Adapter Delegates

An opinionated library for working with RecyclerView's adapters.

Usage

Add dependency

Add JitPack repository:

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

Add dependency in your module (e.g. app/build.gradle):

dependencies {
    implementation 'me.italankin:adapter-delegates:1.1.0'
}

Write some code

Base components of the library are AdapterDelegate and CompositeAdapter.

You can either implement AdapterDelegate directly or use BaseAdapterDelegate as a base class for your delegates:

class TitleAdapterDelegate : BaseAdapterDelegate<TitleAdapterDelegate.ViewHolder, Title>() {

    override val layoutRes: Int = R.layout.item_title

    override fun isType(position: Int, item: Any): Boolean {
        return item is Title
    }

    override fun createViewHolder(itemView: View): ViewHolder {
        return ViewHolder(itemView)
    }

    override fun onBind(holder: ViewHolder, position: Int, item: Title) {
        holder.title.text = item.title
    }

    class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val title: TextView = itemView.findViewById(R.id.title)
    }
}

Then create an instance of CompositeAdapter and set as adapter of RecyclerView:

val adapter = CompositeAdapter.Builder<Any>(this)
    .add(TitleAdapterDelegate())
    // add more adapters if you need
    // an optional viewType can be provided:
    .add(R.layout.item_title, TitleAdapterDelegate())
    .create()

// provide a dataset for adapter
adapter.setDataset(createDataset())

// finally, set RecyclerView adapter
recyclerView.adapter = adapter

You can use CompositeAdapter.Builder methods to set dataset and attach adapter to RecyclerView:

val adapter = CompositeAdapter.Builder<Any>(this)
    .add(TitleAdapterDelegate())
    .dataset(createDataset())
    .recyclerView(recyclerView)
    .create()

Usage with DiffUtil

The library provides Diffable interface:

class Title(
    // provide unique ID for this item
    override val id: Long,
    val title: String
) : Diffable {

    override fun contentEquals(other: Diffable): Boolean {
        return other is Title && title == other.title
    }
}

val adapter = DifferCompositeAdapter.Builder<Diffable>(this)
    .add(TitleAdapterDelegate())
    .recyclerView(recyclerView)
    .setHasStableIds(true)
    .create()

// submit list to apply changes
adapter.submitDataset(createDataset())

// for any change in the dataset create a copy of it
// it is required by DiffUtil to work correctly
val newDataset = ArrayList(adapter.dataset)
newDataset.removeFirst()
adapter.submitDataset(newDataset)

License

MIT License

Copyright (c) 2022 Igor Talankin

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
furnished 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.