smart-recycler-adapter

Never code any boilerplate RecyclerAdapter again!
This library will make it easy and painless to map your data item with a target ViewHolder.

Features

OnViewEventListener

• Smart OnClick / OnLongClickListener ^{SimpleItemOnClickOnLongClickActivity}
• State holding with OnItemSelectedListener ^{MultipleViewTypesResolverActivity}
• Custom View Events ^{CustomViewEventActivity}

ItemTouchHelper Swipe, Drag & Drop extensions

• Drag & drop ^{DragAndDropItemActivity}
• Drag & drop with handle ^{DragAndDropHandleItemActivity}
• Swipe to remove item ^{SwipeRemoveItemActivity}
• Drag & drop, Swipe, View Events ^{MultipleEventsAndExtensionsActivity}
• Grid + Drag & drop ^GridActivity

ViewTypeResolver

• Multiple ViewHolder types resolver ^{MultipleViewTypesResolverActivity}

SmartStateHolder

• Multiple items select ^{MultiSelectItemsActivity}
• Single RadioButton select ^{SingleSelectRadioButtonItemActivity}
• Multiple CheckBox select ^{MultiSelectCheckBoxItemsActivity}
• Multiple Switch select ^{MultiSelectSwitchItemsActivity}
• Multiple Expandable items ^{MultipleExpandableItemActivity}
• Single Expandable item ^{SingleExpandableItemActivity}

Nested adapter

• Nested SmartRecyclerAdapter ^{NestedSmartRecyclerAdaptersActivity}

Pagination

• Endless scroll ^{EndlessScrollActivity}
• Endless scroll with load more button ^{EndlessScrollLoadMoreButtonActivity}

DiffUtil

• Diff Util extension ^{DiffUtilActivity}

Release overview

• Kotlin + AndroidX (jcenter, jitpack) v4.0.0
• Java + AndroidX (jcenter, jitpack) v3.0.0
• Java + AppCompat (jitpack) v2.2.0

Gradle

Add jcenter() or maven { url "https://dl.bintray.com/manneohlund/maven" } to your build.gradle under repositories

dependencies {
  implementation 'io.github.manneohlund:smart-recycler-adapter:4.1.0'
}

Basic

Basic adapter creation

SmartRecyclerAdapter
  .items(items)
  .map(MoviePosterModel::class, PosterViewHolder::class)
  .map(MovieBannerModel::class, BannerViewHolder::class)
  .map(MovieModel::class, MovieViewHolder::class)
  .map(TopNewsModel::class, TopNewsViewHolder::class)
  .into<SmartRecyclerAdapter>(recyclerView)

SmartViewHolder

Just extend your ViewHolder class with SmartViewHolder and pass in the target type ex SmartViewHolder<Mail>.
Note that the constructor can both take View or ViewGroup as parameter, in this case PosterViewHolder(ViewGroup parentView) to avoid casting to ViewGroup while inflating.
The parentView is the recyclerView.
The method unbind has an default implementation and is optional.

Works with Android DataBinding! Just add the DataBinding LayoutInflater in super call. 🚀

class PosterViewHolder(parentView: ViewGroup) : SmartViewHolder<MovieModel>(
    LayoutInflater.from(parentView.context).inflate(R.layout.poster_item, parentView, false)
) {

  override fun bind(movie: MovieModel) {
    Glide.with(imageView)
      .load(model.posterUrl)
      .into(imageView)
  }
  
  override fun unbind() {
    Glide.with(imageView).clear(imageView)
  }
} 

View Events

You can easily assign events to views and add an OnViewEventListener to the SmartRecyclerAdapter for easy event handling.

SmartRecyclerAdapter
  .items(items)
  .map(MovieModel::class, MovieViewHolder::class)
  // Adds a basic `OnViewEventListener` to any `SmartViewHolder` extension that implements `ViewEventListenerHolder`
  .addViewEventListener(onViewEventListener { view, viewEventId, position -> handleItemEvent()})
  .into<SmartRecyclerAdapter>(recyclerView)

In your view holder, add eg OnClickListener to a view and call onViewEvent on the OnViewEventListener.
Your ViewHolder must implements ViewEventListenerHolder to receive the OnViewEventListener.

open class SimpleItemViewHolder(parentView: ViewGroup) : SmartViewHolder<Int>(
        LayoutInflater.from(parentView.context).inflate(R.layout.simple_item, parentView, false)
), ViewEventListenerHolder {

  override lateinit var viewEventListener: OnViewEventListener

  init {
    itemView.setOnClickListener { view ->
      viewEventListener.onViewEvent(view, R.id.action_play_movie, adapterPosition)
    }
  }

  override fun bind(item: Int) {
    // Handle binding
  }
}

Kotlin has no SAM constructors so instead of writing interface instantiation you can utilize lambda helper methods for all predefined library event listeners ex:

.addViewEventListener(onViewEventListener { view, viewEventId, position ->
  // Handle event
})

is same as

.addViewEventListener(object : OnViewEventListener {
  override fun onViewEvent(view: View, viewEventId: ViewEventId, position: Position) {
    // Handle event
    }
})

