Recycler View With Android DataBinding

In I/O 2015, Google announced a data binding library for Android. With Data Binding, you create an ongoing link between an element in the user interface and a value. Data Binding is the process that establishes a connection between the Application UI and business logic.

In this post, we will learn how to integrate RecyclerView with Android Data Binding.

Step 1

Enable Data Binding in your module level gradle. Here is how your build.gradle should look.

apply plugin: 'com.android.application'
android {
compileSdkVersion 24
buildToolsVersion "23.0.3"
defaultConfig {
applicationId "com.androidgig.recyclerviewbinding"
minSdkVersion 15
targetSdkVersion 24
versionCode 1
versionName "1.0"
dataBinding {
enabled true
}
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:23.4.0'
compile 'com.android.support:recyclerview-v7:23.4.0'
compile 'com.squareup.picasso:picasso:2.5.2'
}

Step 2

Create POJO/Model class called User with 3 parameters i.e. name, profile_image & age.

public class User {
private String name, profile_image;
private int age;
public User(String name, String profile_image, int age) {
this.name = name;
this.profile_image = profile_image;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getProfile_image() {
return profile_image;
}
public void setProfile_image(String profile_image) {
this.profile_image = profile_image;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}

Step 3

Create a layout for Recycler list items

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<data>
<variable
name="user"
type="com.androidgig.recyclerviewbinding.User" />
</data>
<LinearLayout android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<LinearLayout android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:background="@drawable/round_corner_view"
android:orientation="horizontal"
android:padding="10dp">
<ImageView android:layout_width="50dp"
android:layout_height="50dp"
tools:src="@mipmap/ic_launcher"
app:url="@{user.profile_image}" />
<LinearLayout android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginLeft="10dp"
android:orientation="vertical">
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@{user.name}"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textColor="@android:color/black"
tools:text="Name" />
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@{`` + user.age}"
android:textColor="@android:color/black"
tools:text="Age" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
</layout>

Here, the user will be model class reference variable. You can have any number of variables, as you need. <layout> will contain your model class information, using which you will notify your controls about the value that they are going to show.

Step 4

Create an adapter for RecyclerView called UserAdapter.

public class UserAdapter extends RecyclerView.Adapter<UserAdapter.ViewHolder> {
private ArrayList<User> list;
public UserAdapter(ArrayList<User> list) {
this.list = list;
}
@Override
public UserAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View statusContainer = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_item, parent, false);
return new UserAdapter.ViewHolder(statusContainer);
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
User status = list.get(position);
holder.bindUser(status);
}
@Override
public int getItemCount() {
return list.size();
}
class ViewHolder extends RecyclerView.ViewHolder {
private RecyclerItemBinding binding;
public ViewHolder(View itemView) {
super(itemView);
binding = DataBindingUtil.bind(itemView);
}
public void bindUser(User user) {
binding.setUser(user);
}
}
}

Here

binding = DataBindingUtil.bind(itemView); will create binding for your recycler_item layout and return view.

binding.setUser(user); will set the user data to recycler items.

Step 5

Write XML code for your activity/fragment layout.

<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<RelativeLayout android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView android:id="@+id/recycler"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layoutManager="android.support.v7.widget.LinearLayoutManager" />
</RelativeLayout>
</layout>

Step 6

Write your code in the activity/fragment to attach adapter to RecyclerView.

public class MainActivity extends AppCompatActivity {
private ActivityMainBinding binding;
private ArrayList<User> userList = new ArrayList<>();
private UserAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
fillData();
adapter = new UserAdapter(userList);
binding.recycler.setAdapter(adapter);
}
private void fillData() {
userList.add(new User("Ravi", "https://pbs.twimg.com/profile_images/446522135721164800/pdVA44as.jpeg", 26));
userList.add(new User("Ritesh", "", 30));
userList.add(new User("Naman", "", 20));
}
@BindingAdapter({
"bind:url"
})
public static void setImage(ImageView imageView, String url) {
if (url != null & amp; & amp; url.trim().length() & gt; 0) {
Picasso.with(imageView.getContext()).load(url).error(R.mipmap.ic_launcher).into(imageView);
} else
imageView.setImageResource(R.mipmap.ic_launcher);
}
}

Output

Output

This article was originally posted on AndroidGig.com.