saleehk / binding-collection-adapter

Easy way to bind collections to listviews and recyclerviews with the new Android Data Binding framework

BindingCollectionAdapter

Easy way to bind collections to listviews and recyclerviews with the new Android Data Binding framework.

Download

compile 'me.tatarka:bindingcollectionadapter:0.8'

Usage

You need to provied your items and an ItemView to bind to the layout. You should use an ObservableList to automaticaly update your view based on list changes. However, you can use any Collection if you don't need that functionality.

public class ViewModel {
  public final ObservableList<String> items = new ObservableArrayList<>();
  public final ItemView itemView = ItemView.of(BR.item, R.layout.item);
}

Then bind it to the collection view with app:items and app:itemView. There are also some convience factories to attach a LayoutManager to a RecyclerView with app:layoutManager.

<!-- layout.xml -->
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
      <variable name="viewModel" type="com.example.ViewModel"/> 
      <import type="me.tatarka.bindingcollectionadapter.LayoutManagers" />
    </data>
    
    <ListView
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      app:items="@{viewModel.items}"
      app:itemView="@{viewModel.itemView}"/>
      
    <android.support.v7.widget.RecyclerView
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      app:layoutManager="@{LayoutManagers.linear()}"
      app:items="@{viewModel.items}"
      app:itemView="@{viewModel.itemView}"/>
      
    <android.support.v4.view.ViewPager
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      app:items="@{viewModel.items}"
      app:itemView="@{viewModel.itemView}"/>
</layout>

In your item layout, the collection item will be bound to the variable with the name you passed into the ItemView

<!-- item.xml -->
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
      <variable name="item" type="String"/> 
    </data>
    
    <TextView
      android:id="@+id/text"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:text="@{item}"/>
</layout>

Multiple View Types

You can use multiple view types by using a ItemViewSelector instead. You can still bind it to the view with app:itemView.

public final ItemViewSelector<String> itemView = new BaseItemViewSelector<String>() {
    @Override
    public void select(ItemView itemView, int position, String item) {
        itemView.set(BR.item, position == 0 ? R.layout.item_header : R.layout.item);
    }
    
    // This is only needed if you are using a BindingListViewAdapter
    @Override
    public int viewTypeCount() {
      return 2;
    }
};

Note that select is called many times so you should not do any complex processing in there. If you don't need to bind an item at a specific position (a static footer for example) you can use ItemView.BINDING_VARIABLE_NONE as the binding varibale.

Additonal Adapter Configuration

BindingListViewAdapter

You can set a callback to give an id for each item in the list with

adapter.setItemIds(new BindingListViewAdapter.ItemIds<T>() {
    @Override
    public long getItemId(int position, T item) {
        return // Calculate item id.
    }
});

or by defining app:itemIds="@{itemIds}" in the ListView in your layout file.

Setting this will make hasStableIds return true which can increase performace of data changes.

You can also define a different dropdown view layout by setting

itemView.setLayoutRes(BindingListViewAdapter.DROP_DOWN_LAYOUT, R.layout.item_dropdown);

BindingViewPagerAdapter

You can set a callback to give a page title for each item in the list with

adapter.setPageTitles(new PageTitles<T>() {
    @Override
    public CharSequence getPageTitle(int position, T item) {
        return "Page Title";
    }
});

or by defining app:pageTitles="@{pageTitles}" in the ViewPager in your layout file.

Directly manipulationg views

Data binding is awesome and all, but you may run into a case where you simply need to manipulate the views directly. You can do this without throwing away the whole of databinding by subclassing an exisiting BindingCollectionAdapter. You can then bind adapter in your layout to your subclass's class name to have it use that instead. Instead of overriding the nomral adapter methods, you should override onCreateBinding() or onBindBinding() and call super allowing you to run code before and after those events and get access to the item view's binding.

public class MyRecyclerViewAdapter<T> extends BindingRecyclerViewAdapter<T> {
    public LoggingRecyclerViewAdapter(@NonNull ItemView itemView) {
        super(itemView);
    }

    public LoggingRecyclerViewAdapter(@NonNull ItemViewSelector<T> selector) {
        super(selector);
    }

    @Override
    public ViewDataBinding onCreateBinding(LayoutInflater inflater, @LayoutRes int layoutId, ViewGroup viewGroup) {
        ViewDataBinding binding = super.onCreateBinding(inflater, layoutId, viewGroup);
        Log.d(TAG, "created binding: " + binding);
        return binding;
    }

    @Override
    public void onBindBinding(ViewDataBinding binding, int bindingVariable, @LayoutRes int layoutRes, int position, T item) {
        super.onBindBinding(binding, bindingVariable, layoutRes, position, item);
        Log.d(TAG, "bound binding: " + binding + " at position: " + position);
    }
}

<android.support.v7.widget.RecyclerView
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  app:layoutManager="{@LayoutManagers.linear()}"
  app:items="@{viewModel.items}"
  app:itemView="@{viewModel.itemView}"
  app:adapter='@{"com.example.MyRecyclerViewAdapter"}'/>

Known Issues

Cannot Resolve the libraries @BindingAdapter's

This is likely because you are using the android-apt plugin which broke this in previous versions. Update to 1.6+ to fix it.

License

Copyright 2015 Evan Tatarka

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.