murdly / partdefiner

Define parts of your complicated view and render each part as separate item in your RecyclerView or ListView.

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>