How to create a Menubar/Actionbar class instead of writing actionbar code for every class

[Jorge Vazquez]

How can I remove all the code pertaining to my Actionbar/Menubar from every activity and put it in a single class. Then instantiate that class and include it in every single one of my activities (is this possible or this code needs to be repeated in every activity?). That way I can reuse the code instead of typing the code all over again. The first thing I did was to move all code from Actionbar and create a single class. Then I instantiate the MenubarActivity class in every activity but that is not working. If someone can give me some clues how to/what is the best way to achieve this. Or what am I doing wrong on my code. Thanks MenubarActivity code:

package org.pctechtips.droidnetscan;

import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.PopupWindow;

/**
 * Created by George on 5/7/2017.
 */

public class MenuBarActivity extends AppCompatActivity {

    private Toolbar myToolbar;
    private PopupWindow popUpWindow;
    private LinearLayout linearMain;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        //referencing LinearLayout in activity_main.xml for popup window
        linearMain = (LinearLayout) findViewById(org.pctechtips.droidnetscan.R.id.linearLayout_main);
        //setting the ActionBar for the activity
        myToolbar = (Toolbar) findViewById(org.pctechtips.droidnetscan.R.id.my_toolbar);
        setSupportActionBar(myToolbar);
    }

    /*
    * Infating the menu for toolbar
    */
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(org.pctechtips.droidnetscan.R.menu.menu, menu);
        return true;
    }

    /*
    * actions for menu options in toolbar
    */
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == org.pctechtips.droidnetscan.R.id.action_ping) {
            Intent pingIntent = new Intent(this, PingActivity.class);
            startActivity(pingIntent);
            return true;
        }

        if (id == org.pctechtips.droidnetscan.R.id.action_netstat) {
            Intent netstatIntent = new Intent(this, NetstatActivity.class);
            startActivity(netstatIntent);
            return true;
        }

        if (id == org.pctechtips.droidnetscan.R.id.action_refresh) {
            //reload this activity (refresh)
            Intent thisActivity = new Intent(this, MainActivity.class);
            startActivity(thisActivity);
            return true;
        }

        if (id == org.pctechtips.droidnetscan.R.id.action_about) {
            showAboutWindow();
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    /*
    * method to display about popup window with app informmation
    * eg: developer name, version, website
    */
    public void showAboutWindow() {
        LayoutInflater layoutInflater
                = (LayoutInflater)getBaseContext()
                .getSystemService(LAYOUT_INFLATER_SERVICE);
        View popupView = layoutInflater.inflate(org.pctechtips.droidnetscan.R.layout.popup_win, null);
        popUpWindow = new PopupWindow(
                popupView,
                LinearLayout.LayoutParams.WRAP_CONTENT,
                LinearLayout.LayoutParams.WRAP_CONTENT);

        Button btnDismiss = (Button)popupView.findViewById(org.pctechtips.droidnetscan.R.id.dismiss);
        btnDismiss.setOnClickListener(new Button.OnClickListener(){
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                popUpWindow.dismiss();
            }});

        //position popup window at center of screen
        popUpWindow.showAtLocation(linearMain, Gravity.CENTER, 0, 0);
    }
}

Menu for actionbar

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <!-- Settings, should always be in the overflow -->
    <item android:id="@+id/action_ping"
        android:title="Ping"
        app:showAsAction="never"/>

    <item android:id="@+id/action_netstat"
        android:title="Netstat"
        app:showAsAction="never"/>

    <item
        android:id="@+id/action_refresh"
        android:icon="@drawable/ic_refresh_white_24dp"
        android:title="Refresh"
        app:showAsAction="always"/>

    <!-- Settings, should always be in the overflow -->
    <item android:id="@+id/action_about"
        android:title="About us"
        app:showAsAction="never"/>

</menu>

Instatiating MenuBarActivity in all activities

MenuBarActivity actionBar = new MenuBarActivity();

what is the proper way to include the MenuBarActivity in every single activity, so the actionbar gets displayed with the activity? Thanks