In this tutorial we are going to cover some advanced database code as well as tie in to some more advanced GUI techniques. We left off on the last tutorial showing you how to insert and select data to/from the database as well as make a table. What we need now is to be able to delete data if it is not needed and update it if we entered it incorrectly. We will tie these abilities in with some more advanced functionality utilizing a long press on the screen for delete and for updating we will just press the data we want to edit.
In this tutorial we will be pivoting from our last tutorial on Graphical Elements to start focusing on databases in Android development. The android platform uses SQLite databases in its applications and is one of five data storage options in android development. We will only be focusing on SQLite development in android because it is key to the construction of a workable/functional program. After this tutorial you should be able to implement a SQLite database that you are then able to insert and select items from tables in the database.
For this project we will be creating a Random Quote generator that has you enter quotes or sayings in a textbox and press a button to insert them into the database. We will issue a confirmation toast that allows us to see if the data was entered into the database successfully and the textbox will be blank. If a second button is pressed, the database will be accessed and told to select a random quote from the database to show in a toast on the screen.
Finally we see a hack that is focuses on safety when it comes to high-power laser hacks. A safety switch has been added to the butt of the flashlight body which houses the laser diode. When the safety is flipped on an LED blinks to prompt the user for a security code. If you enter the correct code on a momentary push switch, electrical access to the laser is enabled. There are also a couple of nice features such as continuous on and auto shutoff.
This would be hard to implement if you’re working on a watertight package but we like the fact that an unsuspecting house guest won’t go blind if searching for a flashlight during a storm. One last thing, the code entry system is PIC based which reminds us of [Alan Parekh’s] one-button system.
The PhorsePOV by [Julian Skidmore] almost slipped by, but we thought it was a nice easy hack for your Memorial Monday. The gadget uses an ATTINY25 to drive 6 LEDs aren’t standard characters 7 units high? Which when waved in the air produces a readable message. What we were really interested in is the use of a single button for text entry, called Phorse code, or an “easier to learn and remember” version of Morse code. While it seemed silly at first, most of us here could enter messages within a few minutes of trying.
In case you missed it back in June, the Palm Pre was rooted by extracting the Root ROM from a Palm tool used to reset a device with damaged software. A lot has been learned from examining the code inside that ROM but we’re most amused by one thing in particular. If you grew up in the 80’s there’s a pretty good chance you know the Konami Code by heart. So did the developers of WebOS, the firmware running on the Palm Pre. By inputting the familiar (UpUpDownDownLeftRightLeftRightBA) set of gestures the handset enters Developer mode for connection to the SDK which was leaked last summer but is now in open release.
openSCAD uses a language somewhat reminiscent of C for creating models. A preview of the model is rendered alongside your code. Fully cross-platform, it runs on Linux, OS X, and Windows. Much like SketchUp, openSCAD can also extrude 2D outlines into models. This feature comes in very useful if one already has a set of technical drawings for a part. With no price tag, it’s pretty affordable during this costly season.
Have you heard the latest track by gzip? Maybe it’ll end up on a “Greatest Hits” album alongside Philip Glass.
Visualization techniques such as animated algorithms can help programmers better grasp the abstract theories that make software work. Could auralization, the sound equivalent of visualization, provide similar insights? Postgrad student (and J. S. Bach fan) [Cessu] developed a program to do just that. By carefully mapping registers to notes, and slowing the tempo to a human timescale, the result is a cacophonous machine that offers a glimpse into the operation of various programs. You might find the resulting minimalist “music” insightful, entertaining…or maybe just incredibly grating.