Predefined Listeners in the lib

If you are lazy and want to auto assign a predefined onClickListener and onLongClickListener with viewEventIds R.id.event_on_click and R.id.event_on_long_click,

Define listeners for MovieViewHolder

Default implemented view event id for OnItemClickListener is R.id.event_on_click. Default implemented view id for OnItemClickListener is R.id.undefined. R.id.undefined targets root view of the ViewHolder (ViewHolder.itemView).

interface OnMovieItemClickListener : OnItemClickListener {
  override val viewHolderType: SmartViewHolderType
    get() = MovieViewHolder::class
}

SmartRecyclerAdapter will automatically bind an View.OnClickListener to a view with id R.id.movie_info_button.

interface OnMovieInfoButtonClickListener : OnItemClickListener {
  override val viewHolderType: SmartViewHolderType
    get() = MovieViewHolder::class

  override val viewId: ViewId
    get() = R.id.movie_info_button
}

And add event listener to SmartRecyclerAdapter builder.

SmartRecyclerAdapter
  .items(items)
  .map(HeaderModel::class, HeaderViewHolder::class)
  .map(MovieModel::class, MovieViewHolder::class)
  .map(MovieTrailerModel::class, MovieTrailerViewHolder::class)
  // Adds `OnItemClickListener` and auto binds `View.OnClickListener` on all ViewHolders.
  .addViewEventListener(onItemClickListener { view, viewEventId, position -> handleEvent(viewEventId) })
  // Adds event listener for MovieViewHolder only and overrides any generic `OnItemClickListener`
  .addViewEventListener(object : OnMovieItemClickListener {
    override fun onViewEvent(view: View, viewEventId: ViewEventId, position: Position) {
      playMovie()
    }
  })
  // Adds event listener for MovieViewHolder only and auto binds `View.OnClickListener` on view with id `R.id.movie_info_button`
  .addViewEventListener(object : OnMovieInfoButtonClickListener {
    override fun onViewEvent(view: View, viewEventId: ViewEventId, position: Position) {
      showMovieInfo(position)
    }
  })
  .into<SmartRecyclerAdapter>(recyclerView)

Adapter creation with ViewTypeResolver

If you want to bind one data type with different view holders depending on some attribute you can set a ViewTypeResolver.
Note .map() call not needed in this case but you can combine if you want to.

SmartRecyclerAdapter
  .items(items)
  .setViewTypeResolver{ item, position -> {
    when { 
      item is MovieTrailerModel -> MovieTrailerViewHolder::class
      item is MovieModel && item.isRatedR() -> RMovieViewHolder::class
      else -> MovieViewHolder::class // Add default view if needed, else SmartRecyclerAdapter will look at the base `.map` mapping
    }
  }}
  .into<SmartRecyclerAdapter>(recyclerView)

New nested SmartRecyclerAdapter from v2.0.0

New in SmartRecyclerAdapter v2.0.0 is support for nested recycler adapter. Now you can easily build complex nested adapters without hustle and have full control of the adapter in your view controlling Fragment or Activity. Use the new create() method instead of the into(recyclerView) to create just the SmartRecyclerAdapter then set the adapter to the recycler view in your ViewHolder. Just implement the SmartAdapterHolder interface in your ViewHolder and SmartRecyclerAdapter will handle the mapping.

1. Create your nested SmartRecyclerAdapter

val myWatchListSmartMovieAdapter: SmartRecyclerAdapter = SmartRecyclerAdapter
  .items(myWatchListItems)
  .map(MovieModel::class, ThumbViewHolder::class)
  .addViewEventListener(onItemClickListener { view, viewEventId, position -> playMovie() })
  .create()

2. Map myWatchListSmartMovieAdapter with MyWatchListViewHolder

SmartRecyclerAdapter
  .items(items)
  .map(MoviePosterModel::class, PosterViewHolder::class)
  .map(MyWatchListModel::class, MyWatchListViewHolder::class)
  .map(MyWatchListViewHolder::class, myWatchListSmartMovieAdapter)
  .into<SmartRecyclerAdapter>(recyclerView)

3. Map myWatchListSmartMovieAdapter to MyWatchListViewHolder

class MyWatchListViewHolder : SmartViewHolder<MyWatchListModel>, SmartAdapterHolder {
    
  override var smartRecyclerAdapter: SmartRecyclerAdapter? = null
    set(value) {
      field = value
      recyclerView.layoutManager = LinearLayoutManager(recyclerView.context, HORIZONTAL, false)
      recyclerView.adapter = value
    }

  override fun bind(myWatchListModel: MyWatchListModel) {
    // bind model data to views
  }
    
  override fun unbind() {
    // optional unbinding of view data model
  }
}

SmartEndlessScrollRecyclerAdapter

A popular feature in apps is to have endless scrolling with pagination, in other words load more items when user has scrolled to bottom. With SmartEndlessScrollRecyclerAdapter you can achieve this.

