Android Studio – Menu buttons not showing up on toolbar in Android app creating through androidstudio

Iam creating an app where users can add items using the add item button which is in recycler view but I also want to add menu buttons which should display on the toolbar…

Problem
The menu buttons are not getting displayed on the tool bar. In design preview of menu_main.xml the buttons are being displayed properly.

But when running this app on device the menu buttons are not being displayed.

ActivityMain code: (In this I have created onCreateOptionsMenu method at the bottom)

package com.example.foodmanagement;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.ItemTouchHelper;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
//import androidx.appcompat.widget.Toolbar;
import android.app.Activity;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.Toast;
import android.widget.Toolbar;

public class MainActivity extends AppCompatActivity {

    Toolbar mToolbar;
    Button mBtnAdd;
    BucketRecyclerView mRecycler;
    Realm mRealm;
    RealmResults<Drop> mResults;
    View mEmptyView ;
    AdapterDrops mAdapter;

    private View.OnClickListener mBtnAddListener = (v) -> {
            showDialogAdd();
    };

    private AddListener mAddListener = new AddListener() {
        @Override
        public void add() {
            showDialogAdd();
        }
    };

    private RealmChangeListener mChangeListener = new RealmChangeListener() {
        @Override
        public void onChange(Object o) {
            Log.d(TAG, "onChange: was called");
            mAdapter.update(mResults);
        }
    };

    private MarkListener mMarkListener = new MarkListener() {
        @Override
        public void onMark(int position) {
            showDialogMarkFinish(position);
        }
    };

    private CompleteListener mCompleteListener = new CompleteListener() {
        @Override
        public void onComplete(int position) {
            mAdapter.markComplete(position);
        }
    };

    private void showDialogAdd() {
        DialogAdd dialog = new DialogAdd();
        dialog.show(getSupportFragmentManager(),"Add");
    }

    private void showDialogMarkFinish(int position) {
        DialogMarkFinish dialog = new DialogMarkFinish();
        Bundle bundle = new Bundle();
        bundle.putInt("POSITION", position);
        dialog.setArguments(bundle);
        dialog.setCompleteistener(mCompleteListener);
        dialog.show(getSupportFragmentManager(), "Mark");
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activitymain);
        mRealm = Realm.getDefaultInstance();
        mResults = mRealm.where(Drop.class).findAllAsync();
        mToolbar =  findViewById(R.id.toolbar);
        mEmptyView = findViewById(R.id.empty_drops);
        mRecycler = (BucketRecyclerView) findViewById(R.id.rv_drops);
        mRecycler.addItemDecoration(new Divider(this, LinearLayoutManager.VERTICAL));
        mRecycler.hideIfEmpty(mToolbar);
        mRecycler.showIfEmpty(mEmptyView);
        LinearLayoutManager manager = new LinearLayoutManager(this);
        mRecycler.setLayoutManager(manager);
        mAdapter = new AdapterDrops(this,mRealm, mResults, mAddListener, mMarkListener);
        mRecycler.setAdapter(mAdapter);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            setActionBar(mToolbar);
        }
        mBtnAdd = (Button) findViewById(R.id.btn_addd);
        mBtnAdd.setOnClickListener(mBtnAddListener);
        SimpleTouchCallback callback = new SimpleTouchCallback(mAdapter);
        ItemTouchHelper helper = new ItemTouchHelper(callback);
        helper.attachToRecyclerView(mRecycler);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater=getMenuInflater ();
        inflater.inflate ( R.menu.menu_main,menu );
        return true;
    }

    @Override
    protected void onStart() {
        super.onStart();
        mResults.addChangeListener(mChangeListener);
    }

    @Override
    protected void onStop() {
        super.onStop();
        mResults.removeChangeListener(mChangeListener);
    }
}

Menu_main.xml code

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item
    android:id="@+id/action_add"
    android:icon="@drawable/ic_action_add"
    android:title="Add"
    app:showAsAction="always" />
    <item
        android:id="@+id/action_sort_descending_date"
        android:title="Most Time Left" />
    <item
        android:id="@+id/action_sort_ascending_date"
        android:title="Least Time Left" />
    <item
        android:id="@+id/action_show_complete"
        android:title="Finished" />
    <item
        android:id="@+id/action_show_incomplete"
        android:title="Remaining" />
</menu>

v21/toolbar.xml

    <?xml version="1.0" encoding="utf-8"?>
<Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="@color/dark_blue">
</Toolbar>

layout/toolbar.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="@dimen/abc_action_bar_default_height_material"
    android:background="@android:color/white">
</androidx.appcompat.widget.Toolbar>

values/theme.xml

<resources xmlns:tools="http://schemas.android.com/tools">
    <!-- Base application theme. -->
    <style name="Theme.FoodManagement" parent="Theme.MaterialComponents.DayNight.NoActionBar.Bridge">
        <!-- Primary brand color. -->
        <item name="colorPrimary">@color/purple_500</item>
        <item name="colorPrimaryVariant">@color/purple_700</item>
        <item name="colorOnPrimary">@color/white</item>
        <!-- Secondary brand color. -->
        <item name="colorSecondary">@color/teal_200</item>
        <item name="colorSecondaryVariant">@color/teal_700</item>
        <item name="colorOnSecondary">@color/black</item>
        <!-- Status bar color. -->
        <item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
        <!-- Customize your theme here. -->
    </style>
</resources>

night/theme.xml

<resources xmlns:tools="http://schemas.android.com/tools">
    <!-- Base application theme. -->
    <style name="Theme.FoodManagement" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Primary brand color. -->
        <item name="colorPrimary">@color/purple_200</item>
        <item name="colorPrimaryVariant">@color/purple_700</item>
        <item name="colorOnPrimary">@color/black</item>
        <!-- Secondary brand color. -->
        <item name="colorSecondary">@color/teal_200</item>
        <item name="colorSecondaryVariant">@color/teal_200</item>
        <item name="colorOnSecondary">@color/black</item>
        <!-- Status bar color. -->
        <item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
        <!-- Customize your theme here. -->
    </style>
</resources>