Although App Inventor is sometime described as an educational toy that you can use to get kids interested in programming don't let this fool you into thinking that you can't do real things with it. It makes a very good prototyping facility - as we discover here.

App Inventor is an amazing way to create Android applications. You don't need to be able to program but if you can then all the better.

All I can say is that as a programmer this is the first time in quite a while that a development environment and its associated "language" has brought a smile to my face. It's not perfect, it's still in beta, but if you give it a little room to grown on you might just smile as well.

Although App Inventor is sometime described as an educational toy that you can use to get kids interested in programming don't let this fool you into thinking that you can't do real things with it. It makes a very good prototyping facility and a couple of the prototypes that I have created have actually ended up as final apps that are still in use.

Getting started

The worst part of trying any new programming environment is having to download and install things.

For the App Inventor this is less of a problem because a lot of it is designed as a web application. To use it you need a Google account - if you don't have one it is worth signing up.

However some of the system does run on your local machine - the Android emulator and the  designer. These are both Java applications and so your first task is to make sure that you have an up-to-date Java 6 (also known as 1.6) installation. You can check by clicking on the following link: Java test page.

After checking that you have Java installed you need to download the installer appropriate for your operating system - Windows, Linux or MacOS X. I used the Windows version.

• Instructions for Mac OS X
• Instructions for GNU/Linux
• Instructions for Windows

Once the installation is complete you are ready to start using the App Inventor.

If you have had an older version of App Inventor installed on your computer it is a good idea to install the most recent version.

Don't worry at this stage about things like a USB driver for your phone or tablet the simulator is the best way to get started and there are other ways to get  your app onto your real phone without a USB driver.

To get started go to

http://beta.appinventor.mit.edu

If you are already signed in to Google you will be able to go straight to MyProjects - if not sign in and click MyProjects. The MyProjects section saves all of the apps you create for further use.

When you are learning a new system there is a lot to be said for the simpler the better. So lets create a Hello World app.

Hello World

Move to My Projects and click the New button. Enter HelloWorld and click the OK button. After a few moments you should see the App Inventor Designer window open. Anything you create using the App Inventor under the project named HelloWorld will be saved under your account for you to use the next time you log in.

Before getting started you need to know that the Designer, as its name suggest is used to design and create the user interface of your application.

If you have used a drag-and-drop designer for any other programming language this will be nothing new to you apart perhaps from the fact that it is hosted on the web.

Notice that the designer doesn't provide any behavior for the user interface you create  - this is all done using the Blocks Editor which is the second member of the team.

So to sum up:

• the Designer is used to create the User Interface

and

• the Blocks Editor is used to create the logic of the program, i.e. what the app does.

We will come to the Blocks Editor in a moment. For now let's just design a simple UI - in fact the simplest UI that can be made to do something.

The Designer

The Designer is split into four regions -

• the Palette where you pick the components you want to use to build the UI. The Palette is divided into sections according to the type of component. For our example we only need to explore the Basic tab.
• the Viewer which represents the screen of the phone and is used to layout the components of the UI
• the Components pane which shows you a different view of the components that you have placed on the viewer - why you need a different view will become all too clear later on.
• the Properties pane which lists all of the settings for the currently selected component. You use this to customize each component.

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