partdefiner

Helps you split your RecyclerView or ListView items into separated parts.
Based on facebook article about Fast Rendering News Feed on Android.

Usage

Defining part

Step 1: create a custom view for your part

public class HeaderView extends RelativeLayout {

    @BindView(R.id.avatar) ImageView avatarView;
    @BindView(R.id.text_author) TextView authorView;
    @BindView(R.id.text_date) TextView dateView;

    public HeaderView(Context context) {
        super(context);
        ButterKnife.bind(this, inflate(context, R.layout.item_story_header, this));
    }

    public void setAvatarColor(int color) {
        avatarView.setBackgroundColor(color);
    }

    public void setTitle(String author) {
        authorView.setText(author);
    }

    public void setDate(String date) {
        dateView.setText(date);
    }
}

Step 2: implement a Binder which binds model with your custom view

public class HeaderBinder implements Binder<HeaderView> {

    private Story story;

    public HeaderBinder(Story model) {
        story = model;
    }

    @Override public void prepare(HeaderView view) { }

    @Override public void bind(HeaderView view) {
        view.setAvatarColor(story.avatarColor);
        view.setTitle(story.title);
        view.setDate(story.date);
    }

    @Override public void unbind(HeaderView view) { }
}

Step 3: wire them together by implementing SinglePartDefinition

public class HeaderPart implements SinglePartDefinition<Story, HeaderView> {
    @Override public int getViewType() {
        return ViewType.HEADER;
    }

    @Override public Binder<HeaderView> createBinder(Story model) {
        return new HeaderBinder(model);
    }

    @Override public boolean isNeeded(Story model) {
        return true;
    }
}

or if you need to group several parts into one, implement GroupPartDefinition instead:

public class EmbedPart implements GroupPartDefinition<Story> {

    @Override public boolean isNeeded(Story model) {
        return model.imagePreviewId != -1 || model.fileName != null;
    }

    @Override public List<PartDefinition<Story>> getChildren(Story model) {
        List<PartDefinition<Story>> parts = new ArrayList<>();
        parts.add(new ImageEmbedPart());
        parts.add(new FileEmbedPart());
        return parts;
    }
}

Step 4: use it with your adapter. See FeedAdapter.java in sample project.

Real life example app

See example code here. You can also download the app from google play:

Download

via Gradle:

compile 'com.akarbowy:partdefiner:1.0'

or Maven:

<dependency>
  <groupId>com.akarbowy</groupId>
  <artifactId>partdefiner</artifactId>
  <version>1.0</version>
</dependency>