Android-Data Binding

The Data Binding Library is a support library that allows you to bind UI components in your layouts to data sources in your app using a declarative format rather than programmatically

1.First create a new Android project and chose empty activity and Java language.

2.Go to build.gradle file and add this under android{}:

android {
    dataBinding {
        enabled = true
    }
}

After that sync project.

Data binding in Activity

3. Go to on xml file which is default created activity_main.xml. Below is the code for the activity_main.xml file.

Here just giving an example of how to use binding for a button and what its use is.

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">
    <data>
    </data>
    <LinearLayout
        android:layout_width="match_parent"
        android:orientation="vertical"
        android:padding="16dp"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/btn_submit"
            android:text="Submit"
            android:layout_gravity="center"
            android:layout_marginTop="8dp" />

    </LinearLayout>
</layout>

4. Working on the java file, MainActivity.java file, and using the following code in it.

package com.example.databindingexample;
import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import android.os.Bundle;
import android.view.View;
import com.example.databindingexample.databinding.ActivityMainBinding;

public class MainActivity extends AppCompatActivity {
    ActivityMainBinding binding;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding= DataBindingUtil.setContentView(this,R.layout.activity_main);
        binding.btnSubmit.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                    }
                }
        );
    }
}

Data binding in Fragment

1.Go to the app right-click and create a new blank fragment as MainFragement. Use the code:

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">
    <data>
    </data>
    <LinearLayout
        android:layout_width="match_parent"
        android:orientation="vertical"
        android:gravity="center_horizontal"
        android:layout_height="match_parent"
        tools:context=".MainFragment">
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/bt_submit"
            android:text="submit"
            android:layout_marginTop="8dp" />
    </LinearLayout>
</layout>

2.Then Go to the MainFragment.java file and use the following code in it.

package com.example.databindingexample;
import android.os.Bundle;
import androidx.databinding.DataBindingUtil;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.example.databindingexample.databinding.FragmentMainBinding;

public class MainFragment extends Fragment {

    private FragmentMainBinding binding;
    private View view;

    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    public MainFragment() {
        // Required empty public constructor
    }

    // TODO: Rename and change types and number of parameters
    public static MainFragment newInstance(String param1, String param2) {
        MainFragment fragment = new MainFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        binding= DataBindingUtil.inflate(inflater,R.layout.fragment_main,container,false);
        view=binding.getRoot();

        binding.btnSubmit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
            }
        });

        return view;
    }
}