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Write your first Java GUI app

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Here is a quick guide that shows how you can create and compile your first Java app with Net Beans.

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I have a number of guides on moving hasting away form CPanel, Setting up VM’s on AWS, Vultr or Digital Ocean along with installing and managing WordPress from the command line. Updating the serves is a pain so I am writing a java app for Windows and OSX to help me manage the server by telnetting in on port 22 and performing routine actions from a button click in Java.

Installing Java and NetBeans IDE

Goto https://netbeans.org/downloads/index.html and click “JDK with NetBeans IDE Java SE bundle”

Download Net Beans

Download Netbeans and Java SE bundle

Download

Install Netbeans and Java SE bundle

Installed

Creating your first GUI Java Application

Create  New Project (Java Application) in NetBeans, Click Next

New Project

Name the project and set the main class as “main”

New Project

Add a new file, a “Swing GUI Form/JFrame form“.

Add Form

Name the J Frame Form and click Finish.

J Frame Form

Adding GUI elements in NetBeans IDE

In the Net Beans IDE, you can simply drag and drop elements.  I like to move my properties screen to the bottom centre.

GUI Designer

Set the panel at the default startup element

Add the following code to the main.java file

> framemain form = new framemain();
> form.setVisible(true);

Show Form

Compile the App

The app compiles 🙂

App Compiles

Add an action to a button

You can add button actions (events) in the design mode.

Add Button Event

Add Hello World alert box code to the button

Add the following to the Panel code file

> public static void infoBox(String infoMessage, String titleBar)
> {
>     JOptionPane.showMessageDialog(null, infoMessage, “InfoBox: ” + titleBar, JOptionPane.INFORMATION_MESSAGE);
> }

Add this to the action (event)

System.out.println(“Hello World”);
> frame1.infoBox(“Hello World”, “Hello World”);

 

Build

To build right-click on the project and click Clean and Build

java-build

The result is an app you can run by double-clicking the jar file.

Java Hello World Alert Box

I hope this helps someone.

Making an OSX APP file from the JAR file

Coming soon

Making a Windows EXE file from the JAR file

Coming soon

 

I hope this guide helps someone.

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Revision History

v1.0 Initial post

Building your first app on Heroku

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Below is my blog post on setting up a hello world app on Heroku that is powered by a database (e.g Client requests a page, the page reads a database and return hello world).

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I found IBM/Cloudant would cost multiple thousands a month to run a good NoSQL database backend, I moved to a self-managed server on Digital Ocean in Singapore but the distance of the server killed latency and maximum throughput in Australia.  I moved to a dedicated AWS EC2 instance with a  Mongo DB cluster on AWS in Australia and it was great but pricey. A self-managed server (on Digital Ocean or Vultr) allows you to install whatever you want (e.g PHP, MySQL, MongoDB, Redis, SSL Certificate, Mail or WordPress) and configure what you want (but at what cost?).

Heroku say: “Get straight to building apps – Setting up, operating and maintaining your own platform is not where the race is won. Avoid the risk and complexity, and dedicate your energy to what really matters: building great apps.”.

heroku

Having setup serves on IBM Cloudant, Digital Ocean, AWS and Vultr (and even managing with RunCoud and Webmin) and not focusing on a self-managed server-issues like security, backup, security audits, upgrading PHP, updating ssl, setting up distributed mysql, updating https certificates etc sounds like the holy grail.

Let’s put that to the tets and build a Hello World App.

About Heroku

Heroku have a page here about what they offer.

Heroku

Sign up for Free: https://signup.heroku.com

Signup

Programming Languages (Ruby, PHP, Python, NodeJS, Java, Cloujure, Scala, Go etc). I so wanted to select “I’m not a developer” but I won’t.  I selected NodeJS.

Programming Language

Next: Verify your email, enter a password and you’ll find yourself here.

Setup Done

Now we can create an app?

App Help

Help

Ok, let’s skim the NodeJS help before we start: https://devcenter.heroku.com/articles/getting-started-with-nodejs#set-up

Let’s download the Command Line tools

Heroku CLI

Installing Heroku CLI on OSX was uneventful

Heroku CLI

 

I clicked the “I have installed the Heroku CLI” button.

