Event Sync

FullScreenComponentSpec-1.java

@LayoutSpec(events = { LikeChangeEvent.class })
public class FullScreenComponentSpec {

  ... other stuff

  @OnEvent(ClickEvent.class)
  static void onLikeButtonClicked(ComponentContext c, @State boolean isLiked, @Prop GifItem gif, @Prop Component gifComponent) {
    FullScreenComponent.updateLikeButtonAsync(c, !isLiked);

    FullScreenComponent.dispatchLikeChangeEvent(FullScreenComponent.getLikeChangeEventHandler(c), !isLiked, gif.getId());
    
    // Create EventHandler from gifComponent scope.
    EventHandler<FavChangeEvent> handler = GifItemView.onFavChanged(gifComponent.getScopedContext());
    
    // Dispatch the event
    handler.dispatchEvent(new FavChangeEvent(!isLiked, gif.getId()));
  }

}

FullScreenComponentSpec.java

@LayoutSpec(events = { LikeChangeEvent.class })
public class FullScreenComponentSpec {

  private static final String TAG = "FullScreenComponent";

  @OnCreateInitialState
  static void createInitialState(ComponentContext c, StateValue<Boolean> isLiked, @Prop boolean initLiked) {
    isLiked.set(initLiked);
  }

  @OnCreateLayout
  static ComponentLayout onCreateLayout(ComponentContext context, @Prop RequestManager glide, @Prop GifItem gif, @State boolean isLiked) {
    ... create component view here
  }

  @OnUpdateState
  static void updateLikeButton(StateValue<Boolean> isLiked, @Param boolean updatedValue) {
    isLiked.set(updatedValue);
  }

  @OnEvent(ClickEvent.class)
  static void onLikeButtonClicked(ComponentContext c, @State boolean isLiked, @Prop GifItem gif) {
    FullScreenComponent.updateLikeButtonAsync(c, !isLiked);
    // Using event (instead of a simple callback) to update database 
    FullScreenComponent.dispatchLikeChangeEvent(FullScreenComponent.getLikeChangeEventHandler(c), !isLiked, gif.getId());
    
    // Send an event to update `isLiked` state of GitItemView component.
    // Create FavChangeEvent
    EventHandler<FavChangeEvent> handler = GifItemView.onFavChanged(c);
    // Dispatch the event
    handler.dispatchEvent(new FavChangeEvent(!isLiked, gif.getId()));
  }

}

GifItemViewSpec-1.java

@LayoutSpec(events = { LikeChangeEvent.class })
public class GifItemViewSpec {

  ... other stuff

  @OnUpdateState
  static void updateLikeButton(StateValue<Boolean> isLiked, @Param boolean updatedValue) {
    isLiked.set(updatedValue);
  }

  @OnEvent(ClickEvent.class)
  static void onLikeButtonClicked(ComponentContext c, @State boolean isLiked, @Prop GifItem gif) {
    GifItemView.dispatchLikeChangeEvent(GifItemView.getLikeChangeEventHandler(c), !isLiked, gif.getId());
    GifItemView.updateLikeButtonAsync(c, !isLiked);
  }

  @OnEvent(ClickEvent.class)
  static void onViewClicked(ComponentContext c, @Prop GifItem gif, @Prop (optional = true) GifCallback callback) {
    if (callback != null) {
      // Send component to callback
      callback.onGifSelected(gif, c.getComponentScope());
    }
  }

  @OnEvent(FavChangeEvent.class)
  static void onFavChanged(ComponentContext c, @FromEvent boolean isLiked, @FromEvent String gifId, @Prop GifItem gif) {
    if (gif.getId().equals(gifId)) {
      GifItemView.updateLikeButtonAsync(c, isLiked);
    }
  }

  public interface GifCallback {
    void onGifSelected(GifItem gif, Component gifComponent);
  }
}

GifItemViewSpec.java

@LayoutSpec(events = { LikeChangeEvent.class })
public class GifItemViewSpec {

  @OnCreateInitialState
  static void createInitialState(ComponentContext c, StateValue<Boolean> isLiked, @Prop boolean initLiked) {
    isLiked.set(initLiked);
  }

  @OnCreateLayout
  static ComponentLayout onCreateLayout(ComponentContext context, @Prop GifItem gif,
                      @Prop RequestManager glide, @State boolean isLiked) {

    ... create component view here
  }

  @OnUpdateState
  static void updateLikeButton(StateValue<Boolean> isLiked, @Param boolean updatedValue) {
    isLiked.set(updatedValue);
  }

  @OnEvent(ClickEvent.class)
  static void onLikeButtonClicked(ComponentContext c, @State boolean isLiked, @Prop GifItem gif) {
    GifItemView.dispatchLikeChangeEvent(GifItemView.getLikeChangeEventHandler(c), !isLiked, gif.getId());
    GifItemView.updateLikeButtonAsync(c, !isLiked);
  }
  
  @OnEvent(ClickEvent.class)
  static void onViewClicked(ComponentContext c, @Prop GifItem gif, @Prop (optional = true) GifCallback callback) {
    if (callback != null) {
      callback.onGifSelected(gif);
    }
  }

  @OnEvent(FavChangeEvent.class)
  static void onFavChanged(ComponentContext c, @FromEvent boolean isLiked, @FromEvent String gifId, @Prop GifItem gif) {
    if (gif.getId().equals(gifId)) {
      // This will invoke updateLikeButton which will update isLiked state.
      GifItemView.updateLikeButtonAsync(c, isLiked);
    }
  }
  
  ... some more stuff

  public interface GifCallback {
    void onGifSelected(GifItem gif);
  }
}