Add button inside Toolbar

This example modify from my old post "Implement checkable items in OptionsMenu of Toolbar" to add button to Toolbar.

Edit activity_main.xml to add Button inside android.support.v7.widget.Toolbar:

    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidtoolbar.MainActivity">

            android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="56dp"
        android:background="#FFA000">
                    android:id="@+id/toolbarbtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Button"
            android:layout_gravity="right"/>
    
            android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!" />

MainActivity.java

package com.blogspot.android_er.androidtoolbar;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    Button toolBarBtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar)findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        getSupportActionBar().setTitle("Toolbar example");
        toolbar.setSubtitle("Android-er.blogspot.com");
        toolbar.setLogo(android.R.drawable.ic_menu_info_details);

        toolBarBtn = (Button)findViewById(R.id.toolbarbtn);
        toolBarBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getBaseContext(),
                        "Button in ToolBar clicked",
                        Toast.LENGTH_LONG).show();
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        Toast.makeText(this, item.getTitle(), Toast.LENGTH_LONG).show();

        int item_id = item.getItemId();
        switch(item_id){
            case R.id.item_checkable1:
                if(item.isChecked()){
                    item.setChecked(false);
                }else{
                    item.setChecked(true);
                }
                break;
            case R.id.item_checkable2:
                if(item.isChecked()){
                    item.setChecked(false);
                }else{
                    item.setChecked(true);
                }
                break;
        }

        return super.onOptionsItemSelected(item);
    }
}