Heroku wanted me to clone a repo but I logged in to Heroku the Heroku CLI and created a local Heroku folder first (in my local Terminal).

I checked the Heroku Version

I checked Heroku Help

I ran the advised commands

At this point, I followed the steps at https://devcenter.heroku.com/articles/getting-started-with-nodejs#deploy-the-app

Ran

The website is up

App Up

Where is this app located

Traceroute times out but appears to be in the eastern United States (AWS).

Q1) Can I change to Sydney Australia?

Twitter

Waiting for an answer from Twitter.

Virginia is a long way away.

Let’s test the SSL

It’s all good apart from on weak cipher (“TLS_RSA_WITH_3DES_EDE_CBC_SHA (0xa) WEAK (112)“).

SSL

A shodan scan of the IP reveals an open port 80 and 443 (as expected, nothing out of the ordinary)

Pushing Changes

I ran this to push the app.

I ran this to ensure the app was running

I ran this to open the app

This opened the apps URL in a browser.

A nice help page was pushed to my app.

I changed the contents of “node-js-getting-started/views/pages/index.ejs” and repushed.

It reported “Everything up-to-date“???

Repush

I tried to force a push (just in-case something on the server was changed)

???

Ok, let’s pull and see what’s new?

I edited “./index.js” and made the entry point “pages/index2.ejs” and tried to push and no luck.

I tried running push under sudo too (no luck)

Googling revealed I can go to https://dashboard.heroku.com/apps/YOUR-APP/deploy/heroku-gi and see what the issue is.

I logged into the app and could not find how to delete or edit it?

How do I edit files

At this point, I would have just ssh’ed in and restarted the node process in pm2 or node on my own self-managed server and edited remote files locally in sublime on my local machine.

Personally, I like to know where files live and not delve into another designers management interface.

I’ll come back to this guide later until then I’ll stick with Digital Ocean or Vultr

Linking to your own Domain on Heroku

It looks like I can use custom domains via Namecheap to link a domain to a heroku app. 

Or you can setup a domain sub domain to point to a heroku app with a DNS C Name record. 

Database Setup

Todo.. 

Node talking to the database. 

Todo.. 

App Cost on Heroku

todo: After Hello World is deployed. Digital Ocean (is as low as $5 a month) or Vultr (is as low as $2.5 a month)

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Revision History

v1.4 added custom domain, database, CNAME info

etc

Installing Android Studio 3 and creating your first Kotlin Android App

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Below is my quick post showing how you can create your own Hello World Android app using the new Kotlin language on OSX. More will be added to this blog post over time.

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What is Kotlin

Kotlin is a statically-typed programming language that runs on Java Virtual Machines (the syntax is not compatible with Java but interoperates with it).  Kotlin is Google’s default language for deveAndroid Android Apps.Kotlin is now the offimoremorecial language supported by Google for Android development. Kotlin v JAVA: http://androiddeveloper.galileo.edu/2017/10/16/kotlin-vs-java-what-is-the-difference/

The official Kotlin language page can be found here: https://kotlinlang.org/ (Wikipedia has a page here).

Kotlin has a “Try Kotlin” page here ( https://try.kotlinlang.org/ ) where you can the language out in a browser.  Android Studio 3 is the latest IDE from Google that allows you to develop apps in JAVA pr Kotlin for Android.

Learn Kotkin: Hello World Demo

Hello Wprls Demo

Kotlin Hello World Code:

fyi: Other Kotlin Code Examples:

Kotlin Language Reference: http://kotlinlang.org/docs/reference/

Tutorials: http://kotlinlang.org/docs/tutorials/

Books: http://kotlinlang.org/docs/books.html

More Resources: http://kotlinlang.org/docs/resources.html


Installing Android Studio on OSX

You will need to install the latest Android Studio 3 IDE from the link below.  This will allow you to download the latest Android SDK, Android Emulator, tools and Documentation from Google.

Download Android Studio from here: https://developer.android.com/studio/index.html?utm_source=android-studio

You should now have a 750MB (or there about’s) file (called something like android-studio-ide-171.4408382-mac.dmg )

You are now ready to run the setup dmg and install the app.

