ProperBaseAdapter

Straightforward, fast, easy to use and adaptable generic RecyclerView adapter. Never create another RecyclerView adapter again.

How does it work?

1. Define an AdapterItem representing an adapter item view type.

class ImageViewRecyclerItem(private val drawable: Drawable?): AdapterItem<ImageView>() {
    // here we define how view is created
    override fun getNewView(parent: ViewGroup): ImageView {
        return ImageView(parent.context)
    }
    // here we populate the view
    override fun onViewBound(view: ImageView) {
        view.setImageDrawable(drawable)
        view.scaleType = ImageView.ScaleType.CENTER
    }
}

or inflate your own view.

class TextRowRecyclerItem(private val text: String): AdapterItem<View>() {
    override fun getNewView(parent: ViewGroup): View {
        return getViewFromLayout(parent, android.R.layout.activity_list_item)
    }
    override fun onViewBound(view: View) {
        view.findViewById<TextView>(R.id.text1).text = text
    }
}

AdapterItem subscribes to callbacks you can override to fine-tune behaviour in different states.

override fun onItemViewAttached(view: YourView): Unit
override fun onItemViewDetached(view: YourView): Unit
override fun onItemViewRecycled(view: YourView): Unit
override fun onItemViewFailedToRecycle(view: YourView): Unit

and has a few public methods to help you fine tune behaviour of each item.

fun getView(): YourView
fun setAnimation(@AnimRes animation: Int): Unit
fun setClickListener(clickListener: View.OnClickListener?): Unit
fun setMargins(marginStart: Int = 0, marginTop: Int = 0, marginEnd: Int = 0, marginBottom: Int = 0): Unit
fun setIsStickyHeader(isStickyHeader: Boolean)
fun setViewTag(viewTag: Any?): Unit

2. Have your Activity, Fragment or View implement BaseRecyclerViewImplementation .

class MainActivity : AppCompatActivity(), ProperBaseAdapterImplementation {
  ...
  // library needs to know how to locate a RecyclerView
  override fun getRecyclerView(): RecyclerView? {
        return findViewById(R.id.recyclerView)
  }

  // add items to provided data list, those will be added to the adapter.
  override fun getAdapterData(data: MutableList<AdapterItem<*>>): MutableList<AdapterItem<*>> {
    // let's say we want to display an image on top
    data.add(ImageViewRecyclerItem(ContextCompat.getDrawable(this, android.R.drawable.btn_radio))
        .withTopBottomMargins(topMargin = resources.getDimensionPixelSize(R.dimen.dp16))
    // and add 10 text view items
    for (i in 1..10) {
        data.add(TextViewRecyclerItem("Text item $i")
            .withAllMargins(resources.getDimensionPixelSize(R.dimen.dp16))
            .withAnimation(R.anim.item_fall_down)
            .withClickListener(View.OnClickListener {
                Toast.makeText(this, "Clicked item $i", Toast.LENGTH_SHORT).show()
            }))
    }
    // and add another image on bottom
    data.add(ImageViewRecyclerItem(ContextCompat.getDrawable(this, android.R.drawable.ic_btn_speak_now)))

    return data
  }
  ...

3. Simply calling refreshRecyclerView method will do the rest and populate recycler view with provided data.

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    refreshRecyclerView()
}

You're of course not required use a provided BaseRecyclerViewImplementation and simply construct ProperBaseAdapter yourself and set it to your RecyclerView.

Make use of multiple adapter's public methods based on your needs:

fun getItemAt(position: Int): AdapterItem<*>?
fun getItemByViewTag(viewTag: Any): AdapterItem<*>?
fun getItemTypeAt(position: Int): KClass<*>
fun getPositionForItemWithViewTag(viewTag: Any): Int?

fun addItems(data: List<AdapterItem<*>>, index: Int = data.size, notifyItemRangeChanged: Boolean = true): Unit
fun setItems(data: List<AdapterItem<*>>, notifyDataSetChanged: Boolean = true): Unit
fun updateItems(data: List<AdapterItem<*>>): Unit
fun removeItems(fromPosition: Int, itemCount: Int = 1, notifyDataSetChanged: Boolean = true): Unit
fun removeAllItems(notifyDataSetChanged: Boolean = true): Unit

fun notifyItemWithViewTagChanged(viewTag: Any): Unit
fun hasStickyHeaders(): Boolean
fun setDefaultItemMargins(start: Int = 0, top: Int = 0, end: Int = 0, bottom: Int = 0): Unit
fun setDefaultItemSideMargins(@Px startAndEnd: Int): Unit

Nice! How do I get started?

Make sure root build.gradle repositories include JitPack

allprojects {
    repositories {
        maven { url 'https://jitpack.io' }
    }
}

And ProperBaseAdapter dependency is added to app build.gradle

dependencies {
    implementation "com.github.mvojtkovszky:ProperBaseAdapter:$latest_version"
}