FlutterViewController

@interface FlutterViewController
    : UIViewController <FlutterTextureRegistry, FlutterPluginRegistry>

A UIViewController implementation for Flutter views.

Dart execution, channel communication, texture registration, and plugin registration are all handled by FlutterEngine. Calls on this class to those members all proxy through to the FlutterEngine attached FlutterViewController.

A FlutterViewController can be initialized either with an already-running FlutterEngine via the initWithEngine: initializer, or it can be initialized with a FlutterDartProject that will be used to implicitly spin up a new FlutterEngine. Creating a FlutterEngine before showing a FlutterViewController can be used to pre-initialize the Dart VM and to prepare the isolate in order to reduce the latency to the first rendered frame. See https://flutter.cn/docs/development/add-to-app/performance for more details on loading latency.

Holding a FlutterEngine independently of FlutterViewControllers can also be used to not to lose Dart-related state and asynchronous tasks when navigating back and forth between a FlutterViewController and other UIViewControllers.

  • Initializes this FlutterViewController with the specified FlutterEngine.

    The initialized viewcontroller will attach itself to the engine as part of this process.

    Declaration

    Objective-C

    - (nonnull instancetype)initWithEngine:(nonnull FlutterEngine *)engine
                               nibName:(nullable NSString *)nibName
                                bundle:(nullable NSBundle *)nibBundle;

    Parameters

    engine

    The FlutterEngine instance to attach to. Cannot be nil.
    nibName

    The NIB name to initialize this UIViewController with.
    nibBundle

    The NIB bundle.

  • Initializes a new FlutterViewController and FlutterEngine with the specified FlutterDartProject.

    This will implicitly create a new FlutterEngine which is retrievable via the engine property after initialization.

    Declaration

    Objective-C

    - (nonnull instancetype)initWithProject:(nullable FlutterDartProject *)project
                                nibName:(nullable NSString *)nibName
                                 bundle:(nullable NSBundle *)nibBundle;

    Parameters

    project

    The FlutterDartProject to initialize the FlutterEngine with.
    nibName

    The NIB name to initialize this UIViewController with.
    nibBundle

    The NIB bundle.

  • Initializes a new FlutterViewController and FlutterEngine with the specified FlutterDartProject and initialRoute.

    This will implicitly create a new FlutterEngine which is retrievable via the engine property after initialization.

    Declaration

    Objective-C

    - (nonnull instancetype)initWithProject:(nullable FlutterDartProject *)project
                           initialRoute:(nullable NSString *)initialRoute
                                nibName:(nullable NSString *)nibName
                                 bundle:(nullable NSBundle *)nibBundle;

    Parameters

    project

    The FlutterDartProject to initialize the FlutterEngine with.
    initialRoute

    The initial Navigator route to load.
    nibName

    The NIB name to initialize this UIViewController with.
    nibBundle

    The NIB bundle.

  • Initializer that is called from loading a FlutterViewController from a XIB.

    See also: https://developer.apple.com/documentation/foundation/nscoding/1416145-initwithcoder?language=objc

    Declaration

    Objective-C

    - (nonnull instancetype)initWithCoder:(nonnull NSCoder *)aDecoder;

  • Registers a callback that will be invoked when the Flutter view has been rendered. The callback will be fired only once.

    Replaces an existing callback. Use a nil callback to unregister the existing one.

    Declaration

    Objective-C

    - (void)setFlutterViewDidRenderCallback:(nonnull void (^)(void))callback;

  • Returns the file name for the given asset. The returned file name can be used to access the asset in the application’s main bundle.

    Declaration

    Objective-C

    - (nonnull NSString *)lookupKeyForAsset:(nonnull NSString *)asset;

    Parameters

    asset

    The name of the asset. The name can be hierarchical.

    Return Value

    The file name to be used for lookup in the main bundle.

  • Returns the file name for the given asset which originates from the specified package. The returned file name can be used to access the asset in the application’s main bundle.

