com.facebook.litho.annotations

Annotation Type OnCreateInitialState

@Retention(value=RUNTIME)
public @interface OnCreateInitialState

This annotation is used in a LayoutSpec; the framework calls the method annotated with OnCreateInitialState before resolving its layout, i.e. before calling OnCreateLayout. This lifecycle method should be used to set the initial values of the state of the component. The annotate method can receive StateValue containers for arguments annotated with State.

The framework can call OnCreateInitialState from any thread. The method is invoked only once during the lifecycle of the Component inside a ComponentTree - when it is first added to the layout hierarchy. Any updates, such as state updates or prop changes, will not invoke this method again if its global key did not change. Removing a component and adding it back to the hierarchy will invoke this method again.

Required:

1. ComponentContext

Optional annotated arguments:

• Prop
• TreeProp
• InjectProp
• StateValue

 @LayoutSpec
 public class CounterSpec {

   @OnCreateInitialState
   static void onCreateInitialState(
       ComponentContext c,
       StateValue<Integer> count) {
     count.set(0);
   }

   @OnCreateLayout
   static Component onCreateLayout(
     ComponentContext c,
     @State int count) {

     return Row.create(c)
       .child(
         Text.create(c)
           .text(String.valueOf(count))
       )
       .build();
   }
 }