iOS アプリに Flutter 画面を追加する

import UIKit
import Flutter
// The following library connects plugins with iOS platform code to this app.
import FlutterPluginRegistrant

@UIApplicationMain
class AppDelegate: FlutterAppDelegate { // More on the FlutterAppDelegate.
  lazy var flutterEngine = FlutterEngine(name: "my flutter engine")

  override func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    // Runs the default Dart entrypoint with a default Flutter route.
    flutterEngine.run();
    // Connects plugins with iOS platform code to this app.
    GeneratedPluginRegistrant.register(with: self.flutterEngine);
    return super.application(application, didFinishLaunchingWithOptions: launchOptions);
  }
}

@import UIKit;
@import Flutter;

@interface AppDelegate : FlutterAppDelegate // More on the FlutterAppDelegate below.
@property (nonatomic,strong) FlutterEngine *flutterEngine;
@end

// The following library connects plugins with iOS platform code to this app.
#import <FlutterPluginRegistrant/GeneratedPluginRegistrant.h>

#import "AppDelegate.h"

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application
    didFinishLaunchingWithOptions:(NSDictionary<UIApplicationLaunchOptionsKey, id> *)launchOptions {
  self.flutterEngine = [[FlutterEngine alloc] initWithName:@"my flutter engine"];
  // Runs the default Dart entrypoint with a default Flutter route.
  [self.flutterEngine run];
  // Connects plugins with iOS platform code to this app.
  [GeneratedPluginRegistrant registerWithRegistry:self.flutterEngine];
  return [super application:application didFinishLaunchingWithOptions:launchOptions];
}

@end

import UIKit
import Flutter

class ViewController: UIViewController {
  override func viewDidLoad() {
    super.viewDidLoad()

    // Make a button to call the showFlutter function when pressed.
    let button = UIButton(type:UIButton.ButtonType.custom)
    button.addTarget(self, action: #selector(showFlutter), for: .touchUpInside)
    button.setTitle("Show Flutter!", for: UIControl.State.normal)
    button.frame = CGRect(x: 80.0, y: 210.0, width: 160.0, height: 40.0)
    button.backgroundColor = UIColor.blue
    self.view.addSubview(button)
  }

  @objc func showFlutter() {
    let flutterEngine = (UIApplication.shared.delegate as! AppDelegate).flutterEngine
    let flutterViewController =
        FlutterViewController(engine: flutterEngine, nibName: nil, bundle: nil)
    present(flutterViewController, animated: true, completion: nil)
  }
}

@import Flutter;
#import "AppDelegate.h"
#import "ViewController.h"

@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];

    // Make a button to call the showFlutter function when pressed.
    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
    [button addTarget:self
               action:@selector(showFlutter)
     forControlEvents:UIControlEventTouchUpInside];
    [button setTitle:@"Show Flutter!" forState:UIControlStateNormal];
    button.backgroundColor = UIColor.blueColor;
    button.frame = CGRectMake(80.0, 210.0, 160.0, 40.0);
    [self.view addSubview:button];
}

- (void)showFlutter {
    FlutterEngine *flutterEngine =
        ((AppDelegate *)UIApplication.sharedApplication.delegate).flutterEngine;
    FlutterViewController *flutterViewController =
        [[FlutterViewController alloc] initWithEngine:flutterEngine nibName:nil bundle:nil];
    [self presentViewController:flutterViewController animated:YES completion:nil];
}
@end

// Existing code omitted.
func showFlutter() {
  let flutterViewController = FlutterViewController(project: nil, nibName: nil, bundle: nil)
  present(flutterViewController, animated: true, completion: nil)
}

// Existing code omitted.
- (void)showFlutter {
  FlutterViewController *flutterViewController =
      [[FlutterViewController alloc] initWithProject:nil nibName:nil bundle:nil];
  [self presentViewController:flutterViewController animated:YES completion:nil];
}
@end

@import Flutter;
@import UIKit;
@import FlutterPluginRegistrant;

