io.flutter.embedding.engine

Class FlutterEngineGroup

java.lang.Object

io.flutter.embedding.engine.FlutterEngineGroup

public class FlutterEngineGroup
extends Object

This class is experimental. Please do not ship production code using it.

Represents a collection of FlutterEngines who share resources to allow them to be created faster and with less memory than calling the FlutterEngine's constructor multiple times.

When creating or recreating the first FlutterEngine in the FlutterEngineGroup, the behavior is the same as creating a FlutterEngine via its constructor. When subsequent FlutterEngines are created, resources from an existing living FlutterEngine is re-used.

The shared resources are kept until the last surviving FlutterEngine is destroyed.

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

Constructor Summary

Constructors

Constructor and Description
FlutterEngineGroup(Context context) Create a FlutterEngineGroup whose child engines will share resources.
FlutterEngineGroup(Context context, String[] dartVmArgs) Create a FlutterEngineGroup whose child engines will share resources.

Method Summary

Modifier and Type	Method and Description
FlutterEngine	createAndRunDefaultEngine(Context context) Creates a FlutterEngine in this group and run its DartExecutor with a default entrypoint of the "main" function in the "lib/main.dart" file.
FlutterEngine	createAndRunEngine(Context context, DartExecutor.DartEntrypoint dartEntrypoint) Creates a FlutterEngine in this group and run its DartExecutor with the specified DartExecutor.DartEntrypoint.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FlutterEngineGroup

public FlutterEngineGroup(@NonNull
                          Context context)

Create a FlutterEngineGroup whose child engines will share resources.

FlutterEngineGroup

public FlutterEngineGroup(@NonNull
                          Context context,
                          @Nullable
                          String[] dartVmArgs)

Create a FlutterEngineGroup whose child engines will share resources. Use dartVmArgs to pass flags to the Dart VM during initialization.

Method Detail

createAndRunDefaultEngine

public FlutterEngine createAndRunDefaultEngine(@NonNull
                                               Context context)

Creates a FlutterEngine in this group and run its DartExecutor with a default entrypoint of the "main" function in the "lib/main.dart" file.

If no prior FlutterEngine were created in this group, the initialization cost will be slightly higher than subsequent engines. The very first FlutterEngine created per program, regardless of FlutterEngineGroup, also incurs the Dart VM creation time.

Subsequent engine creations will share resources with existing engines. However, if all existing engines were FlutterEngine.destroy()ed, the next engine created will recreate its dependencies.

createAndRunEngine

public FlutterEngine createAndRunEngine(@NonNull
                                        Context context,
                                        @Nullable
                                        DartExecutor.DartEntrypoint dartEntrypoint)

Creates a FlutterEngine in this group and run its DartExecutor with the specified DartExecutor.DartEntrypoint.

If no prior FlutterEngine were created in this group, the initialization cost will be slightly higher than subsequent engines. The very first FlutterEngine created per program, regardless of FlutterEngineGroup, also incurs the Dart VM creation time.

Subsequent engine creations will share resources with existing engines. However, if all existing engines were FlutterEngine.destroy()ed, the next engine created will recreate its dependencies.