Kotlin Downloaded

“Replace” Earlier Versions (if you had 1.x or 2.x installed)

Replace Android Studio

You may be asked to choose the default Android emulator ram size

Emulator Ram Size

Congratulations, Android Studio 3 should now be installed

Installed

Congratulations you now have the Android Studio 3 IDE Installed.

Android Studio Tips and Tricks: https://medium.com/@mmbialas/50-android-studio-tips-tricks-resources-you-should-be-familiar-with-as-an-android-developer-af86e7cf56d2

Android Studio 3 User Guide: https://developer.android.com/studio/intro/index.html

Official getting started guide: https://developer.android.com/training/basics/firstapp/index.html

Setting Android Studio Defaults

Don’t forget to download updates and set auto updates “to enabled” in the Android Studio preferences screen.

Android Studio Auto Updates

Goto the “SDK Manager” menu item under the “Tools” then “Android” menu.

SDK Manager

You can Download additional Android SDK versions, updates and emulator environments.  I would recommend you pre-download the Android 3.x to 8.x environments.

ADK API Versions

You can also download and create Emulated Android Devices in the Android Virtual Device (AVD) Manager menu.

Andoiud Emulator

You can choose an existing Android Device (emulated)

Choose Emulated Device

Create Your Own Virtual Device

You can also create your own Android virtual device (Emulated) for testing.

I have a physical Huawei Mate 9 device (for physical testing), I will set up a similar virtual device (but stick with 2GB ram instead of 4GB as my development Mac only has 8GB total ram).

AVD Create

You can choose an emulators device skin if you so desire. Many phone skins can be found online (e.g here, here and here). Samsung Developer page has a skins page here. Managing AVD user guide here: https://developer.android.com/studio/run/managing-avds.html. I don’t use emulator device skins as this uses much-needed memory and screen real estate.

When you are done configuring your virtual device image you may be prompted to download missing images (e.g  in my case I need to download API 27/ Android 7.1.1).

Download

Physical Device Setup (Enable Developer Mode)

You should always code on physical devices where possible (emulators are ok but have a handful of physical devices on hand to test on).  I find the emulator crashes a lot on me.

How to enable developer mode on a physical Android device: https://developer.android.com/studio/debug/dev-options.html.  When you have enabled developer mode you can enable advanced developer options (I like these options).

Dev Options

When you have a physical Android device setup and connected, you can choose to run the app on the physical device.

Run on device

Creating Your first Hello World Kotlin Project

By now you will have Android Studio 3 installed, Configured Updates, Configured an Emulator device and hopefully a real test device. Now you can open Android Studio and select.

1. “Start a New Android Studio Project”
2. Name your project (e.g “My Kotlin Test App 001”)
3. Ensure your company name is unique (e.g “com.fearby.testgithub001android”
4. Tick “Include Kotlin Support” (not ticked by default).

New Project

5. Click “Next“.
6.You will need to choose the minimum API and Android version to support. If you choose a new API you may limit the potential users that can run your app and if choose an old API you will limit the potential features.  In my case, I will choose 7.0 for my test project (but will choose 4.1 in public apps).  Click “Help me choose” to see the percentage of users and features in each API version.

Version

7. Clik “Next”

8. Choose “Empty Activity” and click “Next“.

9. Take note of Activity name of “MainActivity” and Layout Name of “activity_main” and click “Finish“.

Now that you have a new project you can start Emulatorkator (Tools, Android, AVD Manager then press Play next to your emulator of choice).

Emulator

 

10. Now click Run and choose the Emulator to start.

Run

 

Before we add a button to the test app, let’s add a Anko dependency to the project ( https://github.com/Kotlin/anko ) to make coding easier.

11. Open your “app/Gradle Scripts/build.gradle (Module: app)” node in the Android Project treeview.

12. View add the following line to the dependencies section (refer to https://github.com/Kotlin/anko and replace “0.10.2” with the version listed at thGitHubub site). Then click “Sync Now”.

Anko

13. Goto “app/res/layout/activity_main.xml” (1) and add a button to the layout (2) and name the button (3)

Add Button

14. Goto “app/java/%projectname%/MainActivity” (1) and add the following two lines  (2)(3) below.

Add the following at the top of “MainActivity”

Add the following in the “onCreate” function (ensure your button name is the same as you called it).

