How to create an Android App using Google’s App Inventor

August 4th, 2010 by

Today we’re going to take a look at Google’s App Inventor feature that offers programming-novices a nice possibility to enter the fabulous world of Android App programming without deeper knowledge of the API or complex SDK installations.

So lets build some stuff ..

Prerequisites

What we are going to build

  • We are building a simple GUI with a Textbox and a button
  • A click on the button starts an event that queries the acceleration sensor for coordinates
  • If the sensor is active and enabled then the coordinates are displayed in the text box

Project and GUI

  • Log into the App Inventor homepage and create a new project – I named this one “testproject
  • We want the textbox and the button to be arranged side-by-side so we’re using a Horizontal Arrangement – click on Screen Arrangement and drag Horizonzal Arrangement to the Android screen
  • Now click on Basic and drag a TextBox and a Button onto the Horizontal Arrangement
  • We’re going to need the acceleration sensor so click on Sensors and drag a Accelerometer Sensor onto the screen
  • That is all we need for now in our GUI so save your project – we are going to add some logic now ..
  • That’s what my screen looks like

Control Logic

  • The Android Blocks editor is started via Java Web Start – simply click on “Open the Blocks Editor” and run the application
  • In the first step we want to handle a click event on the button so click on My Blocks, click on YourButtonName and select the “when Button.Click do” Element
  • Before we do anything with the accelerometer sensor we want to test if the sensor is available, so click on Built-In > Controls and drag the “if test then-do” Element to the first element we have created
  • Now to add the if-condition goto My Blocks > AccelerometerSensorName and drag the AccelerometerSensor.Available Element to the preceding test node
  • Now we’re going to define the action that takes place if the button is clicked and the sensor is available – to get some coordinates and display them in the text box – at first drag the My Blocks > TextBoxName > TextBox.Text element onto the if-then element
  • We want to create a string that displays the coordinates like this example: “x: 134.44 y: -44.54 z: 22.36” so we’re going to need string functions which can be found under Build-In > Text – select the “make text” element here and drag it onto the preceding element
  • Select from the text functions a text element, click on its label, change it to “x: ” and drag the element to the first position of the make text element
  • Go to My Blocks > AccelerometerSensorName and drag the AccelerometerSensor.XAccel element to the second position of the make text element
  • Repeat the last two steps for the y and z-coordinates and return to the App Inventor Website – do not close the block editor yet because the next step requires a running instance..
  • Here is a screenshot of my result

Deploy and run

  • There are three possibilities to deploy your application: To generate a QR code to download the app in your smartphone, to download the generated apk-file in your browser or to directly install the application via USB.
  • If your usb connection works with the App Inventor you’ll probably want to use this possibility
  • Now run your application and enjoy :D

Conclusion

Google’s App Inventor enables you to create simple applications in a short time without deeper knowledge of the Android API so perhaps this creates an entry point for interested app developers. On the other side there are only a few features of the rich Android API supported yet but of course – it’s a beta version. I still hope that Google is going to put some of this work back into the SDK and especially into the “GUI builder” for my Eclipse IDE ;)

If you want to see how this application is achieved using the SDK .. take a look at the article Sensor Fun: Using the accelerometer on Android

Resources

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3 Responses to “How to create an Android App using Google’s App Inventor”

  1. Phrake Says:

    Hi, thanks for this post. It gives me something to hang on to, me being absolutely no programmer at all. I’ve been playing around with App Inventor and I must say that the programming logic is mostly lost to me. Maybe you can help me with one specific action: I want to play a sound only when the phone is tilted to the left or right and then returned into it’s original position (somewhat). Can and will you help me with this? Either way thanks!

  2. Jack Says:

    Hi… I can’t find:

    the “when Button.Click do” Element

    Can you please tell me what I missed or am doing wrong? Thank you.

  3. micha kops Says:

    Appinventor’s interface has changed a bit inbetween .. first you need to have a button placed somewhere in your GUI (using Appinventor in your browser). Now when your loading the block editor and click on “My Blocks” you should see your button .. if you haven’t given it a name then the button is named Button .. e.g. Button1
    When you click on the button you should see the “When Button1 Click Then” element.

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