如何将 FlutterViewController 添加到 UIViewController

Question

我能找到的 Flutter 的 Add-to-App 的所有文档都演示了如何推送/继续/呈现新创建的 FlutterViewController。我需要将颤动视图添加到选项卡栏中的选项卡。我尝试将班级的超类更改为UIViewController有效FlutterViewController，但没有使用应用程序委托中创建的颤动引擎。此解决方案导致在启动屏幕中显示颤动视图之前，这是不希望的。

如何向 中添加颤动视图UIViewController？或者如何将引擎分配给FlutterViewController类内的引擎？

Answer 1

我找到了一个将颤动视图添加到视图控制器的解决方案。

// create an extension for all UIViewControllers
extension UIViewController {
     /**
         Add a flutter sub view to the UIViewController
         sets constraints to edge to edge, covering all components on the screen
     */
    func addFlutterView(with engine: FlutterEngine) {
        // create the flutter view controller
        let flutterViewController = FlutterViewController(engine: engine, nibName: nil, bundle: nil)
        
        addChild(flutterViewController)
        
        guard let flutterView = flutterViewController.view else { return }

        // allows constraint manipulation
        flutterView.translatesAutoresizingMaskIntoConstraints = false

        view.addSubview(flutterView)
        
        // set the constraints (edge-to-edge) to the flutter view
        let constraints = [
            flutterView.topAnchor.constraint(equalTo: view.topAnchor),
            flutterView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            flutterView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            flutterView.trailingAnchor.constraint(equalTo: view.trailingAnchor)
        ]

        // apply (activate) the constraints
        NSLayoutConstraint.activate(constraints)

        flutterViewController.didMove(toParent: self)
        
        // updates the view with configured layout
        flutterView.layoutIfNeeded()
    }
}

对于任何 UIViewController，您现在都可以添加一个 flutter 子视图。

override func viewDidLoad() {
    super.viewDidLoad()
    
    // get the flutter engine for the view
    let flutterEngine = (UIApplication.shared.delegate as! AppDelegate).flutterEngine
    
    // add flutter view
    addFlutterView(with: flutterEngine)

    // Do any additional setup after loading the view.
}