JarCastingRecyclerView Adapter
This library is designed to help separate the creation and binding of views being adapted by a RecyclerView Adapter, from the Adapter itself.
Instead of writing an Adapter that needs to know which layout resource(s) to inflate for the items, as well as binding logic and click listeners, this library allows you to write a ViewModel class which wraps your data model, defining how the view should be created, bound, how many spans it should take up, etc. You no longer need to write a RecyclerView Adapter class at all.
Creating headers and footers now becomes as simple as creating a HeaderViewModel and FooterViewModel class, and adding them to you dataset:
List<ViewModel> items = new ArrayList<>();
items.add(headerViewModel);
items.addAll(myItemViewModels);
items.add(footerViewModel);
viewModelAdapter.setItems(items);
The adapter supports diffing between different sets of ViewModels (via the ContentsComparator interface). Diff results are automatically calculated (on the background thread) and supplied to the ViewModelAdapter, which performs the appropriate remove, move & insert RecyclerView animations.
SpanSizeLookup can be applied to a GridLayoutManager, meaning the span size can be defined in the ViewModel.
Gradle
compile 'com.simplecityapps:recyclerview-adapter:1.0.1'
Usage
See the sample app for a very basic example.
When you need an adapter, create a new instance of ViewModelAdapter and pass it to your RecyclerView via setAdapter.
Create a ViewModel, to wrap the model you're going to display in the RecyclerView. You'll also need to create a ViewHolder.
For example, a ViewModel that just wraps a string:
// First generic type param is the model, second is the ViewHolder
public class ItemViewModel extends BaseViewModel<String, ItemViewModel.ViewHolder>
// Our 'model'
String text;
// Constructor - force ourselves to pass our model in.
public ItemViewModel(String text){
this.text = text;
}
// The ViewHolder to be used for our ItemViewModel/
// This doesn't have to subclass BaseViewHolder, we just get a few perks if it does.
static class ViewHolder extends BaseViewHolder<ItemViewModel> {
// View Holder implementation
TextView textView;
// ...
}
Now just let implement the required methods using Android Studio's auto-fix feature. (Alt + Enter)
Now it's time to define how the ViewModel will present itself to the Adapter.
Specify which layout id will be used. Note: If you prefer to create layouts programmatically, you don't need to override this method. You will need to override getViewType() though.
@Override
public int getLayoutResId() {
return R.layout.list_item;
}
Create an instance of the ViewHolder
@Override
public ViewHolder createViewHolder(ViewGroup parent) {
return new ViewHolder(createView(parent));
}
Define how the ViewHolder should be bound
@Override
public void bindView(ViewHolder holder) {
super.bindView(holder);
// Bind our model (text) to our holder views.
holder.textView.setText(text);
}
OK, now we've created a ViewHolder, defined which layout we're going to use and how the model should be bound to the ViewHolder views. We're ready to go.
Back in our controller (Activity/Fragment/ViewGroup/whatever), we just attach a ViewModelAdapter to the RecyclerView:
ViewModelAdapter adapter = new ViewModelAdapter();
recyclerView.setAdapter(adapter);
Let's say we have an array of Strings we want to adapt:
String[] strings = new String[] {
"Ethereum", "Monero", "Zcash", "Dash", "Bitcoin", "LiteCoin", "Golem", "Sia"
}
We just need to create a List of ItemViewModels to wrap our strings, and pass that to the adapter:
List<ViewModel> viewModels = new ArrayList<>();
for (String string: strings){
viewModels.add(new ViewModel(string));
}
adapter.setItems(viewModels);
That's it! You can create as many different types of ViewModels as you wish. You no longer need to create RecyclerView Adapters to define how the items should be presented.
Sample app screenshot:
License
Recycler Adapter is released under the Apache 2.0 License , which can be found here: License