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

    <!--text view for displaying referer details-->
    <TextView
        android:id="@+id/idTVRefrer"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:layout_margin="3dp"
        android:gravity="center_horizontal"
        android:padding="4dp"
        android:text="Refrer"
        android:textAlignment="center"
        android:textColor="@color/purple_200"
        android:textSize="18sp" />

</RelativeLayout>

import android.os.Bundle;
import android.os.RemoteException;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import com.android.installreferrer.api.InstallReferrerClient;
import com.android.installreferrer.api.InstallReferrerStateListener;
import com.android.installreferrer.api.ReferrerDetails;

public class MainActivity extends AppCompatActivity {

    // creating variables for text view.
    private TextView refrerTV;

    // variable for install referer client.
    InstallReferrerClient referrerClient;

    // creating an empty string for our referer.
    String refrer = "";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // initializing all our variables.
        refrerTV = findViewById(R.id.idTVRefrer);

        // on below line we are building our install referrer client and building it.
        referrerClient = InstallReferrerClient.newBuilder(this).build();

        // on below line we are starting its connection.
        referrerClient.startConnection(new InstallReferrerStateListener() {
            @Override
            public void onInstallReferrerSetupFinished(int responseCode) {
                // this method is called when install referer setup is finished.
                switch (responseCode) {
                    // we are using switch case to check the response.
                    case InstallReferrerClient.InstallReferrerResponse.OK:
                        // this case is called when the status is OK and
                        ReferrerDetails response = null;
                        try {
                            // on below line we are getting referrer details
                            // by calling get install referrer.
                            response = referrerClient.getInstallReferrer();

                            // on below line we are getting referrer url.
                            String referrerUrl = response.getInstallReferrer();

                            // on below line we are getting referrer click time.
                            long referrerClickTime = response.getReferrerClickTimestampSeconds();

                            // on below line we are getting app install time
                            long appInstallTime = response.getInstallBeginTimestampSeconds();

                            // on below line we are getting our time when 
                            // user has used our apps instant experience.
                            boolean instantExperienceLaunched = response.getGooglePlayInstantParam();

                            // on below line we are getting our
                            // apps install referrer.
                            refrer = response.getInstallReferrer();

                            // on below line we are setting all detail to our text view.
                            refrerTV.setText("Referrer is : \n" + referrerUrl + "\n" + "Referrer Click Time is : " + referrerClickTime + "\nApp Install Time : " + appInstallTime);
                        } catch (RemoteException e) {
                            // handling error case.
                            e.printStackTrace();
                        }
                        break;
                    case InstallReferrerClient.InstallReferrerResponse.FEATURE_NOT_SUPPORTED:
                        // API not available on the current Play Store app.
                        Toast.makeText(MainActivity.this, "Feature not supported..", Toast.LENGTH_SHORT).show();
                        break;
                    case InstallReferrerClient.InstallReferrerResponse.SERVICE_UNAVAILABLE:
                        // Connection couldn't be established.
                        Toast.makeText(MainActivity.this, "Fail to establish connection", Toast.LENGTH_SHORT).show();
                        break;
                }
            }

            @Override
            public void onInstallReferrerServiceDisconnected() {
                // Try to restart the connection on the next request to
                // Google Play by calling the startConnection() method.
                Toast.makeText(MainActivity.this, "Service disconnected..", Toast.LENGTH_SHORT).show();
            }
        });
    }
}