Hey, I wrote an app and got it published on the App Store! It’s free and it only does one thing: it lets you slide a selector back and forth and show the equivalent temperature readings in Fahrenheit and Celsius. So, if that’s a thing that you want on your phone, go check it out!
So, I took this class on iOS development with Swift, because I’m fed up with Flutter and I really like being able to program the devices I own. I got to the end of the course and was thinking, “Okay, so that all makes sense, now, what do I even want to make my phone do?” And then I thought, “You know what toy application everyone wants you to write after Hello World? A unit converter.”
The problem I have with these unit converter examples, though, is that while they’re great for giving you an example of how to use list selection tools (what unit do you want to convert from/to) and detecting user input (when do you actually compute the conversion) and update the display, they’re terrible if you actually want to get the conversion value. I mean, I’m sitting in a car and the temperature is set in Celsius, and I know it’s too hot, but what is the right temperature? This is a problem with numeric displays; unless the number is on a scale that I’ve internalized, it doesn’t really mean anything to me. Also, I don’t want to have to spend a whole lot of time typing or, for that matter, waiting for my phone to ask Google’s server on the other side of the planet. This is a straightforward calculation that could be done right here, right now, with an actual thermometer if it had the scales printed on each side.
So, I present you with a dead simple app. It’s got a slider that you drag back and forth. It shows a Fahrenheit temperature and a Celsius temperature. It’s got buttons on the interface to let you step up and down if you want to go slower. And, because I wanted to learn how to make an app for the Apple Watch, there’s one of those, too, and it uses the digital crown to do scrolling up and down of the temperature.