    Declaration

    Objective-C

    - (nonnull NSString *)lookupKeyForAsset:(nonnull NSString *)asset
                            fromPackage:(nonnull NSString *)package;

    Parameters

    asset

    The name of the asset. The name can be hierarchical.
    package

    The name of the package from which the asset originates.

    Return Value

    The file name to be used for lookup in the main bundle.

  • Deprecated

    Use FlutterViewController initializer to specify initial route

    Deprecated API to set initial route.

    Attempts to set the first route that the Flutter app shows if the Flutter runtime hasn’t yet started. The default is /.

    This method must be called immediately after initWithProject and has no effect when using initWithEngine if the FlutterEngine has already been run.

    Setting this after the Flutter started running has no effect. See pushRoute and popRoute to change the route after Flutter started running.

    This is deprecated because it needs to be called at the time of initialization and thus should just be in the initWithProject initializer. If using initWithEngine, the initial route should be set on the engine’s initializer.

    Declaration

    Objective-C

    - (void)setInitialRoute:(nonnull NSString *)route;

    Parameters

    route

    The name of the first route to show.

  • Instructs the Flutter Navigator (if any) to go back.

    Declaration

    Objective-C

    - (void)popRoute;

  • Instructs the Flutter Navigator (if any) to push a route on to the navigation stack.

    Declaration

    Objective-C

    - (void)pushRoute:(nonnull NSString *)route;

    Parameters

    route

    The name of the route to push to the navigation stack.

  • The FlutterPluginRegistry used by this FlutterViewController.

    Declaration

    Objective-C

    - (nonnull id<FlutterPluginRegistry>)pluginRegistry;

  • True if at least one frame has rendered and the ViewController has appeared.

    This property is reset to false when the ViewController disappears. It is guaranteed to only alternate between true and false for observers.

    Declaration

    Objective-C

    @property (nonatomic, readonly, getter=isDisplayingFlutterUI)
    BOOL displayingFlutterUI;

  • Specifies the view to use as a splash screen. Flutter’s rendering is asynchronous, so the first frame rendered by the Flutter application might not immediately appear when theFlutter view is initially placed in the view hierarchy. The splash screen view will be used as a replacement until the first frame is rendered.

    The view used should be appropriate for multiple sizes; an autoresizing mask to have a flexible width and height will be applied automatically.

    Declaration

    Objective-C

    @property (nonatomic, strong, readwrite) UIView *_Nonnull splashScreenView;

  • Attempts to set the splashScreenView property from the UILaunchStoryboardName from the main bundle’s Info.plist file. This method will not change the value of splashScreenView if it cannot find a default one from a storyboard or nib.

    Declaration

    Objective-C

    - (BOOL)loadDefaultSplashScreenView;

    Return Value

    YES if successful, NO otherwise.

  • Controls whether the created view will be opaque or not.

    Default is YES. Note that setting this to NO may negatively impact performance when using hardware acceleration, and toggling this will trigger a re-layout of the view.

    Declaration

    Objective-C

    @property (nonatomic, assign, unsafe_unretained, readwrite, getter=isViewOpaque)
    BOOL viewOpaque;

  • The FlutterEngine instance for this view controller. This could be the engine this FlutterViewController is initialized with or a new FlutterEngine implicitly created if no engine was supplied during initialization.

    Declaration

    Objective-C

    @property (nonatomic, weak, readonly) FlutterEngine *_Nullable engine;

  • The FlutterBinaryMessenger associated with this FlutterViewController (used for communicating with channels).

    This is just a convenient way to get the |FlutterEngine|‘s binary messenger.

    Declaration

    Objective-C

    @property (nonatomic, readonly)
    NSObject<FlutterBinaryMessenger> *_Nonnull binaryMessenger;

  • If the FlutterViewController creates a FlutterEngine, this property determines if that FlutterEngine has allowHeadlessExecution set.

    The intention is that this is used with the XIB. Otherwise, a FlutterEngine can just be sent to the init methods.

    See also: -[FlutterEngine initWithName:project:allowHeadlessExecution:]

    Declaration

    Objective-C

    @property (nonatomic, readonly) BOOL engineAllowHeadlessExecution;