Tag Archives: programming

Android Development, Tips

Using droid-at-screen to see your phone’s display on your computer

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droid-at-screen is a free Java-based app that displays the content of your phone’s display to your computer’s display, when the phone is connected via a USB cable.

Below is a screen snap shot taken from my computer display. At the upper left is the Droid@Screen application running.  Droid@Screen is connected to my Nexus 5 phone.

At right is the display showing on my phone, which has been transferred from the phone to my computer over a USB connection. I’ve circled two user interface items – the magnifying glass icon is used to adjust the display size of the phone’s screen. Since the phone has a 1920×1080 display, the initial image is quite large!

Below that is a camera icon. Click on that to take a snapshot of what is on the screen, and then save the screen image to a local file.

Capture

At the lower left is the DroidAtScreen .jar file. This is the Java executable program file. Assuming Java is installed on your system, double click the .jar file to begin running Droid@Screen.

Continue reading Using droid-at-screen to see your phone’s display on your computer →

Components, Programming Method, STEM Education

A “switch board” user interface panel for App Inventor apps

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In the last post, we introduced some concepts for building “creative” App Inventor user interfaces that feature visually appealing user interface controls rather than the usual bland buttons.

In this post, we look at creating an array of toggle switches. Tapping a switch flips the switch from left to right, or right to left.

Concepts

In developing this user interface, we learn two concepts:

  1. We expand on the previous post and its use of images to create custom buttons.
  2. We see how a user interface control can be stored in a list and referenced like a variable within our apps.

Source code:

The User Interface

I called my app “Mission Control” because any good mission control panel needs lots of switches!

The user interface features 9 toggle switches in a 3 x 3 array. The purpose of this app is to demonstrate how to implement this type of interface – the app does not otherwise do anything interesting.

Tapping any toggle switch causes the switch lever to move to the other side of the switch. Here is a screen shot showing some toggle switches to the left and some to the right.

Screenshot_20160204-140323The Designer View

Continue reading A “switch board” user interface panel for App Inventor apps →

General, Programming Method, Software, STEM Education

Writing Android apps in Javascript

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Another way to develop apps for Android is to write apps in the Javascript program scripting language (note – Javascript is not related to Java, in spite of the similar name). By using a special platform called Cordova, it is possible to package Javascript programs into a self contained Android .apk file that runs on the Android OS.

Even better – it is possible to package your Javascript app, using Cordova, into forms that run on iOS (iPhones and iPad) and Windows Phone too!

Continue reading Writing Android apps in Javascript →

Components, Software

MIT App Inventor “Extensions”

Some new “extension” features are available for testing in App Inventor at MIT App Inventor Extensions. The 4 extensions include vector addition, simple image processing, simple audio processing to identify the pitch of a sound, and the addition of multi-touch gestures to the Canvas.

I have not yet had time to try these but this is a sign of things to come as 3rd parties can begin to develop extensions to the core set of App Inventor features.

Look forward to trying these out! Click on the link above to take a look.

Components, Documentation, Programming Method, Software, STEM Education

Free-Download App Inventor Location Sensor Cheat Sheet

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Download here: App Inventor Location Sensor Cheat Sheet (PDF)

High res, suitable for printing. Feel free to share with others.

App Inventor sample source code: Location_WhereAmI.aia

Here is a GIF image but use the PDF for printing – also, where it says “enter a mailing address”, that should probably be “enter a street address”!

Voila_Capture 2015-10-28_12-21-17_PM

Post comments here or on our Facebook group page. Thank you!

E-Books and Printed Books

If you find these tutorials helpful (I hope you do!) please take a look at my books on App Inventor. To learn more about the books and where to get them (they are inexpensive) please see my App Inventor Books page.

  • App Inventor 2 Introduction (Volume 1 e-book)
    Step-by-step guide to easy Android programming
  • App Inventor 2 Advanced Concepts (Volume 2 e-book)
    Step-by-step guide to Advanced features including TinyDB
  • App Inventor 2 Databases and Files (Volume 3 e-book)
    Step-by-step TinyDB, TinyWebDB, Fusion Tables and Files
  • App Inventor 2 Graphics, Animation and Charts (Volume 4 e-book and printed book)
    Step-by-step guide to graphics, animation and charts

Thank you for visiting! — Ed

Documentation, Programming Method, Software, STEM Education

All new tutorial: Using TinyDB in App Inventor

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I have completely rewritten and re-done my original tutorial on using TinyDB in App Inventor.

You can see the all new rewrite at Using TinyDB in App Inventor

TinyDB is a database used to store and retrieve values to semi-permanent storage on your phone or tablet. Unlike variables, which vanish when your app closes or your phone is turned off, values stored in the TinyDB are retained and can be accessed again, much later.

The original post was a popular post here on the blog, but it was brief and left out some details. I started over from scratch and wrote an all new, complete tutorial, with screen shots and blocks code, and downloadable App Inventor source code. Hope this helps!

E-Books and Printed Books

If you find these tutorials helpful (I hope you do!) please take a look at my books on App Inventor. To learn more about the books and where to get them (they are inexpensive) please see my App Inventor Books page.

  • App Inventor 2 Introduction (Volume 1 e-book)
    Step-by-step guide to easy Android programming
  • App Inventor 2 Advanced Concepts (Volume 2 e-book)
    Step-by-step guide to Advanced features including TinyDB
    • App Inventor 2 Databases and Files (Volume 3 e-book)
      Step-by-step TinyDB, TinyWebDB, Fusion Tables and Files
      Buy from: Amazon, Google Books, Kobo Books
  • App Inventor 2 Graphics, Animation and Charts (Volume 4 e-book and printed book)
    Step-by-step guide to graphics, animation and charts

Thank you for visiting! — Ed