@interface AppDelegate : UIResponder <UIApplicationDelegate, FlutterAppLifeCycleProvider>
@property (strong, nonatomic) UIWindow *window;
@property (nonatomic,strong) FlutterEngine *flutterEngine;
@end

@interface AppDelegate ()
@property (nonatomic, strong) FlutterPluginAppLifeCycleDelegate* lifeCycleDelegate;
@end

@implementation AppDelegate

- (instancetype)init {
    if (self = [super init]) {
        _lifeCycleDelegate = [[FlutterPluginAppLifeCycleDelegate alloc] init];
    }
    return self;
}

- (BOOL)application:(UIApplication*)application
didFinishLaunchingWithOptions:(NSDictionary<UIApplicationLaunchOptionsKey, id>*))launchOptions {
    self.flutterEngine = [[FlutterEngine alloc] initWithName:@"io.flutter" project:nil];
    [self.flutterEngine runWithEntrypoint:nil];
    [GeneratedPluginRegistrant registerWithRegistry:self.flutterEngine];
    return [_lifeCycleDelegate application:application didFinishLaunchingWithOptions:launchOptions];
}

// Returns the key window's rootViewController, if it's a FlutterViewController.
// Otherwise, returns nil.
- (FlutterViewController*)rootFlutterViewController {
    UIViewController* viewController = [UIApplication sharedApplication].keyWindow.rootViewController;
    if ([viewController isKindOfClass:[FlutterViewController class]]) {
        return (FlutterViewController*)viewController;
    }
    return nil;
}

- (void)application:(UIApplication*)application
didRegisterUserNotificationSettings:(UIUserNotificationSettings*)notificationSettings {
    [_lifeCycleDelegate application:application
didRegisterUserNotificationSettings:notificationSettings];
}

- (void)application:(UIApplication*)application
didRegisterForRemoteNotificationsWithDeviceToken:(NSData*)deviceToken {
    [_lifeCycleDelegate application:application
didRegisterForRemoteNotificationsWithDeviceToken:deviceToken];
}

- (void)application:(UIApplication*)application
didReceiveRemoteNotification:(NSDictionary*)userInfo
fetchCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler {
    [_lifeCycleDelegate application:application
       didReceiveRemoteNotification:userInfo
             fetchCompletionHandler:completionHandler];
}

- (BOOL)application:(UIApplication*)application
            openURL:(NSURL*)url
            options:(NSDictionary<UIApplicationOpenURLOptionsKey, id>*)options {
    return [_lifeCycleDelegate application:application openURL:url options:options];
}

- (BOOL)application:(UIApplication*)application handleOpenURL:(NSURL*)url {
    return [_lifeCycleDelegate application:application handleOpenURL:url];
}

- (BOOL)application:(UIApplication*)application
            openURL:(NSURL*)url
  sourceApplication:(NSString*)sourceApplication
         annotation:(id)annotation {
    return [_lifeCycleDelegate application:application
                                   openURL:url
                         sourceApplication:sourceApplication
                                annotation:annotation];
}

- (void)application:(UIApplication*)application
performActionForShortcutItem:(UIApplicationShortcutItem*)shortcutItem
  completionHandler:(void (^)(BOOL succeeded))completionHandler {
    [_lifeCycleDelegate application:application
       performActionForShortcutItem:shortcutItem
                  completionHandler:completionHandler];
}

- (void)application:(UIApplication*)application
handleEventsForBackgroundURLSession:(nonnull NSString*)identifier
  completionHandler:(nonnull void (^)(void))completionHandler {
    [_lifeCycleDelegate application:application
handleEventsForBackgroundURLSession:identifier
                  completionHandler:completionHandler];
}

- (void)application:(UIApplication*)application
performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler {
    [_lifeCycleDelegate application:application performFetchWithCompletionHandler:completionHandler];
}

- (void)addApplicationLifeCycleDelegate:(NSObject<FlutterPlugin>*)delegate {
    [_lifeCycleDelegate addDelegate:delegate];
}
@end