Bindapter

You will never build an adapter again

Bindapter use the power of DataBinding to build a flexible RecyclerView.Adapter which will save you a lot of time.

Bindapter is totally built with Kotlin + Love 💖.

Usage

Only create your view using databinding

<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <variable
            name="item"
            type="com.example.app.Item"/>
    </data>

   <TextView
        android:id="@+id/img"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@{item.title}"/>
</layout>

Then create your Bindapter

val adapter = Bindapter<ItemModel>(R.layout.item_view, BR.item)

And then set it to your RecyclerView

recyclerView.adapter = adapter

As simple as that, now you can spend your time on more important things

Setup

1. Active DataBinding in your project build.gradle

android {
    dataBinding {
        enabled true
    }
}

1.1 If you are using Kotlin - Configure Databinding Compiler with Kapt

apply plugin: 'kotlin-kapt'

dependencies {
  kapt 'com.android.databinding:compiler:3.0.1'
}

2. Configure maven url in your root build.gradle This one is temporal 😄

allProjects {
    repositories {
        maven { url  "http://dl.bintray.com/silmood/bindapter" }
    }
}

3. Import Bindapter

Gradle 3.X.X

implementation 'com.silmood.bindapter:bindapter:0.1.1'

Gradle 2.X.X

compile 'com.silmood.bindapter:bindapter:0.1.1'

Listening Events

If you want to add interaction in your views you just have to add a Handler (or whatever you like name it) class when you create a Bindapter:

Kotlin

class Handler {
    fun onClick(view: View) { ... }
    fun onClickImage(view: View, item: ItemModel) { ... }
}

val bindapter = Bindapter<ItemModel>(R.layout.item,
                    itemVariableId = BR.item,
                    handler = Handler(),
                    handlerId = BR.handler)

Java

public class Handler {
    public void onClick(View view) { ... }
    public void onClickImage(View view, ItemModel item) { ... }
}

Bindapter<ItemModel> bindapter = new Bindapter<>(R.layout.item, 
                                        BR.item, 
                                        new Handler(), 
                                        BR.handler);

This way you can use it in your layout.

<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <variable
            name="item"
            type="com.example.app.Item"/>
        <variable 
            name="handler" 
            type="com.example.app.Handler"/>
    </data>

   <ImageView
        android:id="@+id/img"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="@{handler::onClick}"
        app:imgUrl="@{item.image}"/>
</layout>

If you need to receive the model when an item is clicked, you can implement it this way:

   <ImageView
        android:id="@+id/img"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="@{(view) -> handler.onClickImage(view, item)}"
        app:imgUrl="@{item.image}"/>

More info about here

Binding Adapters

A binding adapter is a way to define custom behaviors to set properties in a view. For example, load images with Glide/Picasso or set TextView's color according to a model property. More info

Kotlin

The sample app contains a file named BindingAdapters.kt. This is the way you have to define them; just creating Kotlin file an put the functions there.

@BindingAdapter("imgUrl")
fun loadImage(imageView: ImageView, url: String) {
    Glide.with(imageView.context)
            .load(url)
            .into(imageView)
}

@BindingAdapter("ratingColor")
fun ratingColor(textView: TextView, ratingPercent: String) {
    val percantage = ratingPercent.toInt()
    val context = textView.context

    val color = when {
        percantage > 95 -> ContextCompat.getColor(context, R.color.positive_1)
        percantage > 90 -> ContextCompat.getColor(context, R.color.positive_2)
        else -> ContextCompat.getColor(context, R.color.negative)
    }

    textView.setTextColor(color)
}

Java

If you are using Java you just have to define your binding adapters as static methods.

@BindingAdapter({"bind:imgUrl"})
public static void loadImage(ImageView view, String url) {
   Picasso.with(view.getContext()).load(url).into(view);
}

Once it is declared you can use it in your layout:

   <ImageView
        android:id="@+id/img"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:imgUrl="@{item.image}"/>

FAQ

• My BR. class/variables are missing ¿What can i do?

The BR class isn't correctly generated yet. After define your layout you have to build again your project

• There is a problem building the project: 'Internal compiler error'

It's possible you have commit a mistake in your layout file defining types with Data Binding. Check your gradle console to know where exactly is the problem.

Code Style

This project is written on Kotlin and uses ktlint. If you find that one of your pull reviews does not pass the CI server check due to a code style conflict, you can easily fix it by running: ./gradlew :bindapter:ktlintFormat, or running IntelliJ/Android Studio's code formatter.

TODO

• Support multiple view types for different models
• Support multiple view types for the same model