MainActivity.java

package com.mahc.custombottomsheet;

import androidx.annotation.NonNull;
import androidx.coordinatorlayout.widget.CoordinatorLayout;
import androidx.viewpager.widget.ViewPager;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import androidx.appcompat.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.widget.TextView;

import com.mahc.custombottomsheetbehavior.BottomSheetBehaviorGoogleMapsLike;
import com.mahc.custombottomsheetbehavior.MergedAppBarLayout;
import com.mahc.custombottomsheetbehavior.MergedAppBarLayoutBehavior;


public class MainActivity extends AppCompatActivity {

    int[] mDrawables = {
            R.drawable.cheese_3,
            R.drawable.cheese_3,
            R.drawable.cheese_3,
            R.drawable.cheese_3,
            R.drawable.cheese_3,
            R.drawable.cheese_3
    };

    TextView bottomSheetTextView;

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

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        ActionBar actionBar = getSupportActionBar();
        if (actionBar != null) {
            actionBar.setDisplayHomeAsUpEnabled(true);
            actionBar.setTitle(" ");
        }

        /**
         * If we want to listen for states callback
         */
        CoordinatorLayout coordinatorLayout = (CoordinatorLayout) findViewById(R.id.coordinatorlayout);
        View bottomSheet = coordinatorLayout.findViewById(R.id.bottom_sheet);
        final BottomSheetBehaviorGoogleMapsLike behavior = BottomSheetBehaviorGoogleMapsLike.from(bottomSheet);
        behavior.addBottomSheetCallback(new BottomSheetBehaviorGoogleMapsLike.BottomSheetCallback() {
            @Override
            public void onStateChanged(@NonNull View bottomSheet, int newState) {
                switch (newState) {
                    case BottomSheetBehaviorGoogleMapsLike.STATE_COLLAPSED:
                        Log.d("bottomsheet-", "STATE_COLLAPSED");
                        break;
                    case BottomSheetBehaviorGoogleMapsLike.STATE_DRAGGING:
                        Log.d("bottomsheet-", "STATE_DRAGGING");
                        break;
                    case BottomSheetBehaviorGoogleMapsLike.STATE_EXPANDED:
                        Log.d("bottomsheet-", "STATE_EXPANDED");
                        break;
                    case BottomSheetBehaviorGoogleMapsLike.STATE_ANCHOR_POINT:
                        Log.d("bottomsheet-", "STATE_ANCHOR_POINT");
                        break;
                    case BottomSheetBehaviorGoogleMapsLike.STATE_HIDDEN:
                        Log.d("bottomsheet-", "STATE_HIDDEN");
                        break;
                    default:
                        Log.d("bottomsheet-", "STATE_SETTLING");
                        break;
                }
            }

            @Override
            public void onSlide(@NonNull View bottomSheet, float slideOffset) {
            }
        });

        MergedAppBarLayout mergedAppBarLayout = findViewById(R.id.mergedappbarlayout);
        MergedAppBarLayoutBehavior mergedAppBarLayoutBehavior = MergedAppBarLayoutBehavior.from(mergedAppBarLayout);
        mergedAppBarLayoutBehavior.setToolbarTitle("Title Dummy");
        mergedAppBarLayoutBehavior.setNavigationOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                behavior.setState(BottomSheetBehaviorGoogleMapsLike.STATE_ANCHOR_POINT);
            }
        });

        bottomSheetTextView = (TextView) bottomSheet.findViewById(R.id.bottom_sheet_title);
        ItemPagerAdapter adapter = new ItemPagerAdapter(this,mDrawables);
        ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
        viewPager.setAdapter(adapter);

        behavior.setState(BottomSheetBehaviorGoogleMapsLike.STATE_ANCHOR_POINT);
        //behavior.setCollapsible(false);
    }
}