIScene`.
+* Updates minimum supported SDK version to Flutter 3.38/Dart 3.10.
+
 ## 0.8.13+3
 
 * Fixes a performance regression on iOS where picking videos could cause a long delay due to transcoding. The picker is now configured to request the original asset to avoid conversion.

packages/image_picker/image_picker_ios/example/ios/RunnerTests/ImagePickerPluginTests.m

@@ -3,8 +3,8 @@ description: Demonstrates how to use the image_picker plugin.
 publish_to: none
 
 environment:
-  sdk: ^3.9.0
-  flutter: ">=3.35.0"
+  sdk: ^3.10.0
+  flutter: ">=3.38.0"
 
 dependencies:
   flutter:

packages/image_picker/image_picker_ios/example/pubspec.yaml

@@ -0,0 +1,26 @@
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "./include/image_picker_ios/FIPViewProvider.h"
+
+@import UIKit;
+
+@interface FIPDefaultViewProvider ()
+/// The backing registrar.
+@property(nonatomic) NSObject<FlutterPluginRegistrar> *registrar;
+@end
+
+@implementation FIPDefaultViewProvider
+- (instancetype)initWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
+  self = [super init];
+  if (self) {
+    _registrar = registrar;
+  }
+  return self;
+}
+
+- (UIViewController *)viewController {
+  return self.registrar.viewController;
+}
+@end

packages/image_picker/image_picker_ios/ios/image_picker_ios/Sources/image_picker_ios/FIPViewProvider.m

@@ -35,20 +35,32 @@ @interface FLTImagePickerPlugin ()
 /// controller would normally be created. Each call to
 /// createImagePickerController will remove the current first element from
 /// the array.
-@property(strong, nonatomic)
+@property(nonatomic, nullable)
     NSMutableArray<UIImagePickerController *> *imagePickerControllerOverrides;
 
+/// The view provider to use for displaying native view controllers.
+@property(nonatomic, nonnull) NSObject<FIPViewProvider> *viewProvider;
+
 @end
 
 typedef NS_ENUM(NSInteger, ImagePickerClassType) { UIImagePickerClassType, PHPickerClassType };
 
 @implementation FLTImagePickerPlugin
 
 + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
-  FLTImagePickerPlugin *instance = [[FLTImagePickerPlugin alloc] init];
+  FLTImagePickerPlugin *instance = [[FLTImagePickerPlugin alloc]
+      initWithViewProvider:[[FIPDefaultViewProvider alloc] initWithRegistrar:registrar]];
   SetUpFLTImagePickerApi(registrar.messenger, instance);
 }
 
+- (instancetype)initWithViewProvider:(NSObject<FIPViewProvider> *)viewProvider {
+  self = [super init];
+  if (self) {
+    _viewProvider = viewProvider;
+  }
+  return self;
+}
+
 - (UIImagePickerController *)createImagePickerController {
   if ([self.imagePickerControllerOverrides count] > 0) {
     UIImagePickerController *controller = [self.imagePickerControllerOverrides firstObject];
@@ -64,24 +76,6 @@ - (void)setImagePickerControllerOverrides:
   _imagePickerControllerOverrides = [imagePickerControllers mutableCopy];
 }
 
-- (UIViewController *)viewControllerWithWindow:(UIWindow *)window {
-  UIWindow *windowToUse = window;
-  if (windowToUse == nil) {
-    for (UIWindow *window in [UIApplication sharedApplication].windows) {
-      if (window.isKeyWindow) {
-        windowToUse = window;
-        break;
-      }
-    }
-  }
-
-  UIViewController *topController = windowToUse.rootViewController;
-  while (topController.presentedViewController) {
-    topController = topController.presentedViewController;
-  }
-  return topController;
-}
-
 /// Returns the UIImagePickerControllerCameraDevice to use given [source].
 ///
 /// @param source The source specification from Dart.
@@ -323,9 +317,9 @@ - (void)showCamera:(UIImagePickerControllerCameraDevice)device
       [UIImagePickerController isCameraDeviceAvailable:device]) {
     imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
     imagePickerController.cameraDevice = device;
-    [[self viewControllerWithWindow:nil] presentViewController:imagePickerController
-                                                      animated:YES
-                                                    completion:nil];
+    [self.viewProvider.viewController presentViewController:imagePickerController
+                                                   animated:YES
+                                                 completion:nil];
   } else {
     UIAlertController *cameraErrorAlert = [UIAlertController
         alertControllerWithTitle:NSLocalizedString(@"Error", @"Alert title when camera unavailable")
@@ -338,9 +332,9 @@ - (void)showCamera:(UIImagePickerControllerCameraDevice)device
                                            style:UIAlertActionStyleDefault
                                          handler:^(UIAlertAction *action){
                                          }]];
-    [[self viewControllerWithWindow:nil] presentViewController:cameraErrorAlert
-                                                      animated:YES
-                                                    completion:nil];
+    [self.viewProvider.viewController presentViewController:cameraErrorAlert
+                                                   animated:YES
+                                                 completion:nil];
     [self sendCallResultWithSavedPathList:nil];
   }
 }
@@ -438,16 +432,16 @@ - (void)errorNoPhotoAccess:(PHAuthorizationStatus)status {
 
