ComponentsRecyclerAdapter

This library provides ComponentsRecyclerAdapter, the subclass of RecyclerView.Adapter. Using it, you can easily create RecyclerView with multiple view types, or with complex data hierarchy.

Problems resolved by this library

You may face following problems associated with RecyclerView when you use a simple subclass inheriting RecyclerView.Adapter.

If multiple view types are used (not only one view type), it's needed to be conscious of a relation between a view type and a class of a view holder at more than one part.
It's hard to handle complex data structure to display composed of multiple data sets.
- e.g.
  - displaying items in a data set followed by items in another data set,
  - displaying a section header, a “read more” button or a progress bars,
  - displaying a item with a special type in the middle of items of other data set,
  - etc.

This library provides a solution for these problems.

Usage

First, you need to define a subclass of the ViewHolder class and its factory. Typically, it becomes as follows.

public class ContentViewHolder extends RecyclerView.ViewHolder {
    /** Factory will be used from RecyclerView.Adapter#onCreateViewHolder method. */
    public static final ViewHolderFactory<ContentViewHolder> FACTORY =
            new ViewHolderFactory<ContentViewHolder>() {
                @Override public ContentViewHolder createViewHolder(ViewGroup parent) {
                    TextView v = (TextView) LayoutInflater.from(parent.getContext())
                            .inflate(R.layout.item_content, parent, false);
                    return new ContentViewHolder(v);
                }
            };

    public final TextView textView;

    public ContentViewHolder(TextView itemView) {
        super(itemView);
        textView = itemView;
    }
}

A subclass of the Binder class also need to be defined.

public class StringContentBinder implements Binder<ContentViewHolder, String> {
    public static final StringContentBinder INSTANCE = new StringContentBinder();

    @Override
    public void bindViewHolder(ContentViewHolder h, Component<String> c, int posInComponent) {
        h.updateText(c.getItem(posInComponent));
    }
}

Then you can write an adapter class using these classes.

public class MyAdapter extends ComponentsRecyclerAdapter {
    /** Registry of ViewHolderFactories. This object should be passed to a constructor of a super class. */
    public static final ViewTypes VIEW_TYPES = new ViewTypes();
    public static class ViewTypes extends ViewHolderFactoryRegistry {
        public final ViewType<ContentViewHolder> content = register(ContentViewHolder.FACTORY);
    }

    /** Components refers a list of strings. */
    private final ListReferenceComponent<String> mStringListComponent = ListReferenceComponent.create(
        // This parameter specifies a view type and a binder to an item respectively.
        // In this example, a view type of all items is a `content`, and a binder of these is a `StringContentBinder`.
        // (It's possible to designate a view type and a binder differently for each item.)
        new FixedViewTypeBinderPairProvider<>(VIEW_TYPES.content, StringContentBinder.INSTANCE)
    );
    // You can other components to represents complex data structure to display.

    public MyAdapter(List<String> list) {
        super(VIEW_TYPES);
        // Set a passed list to the component.
        mStringListComponent.setList(list);
        // Set the component as a root component.
        // (You can create a hierarchy of components here.)
        setComponent(mStringListComponent);
    }
}

Demo project

Please see the ExampleAdapter class in the demo project.

The demo project has the ExampleAdapterOldStyle class also, which provides functions equivalent to the ExampleAdapter class using normal RecyclerView.Adapter class. Seeing it, you will contrast adapter in this library with normal one.

License

Copyright 2016 NOBUOKA Yu

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.

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Smart Adapters Library by Nacho López
recyclerview-binder by Satoru Fujiwara

kaiinui / ComponentsRecyclerAdapter