Wire up Button

15. You can now build and deploy the app to a device (or emulator, real devices are faster).

RunA

Add a Button to change activity screens

The official documentation on changing activity screens can be found here.

1. Rename the button from above from”Button” to ‘Hello World”
2. Add a new button can call it “buttonnextscreen” (set constraints if you wish to match the hello world button left and width).

Next Screen Button

3. Now you can add and a new target activity screen ( e.g Open your project in the treeview (1), select “New” (2), select “Activity” (3) and then choose the activity type you want (e.g “Empty Activity” (2) ).

New Activity Screen
4. Name the “Activity Name” and “Layout Name” and click “Next“.

More info on Kotlin fragments: https://www.raywenderlich.com/169885/android-fragments-tutorial-introduction-2

5. In “MainActivity.kx” I edited the following (time to use Anko Intents and not just Anko toast )

I also wired up the new “Next Activity” Button

Now you have wired up a button to change Activity Screens.  The Android back button will fire the previous screen so there is no need to wire up a  returning button (like on iOS).

Next Activity

This is the Next Activity screen that was called from a button (exciting eh).

Set and Read Textbox

After adding a textbox and button this is how I set and red text in a textbox control.

Create, Set and Read Local Class

I added a button (ID) called “buttoncreateclass” and setup a “setOnClickListener” (in onCreate) to create a class, fill it then output the data from the class to three textboxes (“textfirstname”, “textsurname” and “textage”)

Adding Application Icons.

Read the official guidelines here: https://developer.android.com/studio/write/image-asset-studio.html

I use the free cions generator here: https://romannurik.github.io/AndroidAssetStudio/

Ensure you replace the following files (with your project closed)..

  • res/mipmap-hdpi/ic_launcher_round.png (72 x 72 px)
  • res/mipmap-hdpi/ic_launcher.png (72 x 72 px)
  • res/mipmap-hdpi/ic_launcher_round.png (72 x 72 px)
  • res/mipmap-hdpi/ic_launcher.png (72 x 72 px)
  • res/mipmap-xhdpi/ic_launcher_round.png (96 x 96 px)
  • res/mipmap-xhdpi/ic_launcher.png (96 x 96 px)
  • res/mipmap-xxhdpi/ic_launcher_round.png (144 x 144 px)
  • res/mipmap-xxhdpi/ic_launcher.png (144 x 144 px)
  • res/mipmap-xxxhdpi/ic_launcher_round.png (192 x 192 px)
  • res/mipmap-xxxhdpi/ic_launcher.png (192 x 192 px)

You may also need to remove the res/drawable XML files to prevents the automatically genrated im,ages from loading.

  • DELETE: “res/drawable/ic_launcher_background.xls”
  • DELETE: “res/drawable/ic_launcher_foreground.xls”

You may need to force a delete (Right Click then “Delete” then “OK” then “Delete Anyway“).

Force Delete

I had a number of errors related to removing references to the automatically generated images.

File “anydpi-v26/ic_launcher.xml” and “anydpi-v26/ic_launcher_round.xml” had this contents.

I replaced the contents of the file “anydpi-v26/ic_launcher.xml” and “anydpi-v26/ic_launcher_round.xml” with

 

Then you will need to click the “Build” menu then “Clean Project” to remove references to the files.

“Build“, “Clean” results.

Now you can build an APK with static icons (yes, that’s my face).

Icons

 

Read move on “realtime generated/adaptive” v “image” icons here: https://medium.com/@ianhlake/vectordrawable-adaptive-icons-3fed3d3205b5

Official guide on Adaptive Icons: https://developer.android.com/guide/practices/ui_guidelines/icon_design_adaptive.html

Displaying Alerts

Displaying a hard-coded option with Anko

Displaying a list with options with Anko

Making Phone Calls, Sending Text, Browing the web and sending Emails

Anko has some cool helper methods to allow you to send and share content.

As long as you add the appropriate buttons, text fields you can add these button listeners.

Layout

Email

Background Async Calls

You can call background calls and then invoke the UI thread when the call has returned.