 - (void)showPhotoLibraryWithPHPicker:(PHPickerViewController *)pickerViewController
     API_AVAILABLE(ios(14)) {
-  [[self viewControllerWithWindow:nil] presentViewController:pickerViewController
-                                                    animated:YES
-                                                  completion:nil];
+  [self.viewProvider.viewController presentViewController:pickerViewController
+                                                 animated:YES
+                                               completion:nil];
 }
 
 - (void)showPhotoLibraryWithImagePicker:(UIImagePickerController *)imagePickerController {
   imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
-  [[self viewControllerWithWindow:nil] presentViewController:imagePickerController
-                                                    animated:YES
-                                                  completion:nil];
+  [self.viewProvider.viewController presentViewController:imagePickerController
+                                                 animated:YES
+                                               completion:nil];
 }
 
 - (NSNumber *)getDesiredImageQuality:(NSNumber *)imageQuality {

packages/image_picker/image_picker_ios/ios/image_picker_ios/Sources/image_picker_ios/FLTImagePickerPlugin.m

@@ -5,6 +5,7 @@ framework module image_picker_ios {
   module * { export * }
 
   explicit module Test {
+    header "FIPViewProvider.h"
     header "FLTImagePickerPlugin_Test.h"
     header "FLTImagePickerImageUtil.h"
     header "FLTImagePickerMetaDataUtil.h"

packages/image_picker/image_picker_ios/ios/image_picker_ios/Sources/image_picker_ios/include/ImagePickerPlugin.modulemap

@@ -0,0 +1,25 @@
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+@import Flutter;
+@import UIKit;
+
+NS_ASSUME_NONNULL_BEGIN
+
+/// Protocol for obtaining the view controller containing the Flutter content.
+@protocol FIPViewProvider <NSObject>
+@required
+/// The view controller containing the Flutter content.
+@property(nonatomic, readonly, nullable) UIViewController *viewController;
+@end
+
+/// A default implementation of the FIPViewProvider protocol.
+@interface FIPDefaultViewProvider : NSObject <FIPViewProvider>
+/// Returns a provider backed by the given registrar.
+- (instancetype)initWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar
+    NS_DESIGNATED_INITIALIZER;
+- (instancetype)init NS_UNAVAILABLE;
+@end
+
+NS_ASSUME_NONNULL_END

packages/image_picker/image_picker_ios/ios/image_picker_ios/Sources/image_picker_ios/include/image_picker_ios/FIPViewProvider.h

@@ -8,6 +8,9 @@
 NS_ASSUME_NONNULL_BEGIN
 
 @interface FLTImagePickerPlugin : NSObject <FlutterPlugin>
+/// FLTImagePickerPlugin has no public initializers, as it should not be
+/// created directly by plugin clients.
+- (instancetype)init NS_UNAVAILABLE;
 @end
 
 NS_ASSUME_NONNULL_END

packages/image_picker/image_picker_ios/ios/image_picker_ios/Sources/image_picker_ios/include/image_picker_ios/FLTImagePickerPlugin.h

@@ -4,8 +4,8 @@
 
 // This header is available in the Test module. Import via "@import image_picker_ios_ios.Test;"
 
-#import <image_picker_ios/FLTImagePickerPlugin.h>
-
+#import "FIPViewProvider.h"
+#import "FLTImagePickerPlugin.h"
 #import "messages.g.h"
 
 NS_ASSUME_NONNULL_BEGIN
@@ -62,7 +62,7 @@ typedef void (^FlutterResultAdapter)(NSArray<NSString *> *_Nullable, FlutterErro
 /// The context of the Flutter method call that is currently being handled, if any.
 @property(strong, nonatomic, nullable) FLTImagePickerMethodCallContext *callContext;
 
-- (UIViewController *)viewControllerWithWindow:(nullable UIWindow *)window;
+- (instancetype)initWithViewProvider:(NSObject<FIPViewProvider> *)viewProvider;
 
 /// Validates the provided paths list, then sends it via `callContext.result` as the result of the
 /// original platform channel method call, clearing the in-progress call state.

packages/image_picker/image_picker_ios/ios/image_picker_ios/Sources/image_picker_ios/include/image_picker_ios/FLTImagePickerPlugin_Test.h

@@ -2,11 +2,11 @@ name: image_picker_ios
 description: iOS implementation of the image_picker plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/image_picker/image_picker_ios
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+image_picker%22
-version: 0.8.13+3
+version: 0.8.13+4
 
 environment:
-  sdk: ^3.9.0
-  flutter: ">=3.35.0"
+  sdk: ^3.10.0
+  flutter: ">=3.38.0"
 
 flutter:
   plugin: