FlutterEngineGroup Class Reference

#include <FlutterEngineGroup.h>

Inheritance diagram for FlutterEngineGroup:

Instance Methods
(instancetype)	- NS_UNAVAILABLE
(instancetype)	- initWithName:project:
(FlutterEngine *)	- makeEngineWithEntrypoint:libraryURI:
(FlutterEngine *)	- makeEngineWithEntrypoint:libraryURI:initialRoute:
(FlutterEngine *)	- makeEngineWithOptions:

Detailed Description

Represents a collection of FlutterEngines who share resources which allows them to be created with less time const and occupy less memory than just creating multiple FlutterEngines.

Deleting a FlutterEngineGroup doesn't invalidate existing FlutterEngines, but it eliminates the possibility to create more FlutterEngines in that group.

Warning

This class is a work-in-progress and may change.

See also

https://github.com/flutter/flutter/issues/72009

Definition at line 56 of file FlutterEngineGroup.h.

Method Documentation

initWithName:project:

- (instancetype) initWithName:		(NSString*)	name
project:		(nullable FlutterDartProject*)	NS_DESIGNATED_INITIALIZER

Initialize a new FlutterEngineGroup.

Parameters

name	The name that will present in the threads shared across the engines in this group.
project	The FlutterDartProject that all FlutterEngines in this group will be executing.

Definition at line 17 of file FlutterEngineGroup.mm.

                            :(NSString*)name project:(nullable FlutterDartProject*)project {
  self = [super init];
  if (self) {
    _name = [name copy];
    _engines = [NSPointerArray weakObjectsPointerArray];
    _project = project;
  }
  return self;
}

makeEngineWithEntrypoint:libraryURI:

- (FlutterEngine *) makeEngineWithEntrypoint:		(nullable NSString*)	entrypoint
libraryURI:		(nullable NSString*)	libraryURI

Creates a running FlutterEngine that shares components with this group.

Parameters

entrypoint	The name of a top-level function from a Dart library. If this is FlutterDefaultDartEntrypoint (or nil); this will default to main(). If it is not the app's main() function, that function must be decorated with @pragma(vm:entry-point) to ensure the method is not tree-shaken by the Dart compiler.
libraryURI	The URI of the Dart library which contains the entrypoint method. IF nil, this will default to the same library as the main() function in the Dart program.

See also

FlutterEngineGroup

Definition at line 17 of file FlutterEngineGroup.mm.

                                          :(nullable NSString*)entrypoint
                                libraryURI:(nullable NSString*)libraryURI {
  return [self makeEngineWithEntrypoint:entrypoint libraryURI:libraryURI initialRoute:nil];
}

makeEngineWithEntrypoint:libraryURI:initialRoute:

- (FlutterEngine *) makeEngineWithEntrypoint:		(nullable NSString*)	entrypoint
libraryURI:		(nullable NSString*)	libraryURI
initialRoute:		(nullable NSString*)	initialRoute

Creates a running FlutterEngine that shares components with this group.

Parameters

entrypoint	The name of a top-level function from a Dart library. If this is FlutterDefaultDartEntrypoint (or nil); this will default to main(). If it is not the app's main() function, that function must be decorated with @pragma(vm:entry-point) to ensure the method is not tree-shaken by the Dart compiler.
libraryURI	The URI of the Dart library which contains the entrypoint method. IF nil, this will default to the same library as the main() function in the Dart program.
initialRoute	The name of the initial Flutter Navigator Route to load. If this is FlutterDefaultInitialRoute (or nil), it will default to the "/" route.

See also

FlutterEngineGroup

Definition at line 17 of file FlutterEngineGroup.mm.

                                          :(nullable NSString*)entrypoint
                                libraryURI:(nullable NSString*)libraryURI
                              initialRoute:(nullable NSString*)initialRoute {
  FlutterEngineGroupOptions* options = [[FlutterEngineGroupOptions alloc] init];
  options.entrypoint = entrypoint;
  options.libraryURI = libraryURI;
  options.initialRoute = initialRoute;
  return [self makeEngineWithOptions:options];
}

makeEngineWithOptions:

- (FlutterEngine *) makeEngineWithOptions:

(nullable FlutterEngineGroupOptions*)

options

Creates a running FlutterEngine that shares components with this group.

Parameters

options

Options that control how a FlutterEngine should be created.

See also

FlutterEngineGroupOptions

Definition at line 17 of file FlutterEngineGroup.mm.

                                       :(nullable FlutterEngineGroupOptions*)options {
  NSString* entrypoint = options.entrypoint;
  NSString* libraryURI = options.libraryURI;
  NSString* initialRoute = options.initialRoute;
  NSArray<NSString*>* entrypointArgs = options.entrypointArgs;
 
  FlutterEngine* engine;
  // NSPointerArray is clever and assumes that unless a mutation operation has occurred on it that
  // has set one of its values to nil, nothing could have changed and it can skip compaction.
  // That's reasonable behaviour on a regular NSPointerArray but not for a weakObjectPointerArray.
  // As a workaround, we mutate it first. See: http://www.openradar.me/15396578
  [self.engines addPointer:nil];
  [self.engines compact];
  if (self.engines.count <= 0) {
    engine = [self makeEngine];
    [engine runWithEntrypoint:entrypoint
                   libraryURI:libraryURI
                 initialRoute:initialRoute
               entrypointArgs:entrypointArgs];
  } else {
    FlutterEngine* spawner = (__bridge FlutterEngine*)[self.engines pointerAtIndex:0];
    engine = [spawner spawnWithEntrypoint:entrypoint
                               libraryURI:libraryURI
                             initialRoute:initialRoute
                           entrypointArgs:entrypointArgs];
  }
  [self.engines addPointer:(__bridge void*)engine];
 
  return engine;
}

NS_UNAVAILABLE

- (instancetype) NS_UNAVAILABLE

---

The documentation for this class was generated from the following files:

• shell/platform/darwin/ios/framework/Headers/FlutterEngineGroup.h
• shell/platform/darwin/ios/framework/Source/FlutterEngineGroup.mm