App Manifest Permissions

Edit the file “app/src/mainAndroidManifest.xml” and add the following two lines above the “<applications” node

View all permission options here: https://developer.android.com/reference/android/Manifest.permission.html

By default your app will not ask for permissions (unless you set them).

Permissions

Downloading data from the Internet (API Endpoint)

Add the following to a button to make a anetwork call.

Example Result:

More soon.

Adding soon: Network (submit data).

Adding soon: Plan Sound.

Adding soon: Animations.

Adding soon: String Encryption.

Adding soon: Basic Security.

 

 

 

Updating your Android Studio IDE (do this often)

Don’t forget to download updates (and enable auto updates) in the Android Studio IDE.  At the start of this draft blog post, I installed Android Studio 3.0 (Four hours later a large 1.3 GB sized update was available), I had to download many smaller updates too.

AS Updates

This is a frequent update that would not go away for me.

Update Gradle

Copying the app to an Android Device.

Once you have enabled debug mode you can copy apps to and from the physical device.  You can build an APK by going to the “Build” then “Build APK’s” menu and build the file to your project folder (e.g “/Users/simon/AndroidStudioProjects/MyKotlinTestApp001/app/build/outputs/apk/debug/app-debug.apk“). You can then copy this file to your Android device (via the Android File Transfer app) and you can now run the app anytime you want away from your Mac.

File Transfer

Also before you copy and unsigned apps to your test device tyoiu will need to enable developer mode then enable the running of apps from “unknown sources“.

Unknown Sources

If you have any security apps instaled like Sophos you will be told that yiour app has a low rating.

Low Reputation

 

APK living on your device 🙂

Device

The Android Studio also has a real device debugger.

Android Device Monitor

Monitor output from a show stats from a real device

Debug

 

Android Security 101 (you need to know this)

You can define network configuration per these instructions: https://developer.android.com/training/articles/security-config.html

Coming from developing iOS and desktop apps I decided on researching the current state of Android Security. I would strongly suggest you watch this video from Marcos Placona ( https://twitter.com/marcos_placona Developer Evangelist @ Twilio).

Takeaway’s from this video

My Suggestions

  • Secure your Ubuntu server (info here and here).
  • Use an HTTPS SSL Certificate
  • Use Certificate Pinning
  • Ask for app token/keys from your server and keep in memory.
  • Use OAuth 2 to secure sessions
  • Use short timeouts (or expire on use) on tokens with sensitive data.
  • Call upstream objects form API to prevents client-side attacks.

Deploying your app to the Android/Google Play store

To publish an app to the Google Play store you will need to create a Google Play Developer Account, pay $25 USD and you are free to publish an app on the Google Play store. Read more here: https://play.google.com/apps/publish/

Publishing an app is as simple as filling in the blanks in the publish app screen.

Store

Troubleshooting

  • You will need a  fast system with at least 8MB of ram (16GB is ideal).
  • Apple XCode users will find Android Studio 3 slow and unstable (so backup your project often).
  • Building apps take a long time so be prepared to wait for build and deploys to devices.
  • Update warnings are aplenty, get used to them.

Read More

Kotlin Community: http://kotlinlang.org/community/

Android Studio ~ Android Central Blog: https://www.androidcentral.com/tag/android-studio

Huawei Developer Page: http://developer.huawei.com/en/

Samsung tips on using Android Studio: http://developer.samsung.com/galaxy/emulator-skin/guide#tips

Create a custom emulator skin https://developer.android.com/studio/run/managing-avds.html#skins

Follow Android Dev on Twitter: https://www.twitter.com/AndroidDev

Read: https://androidsecurity.info/

An Introduction to Kotlin: https://code.tutsplus.com/tutorials/an-introduction-to-kotlin–cms-24051

Reddit: https://www.reddit.com/r/androiddev/

Create Non XML based layouts (with ANKO):

Kotlin v JAVA: http://androiddeveloper.galileo.edu/2017/10/16/kotlin-vs-java-what-is-the-difference/

Read more about Android Studio 3: http://www.technoblogpost.com/android-studio-3-0/

Jetbrains Android Studio Guidelines: https://www.jetbrains.com/help/idea/2016.2/general-guidelines.html

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v1.57 added Async calls, app icon, misc screenshots, Anko alert, email, sms, share code, permissions, network download etc.