Write and sell Android apps with Basic 4 Android: Part 1

Now you’re ready to try compiling and running the sample program. Hit the blue “Run” icon on the toolbar (or select Compile & Run from the Project menu).

The first time you do this you’ll be prompted to provide a filename, and then a Package Name – a unique identifier for your app, which is structured as a sort of backwards URL, such as uk.co.pcpro.ourfirstapp. It isn’t necessary to actually register this as a real subdomain; the idea is simply to come up with an identifier that’s guaranteed not to clash with an existing one. For more details, see Oracle’s official documentation on package names.

Finally you’ll be asked for an application label – the name that will appear below the app’s icon in the Android app menu.

The program should now compile, and B4A will try to install it to a connected Android device, so make sure your AVD is up and running. You can also test on an actual smartphone or tablet if you enable Debugging mode on the device – see the B4A documentation for more information about this.

If all is well, you should see the message box appear on the screen of your AVD. Click on it and it will close. Congratulations! You’ve compiled and run your first Android app. Next time you run it, all of the settings you just entered will be remembered, so it will compile and run straight away. If you want to change the package name or application label, you’ll find the options under the Project menu.

Note that Android apps don’t shut down automatically (unless you write code to make them do so), so if you’re running in Debug mode you’ll have to stop execution by clicking the green Stop button in the debug panel at the bottom of the IDE (see Debug mode, below).

If you’re using the full version of B4A, the process is much the same, except that the first time you open the IDE you’ll be prompted to register. One user is permitted to run B4A across two computers, but be warned that the licence file is deleted after registration, so keep a copy of it somewhere safe.

You’ll also notice that the full version of B4A opens with an empty program framework. If you want to test that everything is working as above, add a single line of code so that lines 14-16 of the framework read as follows:

As you type, your code is automatically colour-coded and capitalised to help you follow what’s going on. Once you’ve entered this single line, you can compile and run the program, and click on the message box (you’ll see the second string, “Information”, is its title) to see that everything is working as it should.

The structure of a B4A program

As we’ve mentioned, B4A is very similar to VB. Programs don’t proceed linearly from the first line to the last; instead, they’re event driven. You build up an app by creating standalone sections of code to handle specific events, such as when a particular button is pressed. These sections of code are called “subs”, just as they are in VB.

The framework that opens when you first open B4A is pre-populated with several subs. The one containing the code that makes the message box appear is called “Activity_Create” (don’t worry about the part in brackets for the moment). “Activity” is Android jargon, referring to the application’s full-screen graphical interface. The suffix “_Create” specifies that this sub is triggered when the activity first appears. In other words, code placed here will execute automatically when the program runs.

You can write your own subs to handle other events. As an example, let’s write some code to place a button onscreen, and a sub that will be called when it’s clicked. We’ll start by editing Activity_Create so it reads as follows:

B4A uses familiar object-oriented syntax, with objects having methods and properties that can be accessed by appending their names to the object name. As you’ll have noticed as you typed in the above code, when you type a dot, a dropdown menu appears showing valid keywords; when you type an open bracket, you get a helpful pop-up reminder of the required syntax.

Read more: Write and sell Android apps with Basic 4 Android: Part 1 | Analysis | Features | PC Pro http://www.pcpro.co.uk/features/380845/write-and-sell-android-apps-with-basic-4-android-part-1/2#ixzz2SMPxmtvz

Write and sell Android apps with Basic 4 Android:

Android apps are big business, but the native development tools aren’t exactly beginner-friendly. There’s a laundry list of technical concepts you need to master before you can write even a simple “Hello world!” program. You also have to learn to work with Eclipse, an open source development environment with plenty of quirks. Happily, you don’t have to use native tools. Absolute beginners can assemble their own programs in a visual environment using the free MIT App Inventor service. And for those seeking a more hands-on approach, it’s possible to create, share and publish apps using a friendly Basic-type language, without having to deal with the more abstruse aspects of native Java development. Basic options One free option is RFO Basic for Android, an open source programming environment that’s free to download from Google Play. It’s modelled on “classic” Dartmouth Basic, so it’s very easy to get up and running.

However, since the package runs entirely on your smartphone or tablet, you don’t get the conveniences of a Windows-based development environment – nor, with most devices, a physical keyboard. We’ve therefore chosen to focus instead on Basic for Android (or B4A for short), a Windows-based package that’s modelled on Visual Basic (VB). It isn’t quite as simple as RFO Basic, but it’s much easier than diving straight into Eclipse and Java – and much closer to the native Android way of doing things, giving you a leg-up if you choose to graduate to native programming later on.

Unlike RFO Basic, Basic for Android is a commercial product. A free 30-day trial is available from the developers’ website, and this is all you’ll need to follow this month’s introduction to the language. However, the trial doesn’t support external modules and libraries, so to create more advanced apps, you’ll need a full licence. This costs $49 (around £30) and includes two months of updates, as well as entitling you to post questions and download code snippets from the B4A forums. Options are also offered for longer update periods and multiple developers.

In this feature, and in the accompanying second part, we’ll get you started with the language and the development environment, after which you can go on to build more advanced programs with the aid of the official documentation and user forums – and we’ll even show you how to publish and sell your creations on Google Play. Setting up Android Basic for Android runs within Windows, but Android programs won’t work on your desktop – they must be tested on an Android device.

The trial version of B4A includes a feature called “remote compilation”, which beams your code to a mobile phone or tablet for testing. At present, though, this works only for simple programs and isn’t in the full version of B4A. A more flexible way to test your code is to compile it locally and run it in an Android Virtual Device (AVD) – an emulator, in other words. This is slower than using a real device, but it lets you test your code at any resolution. To set this up, you’ll need to install the Java Development Kit and the Android SDK; our walkthrough shows you how.

Compiling your first Android program Once you’ve installed Java and the Android SDK, and created your AVD for testing, it’s time to configure Basic for Android. If you’re using the trial version of B4A, the IDE opens containing a placeholder program, which simply pops up a message box. We can run this program to test everything is working – but first we need to direct B4A to the resources it needs for compiling Android apps. To do this, check that Remote Compilation Mode is unticked under the Tools menu, then select Tools | Configure Paths.

You’ll be prompted to provide paths to the needed Java and Android components. If you’re using 64-bit Windows, look in the Program Files (x86) folder rather than the main Program Files folder as suggested. Leave “Additional libraries” blank for now. Read more: Write and sell Android apps with Basic 4 Android: Part 1 | Analysis | Features | PC Pro http://www.pcpro.co.uk/features/380845/write-and-sell-android-apps-with-basic-4-android-part-1#ixzz2SMF9CUdI