This is an attempt to merge the forked infinity adapter and the DataBinding adapter from google ui toolkit devs.

infinity

Tiny library with ability to provide support for infinite paginated scrolling in RecyclerView. It is able to show loading & try again layout at the bottom of the list.

# Usage

Minimal implementation

1. Implement you own RecyclerView adapter which extends InfinityAdapter<Model, ViewHolder>

   public class SampleUserAdapter extends InfinityAdapter<User, ViewHolder> {
   
   	@Override
   	public ViewHolder onCreateContentViewHolder(ViewGroup parent, int viewType) {
   		LayoutInflater inflater = LayoutInflater.from(parent.getContext());
   		View view = inflater.inflate(R.layout.list_item_user, parent, false);
   		return new ViewHolder(view);
   	}
   
   	@Override
   	public void onBindContentViewHolder(ViewHolder holder, int position) {
   		((TextView) holder.itemView).setText(getContentItem(position).toString());
   	}
   
   	public class ViewHolder extends RecyclerView.ViewHolder {
   		public ViewHolder(View itemView) {
   			super(itemView);
   		}
   	}
   }

2. Create instance of `InfinityFiller<Model>` class. It serves as a paginated data provider to your adapter.

	```java 		
	InfinityFiller<User> filler = new InfinityFiller<User>() {
		@Override public void onLoad(final int limit, final int offset, final Callback<User> callback) {
			// Async data provider
			DataManager.get().getDataObservable(limit, offset)
					.subscribe(new Action1<List<User>>() {
						@Override public void call(List<User> users) {
							callback.onData(users); // call onData() when data available
						}
					}, new Action1<Throwable>() {
						@Override public void call(Throwable throwable) {
							callback.onError(throwable); // call onError() when error occurs
						}
					});
		}
	};
	```

3. Assign filler to adapter and start loading

	```java
	final SampleUserAdapter adapter = new SampleUserAdapter();
	recyclerView.setAdapter(adapter);
	adapter.setFiller(filler);
	adapter.start();
	```

## Handy features

### Change error/loading layout at the bottom of the list

Simply override method `getFooterLayout()` in your adapter and return XML layout resource what contains 2 views with id's `@+id/loading` and `@+id/retry`.

1. `footer_layout.xml`
	```xml
	<LinearLayout
		android:layout_width="match_parent"
		android:layout_height="wrap_content">
	
		<LinearLayout
			android:id="@+id/loading"
			android:layout_width="...">
	
			<!-- content -->
		</LinearLayout>
	
		<LinearLayout
			android:id="@+id/retry"
			android:layout_width="...">
	
			<!-- content -->
		</LinearLayout>
	</LinearLayout>
	```

2. Adapter class
	```java
		@Override
		public int getFooterLayout() {
			return R.layout.footer_layout;
		}
	```

### Event listener

If you want to know about data loading events, you can set event listener via `adapter.setEventListener()` method.

```java
adapter.setEventListener(new InfinityEventListener() {

	@Override public void onPreLoadFirst(boolean pullToRefresh) { }

	@Override public void onFirstLoaded(boolean pullToRefresh) { }

	@Override public void onFirstUnavailable(Throwable error, boolean pullToRefresh) { }

	@Override public void onFirstEmpty(boolean pullToRefresh) { }

	@Override public void onPreLoadNext() { }

	@Override public void onNextLoaded() { }

	@Override public void onNextUnavailable(Throwable error) { }

	@Override public void onFinished() { }
});

ViewType support

View types are supported by default. All you need to do is to override getContentItemViewType() method of your adapter class. View type value returned by this method must be in range <0,49>.

public static final int EVEN = 0;
public static final int ODD = 1;

@Override
public int getContentItemViewType(int position) {
	return position % 2 == 0 ? EVEN : ODD;
}

Header support

In scenario you want to add header (or headers) at the top of the recycler, implement particular methods in your adapter class.

public static final int HEADER_EVEN = 50;
public static final int HEADER_ODD = 51;

@Override public ViewHolder onCreateHeaderViewHolder(ViewGroup parent, int viewType) {
	if (viewType == HEADER_EVEN) {
		View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_header_type_1, parent, false);
		return new ViewHolder(view);
	} else {
		View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_header_type_2, parent, false);
		return new ViewHolder(view);
	}
}

@Override public void onBindHeaderViewHolder(RecyclerView.ViewHolder holder, int position) {
	// ...
}

@Override public int getHeaderCount() {
	return NUM_OF_HEADERS;
}

@Override public int getHeaderItemViewType(int position) {
	if (position == 0) {
		return HEADER_EVEN;
	} else {
		return HEADER_ODD;
	}
}

There are two limitations:

• Header view must share ViewHolder with content views. You can solve this problem by base ViewHolder.
• Header view type values must be in range <50, 100>

Download

dependencies {
	compile 'com.github.thefuntasty:infinity:1.0.0'
}

License

MIT License

Copyright (c) 2017 FUNTASTY Digital s.r.o.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
urnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.