Monthly Archives: September 2017

Android Development, Tips

Can you create an MIT App Inventor app without a computer? YES

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Several people have asked me if it is possible to create an Android app without using a computer. Yes, it is possible!

All you need do is access appinventor.mit.edu in the web browser on your Android device. App Inventor works the same as it does on a computer.

You’ll need to go in to Android Settings | Security and check the option to allow installation of apps from Unknown Sources.

Then, in the App Inventor web interface, you will use Build | App (save .apk to my computer). The app will be “compiled” (translated into an executable program file for Android known as an “apk” file – short for Android package) and then downloaded to your computer.

The download part will vary depending on what browser you are using as well as what version of Android you have. You might find the download icon (a down arrow) in the notification bar. Swype down from the top and then select the downloaded file, open it and select Install to install your app. Once installed, you can run the app directly – or the app will appear in the list of apps installed on your device and you can run it directly from the app list. The exact way this all happens will vary depending on your system and browser.

The following video tutorial shows I how I did this on Android using the Opera browser. Note that I used a Bluetooth keyboard and a Bluetooth mouse – so the screen looks like I am using a computer because I am not touching anything!

 

App Inventor News

MIT App Inventor team receives Distinguished Leadership Award from the Mass Technology Leadership Council

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The MIT App Inventor team accepted the Council’s Distinguished Leadership Award for working to make application development universally accessible.

Source: Wayfair CEO Niraj Shah, athenahealth, and Toast Take Top Honors at 20th Annual Mass Technology Leadership Awards

Congratulations to the team! Well done! Well deserved!

Appy Builder, Components

Appy Builder: Using the BatteryStatus component #AppInventor #AppyBuilder #STEM #Programming

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A reader asked if there is a way to determine the status of the Android device battery in MIT App Inventor. Unfortunately, App Inventor does not provide a way to check the battery status … but Appy Builder does!

To answer that question, our first Appy Builder app is a simple tutorial showing how to use the BatteryStatus component in Appy Builder.

User Interface

The output is displayed after pressing the Start button and shows that my phone’s battery is at 99% and was plugged in to the AC power charger.

In this screen shot, the phone was unplugged from the battery charger and the “plugged in” status has changed to UNKNOWN.

Designer View

I created this screen by adding a Button control, and then adding six HorizontalLayouts. Inside each layout, I dragged two Label controls, setting one to the descriptive text (such as “Battery level:” and the second to be used to display the status for that property).

Blocks View

The BatteryManager has several properties that describe aspects of the battery.

Before the properties may be used you must activate the BatteryManager by setting the .StartMonitoring property to true; this must be done separately as shown below. Errors occurred when I put that code inside the button’s .Click handler. Instead, I moved the StartMonitoring assignment to the Screen1.Initialize event handler and everything worked fine.

  • BatteryLevel – the battery’s current level in percent
  • BatteryTemperature – the temperature of the battery in degrees Celsius
  • BatteryPresent – true (my phone does not permit me to remove the battery)
  • BatteryPlugged – returns “AC” if the device is connected to a charger, or UNKNOWN if the device is not plugged in. This might also return “WIRELESS” if the device is currently using a wireless charger (based on Android BatteryManager API).
  • BatteryVoltage – battery voltage. A typically value will be near 4 volts plus or minus for most phones.
  • BatteryHealth – GOOD. I presume this returns a value corresponding to the Android BatteryManager API, which includes COLD, DEAD, GOOD, OVERHEAT, OVER_VOLTAGE, UNKNOWN and UNSPECIFIED_FAILURE.

Download Source

Right-click (or Ctrl-click on Mac OS X) and use your browser’s feature to save this file to your computer: BatteryStatus.aia

Then, use Projects | Import selected project (.aia) from my computer … to load the file into Appy Builder