All posts by edwardm

Have App Inventor questions?

If you have questions about App Inventor or App Inventor programming, try posting your questions on the Facebook page “wall” and also here in the comments (I will be working to have the comments cross linked between this web site and FB eventually).

Also check out these two online forums:

Carlos has posted a good question about a problem with Bluetooth communications. If you can help, add a comment there.

 

Using TimePicker and DatePicker for entering time and date information

The TimePicker and DatePicker User Interface Controls

Entering the date and time are common features of business applications. We could use a text edit box and let the user type in times (like 10:30) or dates (12 January 2015) but both methods require the user to enter the time or date in the proper format – and the app needs to test the entered data to ensure it was entered correctly.

A better solution is to use App Inventors TimePicker and DatePicker controls. Both provide a graphical method of selecting input values. For example, the TimePicker displays the following:

TimeDate_TimePickerUIThe time is set by pressing the + or – buttons above and below the hours and minutes. The AM/PM indicator is a toggle – when it shows PM, a press changes it to AM, and when it shows AM, a press changes it to PM. With this input system, the user can never entered an invalid time (the user could, of course, enter the wrong time, but that is a different problem!)

Continue reading Using TimePicker and DatePicker for entering time and date information

Raspberry Pi 2 (US $35) computer board features Scratch

Raspberry Pi 2 is a US$ 35 computer board to which you attach a monitor, keyboard, mouse and Ethernet connection. You can use the Pi 2 for web browsing and other functions, but it also comes with Scratch.

Scratch is a programming system that is very similar to MIT App Inventor. You can learn more about Scratch in our previous post on that topic!

But because one of Raspberry Pi’s goals is to advance computer science education, there’s a few pieces of bundled software that can help achieve that goal. This includes a drag-and-drop visual programming language called Scratch (great for beginners to create animations and games), as well as Sonic Pi (for creating electronic music) and more advanced programming languages like Python (also included).

via Surf Report: Taking a bite out of Raspberry Pi.

And speaking of STEM, here are some videos from yesterday’s Oregon City FRC FIRST Robotics Pacific Northwest District 2 (Oregon) robotics competition. 35 high school robotic teams took part, with Team #4488 “Shockwave” taking first by total points. I am biased: I am a volunteer engineering mentor with the Shockwave team, from Glencoe High School, Hillsboro, Oregon. Go Shockwave!

Continue reading Raspberry Pi 2 (US $35) computer board features Scratch

Motion picture highlights high school robotics

Press Release – January 14, 2015 | USFIRST.org.
New Movie Starring Jamie Lee Curtis, George Lopez, Carlos PenaVega, and Marisa Tomei Highlights FIRST® Students’ Famous Underdog Robotic Victory against MIT

‘Spare Parts’ Debuts in Theaters Nationwide on January 16 Featuring Robots Built by FIRST Teams.

Watch the Spare Parts movie trailer on Youtube here.

FIRST Robotics is not App Inventor, but FIRST is a high visibility showcase of youth STEM programs. Since 2008, I have been a volunteer engineering mentor with high school FIRST Robotics teams. The 2015 FIRST robotics competition season is underway now.

To learn more about FIRST Robotics in your area, or to start a team, visit USFIRST.ORG.

The team where I volunteer (Shockwave Team #4488!!!!!) has implemented several Android apps using MIT App Inventor. One of their apps, a robotic-themed game based on the 2015 competition, is available in the Google Play store as a free download. Other apps are used by the team during competition to collect data on other teams, which is then analyzed in an Excel spreadsheet (written using Visual Basic for Applications code) to develop optimal competitive game strategies.

(Sorry for no new App Inventor code examples this week – had an ear infection for a few days that caused dizziness. Everything is okay now!)

Blockly – the code editor that drives App Inventor

Blockly is the block code editor used in App Inventor. Blockly provides a way to write programs by arranging blocks of code, rather than writing out traditional “source code” text programs.

This approach is helpful for new programmers who can focus on the programming – and not the details of the structure of the programming language (of which there are many in programming languages like Java, C/C++, and C#).

Continue reading Blockly – the code editor that drives App Inventor