<?xml version="1.0" encoding="utf-8"?>
<!--we are using coordinator layout for this example-->
<androidx.coordinatorlayout.widget.CoordinatorLayout 
    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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <!--button to expand the view-->
    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|start"
        android:layout_margin="16dp"
        android:text="Click to Expand"
        app:layout_dodgeInsetEdges="bottom" />

    <!--Nested scroll view to display 
        bottom scrolled layout-->
    <androidx.core.widget.NestedScrollView
        android:id="@+id/bottom_sheet"
        android:layout_width="match_parent"
        android:layout_height="350dp"
        android:background="@color/purple_500"
        app:behavior_hideable="true"
        app:behavior_peekHeight="0dp"
        app:layout_behavior="@string/bottom_sheet_behavior"
        app:layout_insetEdge="bottom">

        <!--we will be displaying a simple text
            view in that nested scroll view-->
        <TextView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:padding="16dp"
            android:text="Welcome to the DSA Self paced Course,
                          where you will get to learn all about 
                          Data Structures and Algorithms in detail."
            android:textColor="@color/white"
            android:textSize="16sp"
            android:textStyle="bold" />
    </androidx.core.widget.NestedScrollView>
</androidx.coordinatorlayout.widget.CoordinatorLayout>

import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import androidx.appcompat.app.AppCompatActivity;

import com.google.android.material.bottomsheet.BottomSheetBehavior;

public class MainActivity extends AppCompatActivity {

    // creating a new variable for bottom sheet behaviour.
    private BottomSheetBehavior bottomSheetBehavior;

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

        // initializing view for our bottom sheet below.
        View bottomSheet = findViewById(R.id.bottom_sheet);

        // initializing bottom sheet behaviour
        // with our bottom sheet view.
        bottomSheetBehavior = BottomSheetBehavior.from(bottomSheet);

        // initializing the button where we will
        // be displaying our expanded view.
        Button button = findViewById(R.id.button);

        //adding on click listener to our button.
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // below line is use to expand our view on button click in android.
                bottomSheetBehavior.setState(BottomSheetBehavior.STATE_EXPANDED);
            }
        });
    }
}