1. Create adapter

val endlessScrollAdapter: SmartEndlessScrollRecyclerAdapter = SmartEndlessScrollRecyclerAdapter
  .items(items)
  .map(MovieModel::class, MovieViewHolder::class)
  .into(recyclerView)

2. Set OnLoadMoreListener to your SmartEndlessScrollRecyclerAdapter

Called when scrolled to the last item and loading view is visible.

endlessScrollAdapter.setOnLoadMoreListener{
  endlessScrollAdapter.addItems(moreItems)
}

More SmartEndlessScrollRecyclerAdapter features

Enable/Disable endless scrolling and thus removing the loading view. endlessScrollAdapter.isEndlessScrollEnabled = false

You can also set your custom loading/loadmore view. endlessScrollAdapter.setCustomLoadMoreLayoutResource(R.layout.your_custom_loadmore_view);

More

For more samples test out the sample app and see the source code.

RecyclableViewHolder

Sometimes a ViewHolder created by the Adapter cannot be recycled due to its transient state. In order to fix this is to implement RecyclableViewHolder in your SmartViewHolder extension so that upon receiving this callback, Adapter can clear the animation(s) that effect the View's transient state and return true so that the View can be recycled.

class MovieViewHolder : SmartViewHolder, RecyclableViewHolder {
  override fun onFailedToRecycleView(): Boolean = true
}

OnViewAttachedToWindowListener and OnViewDetachedFromWindowListener

If you want to catch when the view is attached and detached from the window in your ViewHolder you can implement OnViewAttachedToWindowListener and OnViewDetachedFromWindowListener in your SmartViewHolder extension. Becoming detached from the window is not necessarily a permanent condition the consumer of an Adapter's views may choose to cache views offscreen while they are not visible, attaching and detaching them as appropriate.

class MovieViewHolder : SmartViewHolder, 
    OnViewAttachedToWindowListener, 
    OnViewDetachedFromWindowListener { 

  override fun onViewAttachedToWindow(viewHolder: RecyclerView.ViewHolder) {
    // Restore
  }

  override fun onViewDetachedFromWindow(viewHolder: RecyclerView.ViewHolder) {
    // Cache
  }
}

Migrations

More guides coming to the Wiki Page

ViewEvent Migration

Old way before v3.0.0

Variable parameter overloading with many different addViewEventListener calls.

.addViewEventListener(
    MovieViewHolder.class,
    R.id.event_on_click,
    (view, viewEventId, position) -> playMovie())

class MovieViewHolder
    extends SmartAutoEventViewHolder<MyWatchListModel>
    implements SmartAdapterHolder {}

New in v3.0.0

Create an OnItemClickListener for MovieViewHolder. SmartAutoEvent implementations has been removed so no need for ex MovieViewHolder to extend SmartAutoEventViewHolder.

interface OnMovieItemClickListener extends OnItemClickListener {
  @NonNull
  @Override
  default Class<? extends SmartViewHolder> getViewHolderType() {
    return MovieViewHolder.class;
  }
}

Add listener to the SmartAdapterBuilder.

.addViewEventListener((OnMovieItemClickListener) (view, viewEventId, position) -> playMovie())

New in v4.0.0 (Kotlin)

In Kotlin the interface properties are overridden instead of default methods as in java. SmartViewHolderType is a typealias of KClass<out SmartViewHolder<*>>.

interface OnMovieItemClickListener : OnItemClickListener {
  override val viewHolderType: SmartViewHolderType
    get() = MovieViewHolder::class
}

.addViewEventListener(object : OnMovieItemClickListener {
  override fun onViewEvent(view: View, viewEventId: ViewEventId, position: Position) {
    playMovie()
  }
})

---

Kotlin has no SAM constructor for interface as java so lambda resolving is not working yet. However you can do lambda call to eg OnItemClickListener extensions like this:

inline fun onMovieItemClickListener(crossinline viewEvent: (
        view: View,
        viewEventId: ViewEventId,
        position: Position) -> Unit) = object : OnItemClickListener {
    override fun onViewEvent(view: View, viewEventId: ViewEventId, position: Position) {
        viewEvent(view, viewEventId, position)
    }
}

.addViewEventListener(onMovieItemClickListener { view, viewEventId, position -> playMovie() })

More SmartRecyclerAdapter features

val adapter: SmartRecyclerAdapter = SmartRecyclerAdapter
    .items(items)
    .map(MovieModel::class, MovieViewHolder::class)
    .into(recyclerView)

// We can add more data
adapter.addItems(items)

// Add data at index with animation
adapter.addItem(0, item)

// Add data at index without animation
adapter.addItem(0, item, false)

// Remove item at index with animation
adapter.removeItem(0)

// Remove item at index without animation
adapter.removeItem(0, false)

// Replace item at index with animation
adapter.replaceItem(0, item)

// Replace item at index without animation
adapter.replaceItem(0, item, false)

// Get items by type
adapter.getItems(MovieModel::class)

// Delete all items in the list
adapter.clear()