Renderers

Are you bored of creating adapters again and again when you have to implement a ListView or a RecyclerView?

Are you bored of using ViewHolders and create getView/onCreateViewHolder/onBindViewHolder methods with thousands of lines full of if/else if/else sentences?

Renderers is an Android library created to avoid all the Adapter/ListView/RecyclerView boilerplate needed to create a new adapter and all the spaghetti code that developers used to create following the ViewHolder classic implementation.

This Android library offers you two main classes to instantiate or extend and create your own rendering algorithms out of your adapter implementation.

Renderers is an easy way to work with android ListView/RecyclerView and Adapter classes. With this library you only have to create your Renderer classes and declare the mapping between the object to render and the Renderer. The Renderer will use the model information to draw your user interface.

You can find implementation details in this talks:

Software Design Patterns on Android Video

Software Design Patterns on Android Slides

Screenshots

Usage

To use Renderers Android library and get your ListView/RecyclerView working you only have to follow three steps:

1. Create your Renderer class or classes extending Renderer<T>. Inside your Renderer classes you will have to implement some methods to inflate the layout you want to render and implement the rendering algorithm.

public class VideoRenderer extends Renderer<Video> {

       @InjectView(R.id.iv_thumbnail)
       ImageView thumbnail;
       @InjectView(R.id.tv_title)
       TextView title;
       @InjectView(R.id.iv_marker)
       ImageView marker;
       @InjectView(R.id.tv_label)
       TextView label;

       @Override
       protected View inflate(LayoutInflater inflater, ViewGroup parent) {
           View inflatedView = inflater.inflate(R.layout.video_renderer, parent, false);
           ButterKnife.inject(this, inflatedView);
           return inflatedView;
       }

       @OnClick(R.id.iv_thumbnail)
       void onVideoClicked() {
           Video video = getContent();
           Log.d("Renderer", "Clicked: " + video.getTitle());
       }

       @Override
       protected void render() {
           Video video = getContent();
           renderThumbnail(video);
           renderTitle(video);
           renderMarker(video);
           renderLabel();
       }

       private void renderThumbnail(Video video) {
           Picasso.with(context).load(video.getResourceThumbnail()).placeholder(R.drawable.placeholder).into(thumbnail);
       }

       private void renderTitle(Video video) {
           this.title.setText(video.getTitle());
       }

       protected TextView getLabel() {
           return label;
       }

       protected ImageView getMarker() {
           return marker;
       }
       
       //If you don't use ButterKnife you have to implement these methods.
       
       /**
        * Maps all the view elements from the xml declaration to members of this renderer.
        */
       @Override protected void setUpView(View rootView) {
        /*
         * Empty implementation substituted with the usage of ButterKnife library by Jake Wharton.
         */
       }

       /**
        * Insert external listeners in some widgets.
       */
       @Override protected void hookListeners(View rootView) {
        /*
         * Empty implementation substituted with the usage of ButterKnife library by Jake Wharton.
         */
       }
}

You can use Jake Wharton's Butterknife library to avoid findViewById calls inside your Renderers if you want. But the usage of third party libraries is not mandatory.

1. Instantiate a RendererBuilder with a Renderer.

Renderer<Video> renderer = new LikeVideoRenderer();
RendererBuilder<Video> rendererBuilder = new RendererBuilder<Video>(renderer);

If you need to map different object instances to different Renderer implementations you can use RendererBuilder.bind methods:

RendererBuilder<Video> rendererBuilder = new RendererBuilder<Video>()
        .bind(Video.class, new LikeVideoRenderer());

If your binding is more complex and it's not based on different classes but in properties of these classes you can also extend RendererBuilder and override getPrototypeClass to customize your binding:

public class VideoRendererBuilder extends RendererBuilder<Video> {

  public VideoRendererBuilder() {
    Collection<Renderer<Video>> prototypes = getVideoRendererPrototypes();
    setPrototypes(prototypes);
  }

  /**
   * Method to declare Video-VideoRenderer mapping.
   * Favorite videos will be rendered using FavoriteVideoRenderer.
   * Live videos will be rendered using LiveVideoRenderer.
   * Liked videos will be rendered using LikeVideoRenderer.
   *
   * @param content used to map object-renderers.
   * @return VideoRenderer subtype class.
   */
  @Override
  protected Class getPrototypeClass(Video content) {
    Class prototypeClass;
    if (content.isFavorite()) {
      prototypeClass = FavoriteVideoRenderer.class;
    } else if (content.isLive()) {
      prototypeClass = LiveVideoRenderer.class;
    } else {
      prototypeClass = LikeVideoRenderer.class;
    }
    return prototypeClass;
  }

  /**
   * Create a list of prototypes to configure RendererBuilder.
   * The list of Renderer<Video> that contains all the possible renderers that our RendererBuilder
   * is going to use.
   *
   * @return Renderer<Video> prototypes for RendererBuilder.
   */
  private List<Renderer<Video>> getVideoRendererPrototypes() {
    List<Renderer<Video>> prototypes = new LinkedList<Renderer<Video>>();
    LikeVideoRenderer likeVideoRenderer = new LikeVideoRenderer();
    prototypes.add(likeVideoRenderer);

    FavoriteVideoRenderer favoriteVideoRenderer = new FavoriteVideoRenderer();
    prototypes.add(favoriteVideoRenderer);

    LiveVideoRenderer liveVideoRenderer = new LiveVideoRenderer();
    prototypes.add(liveVideoRenderer);

    return prototypes;
  }
}

1. Initialize your ListView or RecyclerView with your RendererBuilder and your AdapteeCollection instances inside your Activity or Fragment. You can use ListAdapteeCollection or create your own implementation creating a class which implements AdapteeCollection to configure your RendererAdapter or RVRendererAdapter.

private void initListView() {
    adapter = new RendererAdapter<Video>(rendererBuilder, adapteeCollection);
    listView.setAdapter(adapter);
}

private void initListView() {
    adapter = new RVRendererAdapter<Video>(rendererBuilder, adapteeCollection);
    recyclerView.setAdapter(adapter);
}

Remember if you are going to use RecyclerView instead of ListView you'll have to use RVRendererAdapter instead of RendererAdapter.

Usage

Download the project, compile it using mvn clean install import renderers-3.0.0.aar into your project.

Or declare it into your pom.xml

<dependency>
    <groupId>com.github.pedrovgs</groupId>
    <artifactId>renderers</artifactId>
    <version>3.0.0</version>
    <type>aar</type>
</dependency>

Or into your build.gradle

dependencies{
    compile 'com.github.pedrovgs:renderers:3.0.0'
}

Developed By

Pedro Vicente Gómez Sánchez - pedrovicente.gomez@gmail.com

License

Copyright 2016 Pedro Vicente Gómez Sánchez

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

miroslavign / Renderers

Renderers

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