Mobile App Development with Corona: Getting started – Hello World


Things you need:

Corona SDK (http://www.CoronaLabs.com),
iPhone SDK (http://developer.apple.com/ipad/sdk/) (if you want to publish to an iPad or iPhone)
And an editor (I’m using Xcode, but you could also use BBEdit, Eclipse with LuaEclipse, TextMate, Notepad or Corona Project Manager).

You don’t have to own any of this, you can easily get started with the trial version of Corona SDK and the trial version of the iPhone SDK.

Hello World
Ready to do your first program? Typically this is done as “Hello World”.
Open your editor of choice (I’m using Xcode in my demonstration).

Create a folder (or project) and then a file named ‘main.lua’ (after creating a project, click File > New > and select Other)
Type:
print (“Hello World”)

and save your file.

Now, open the Corona Terminal (make sure it is the terminal, not the simulator, or you won’t see your program run).
In the dialog box, go to your FOLDER that contains the main.lua file and click ‘open’.
You will see the iPhone simulator.. ignore it for right now. Everything happens in the terminal for this first app.
In your terminal window, you should see your “Hello World”. Congratulations! You’ve made your first Corona on the iPhone app!

Not impressed? That’s because the print function that we used to display “Hello World” is used to display information to a log file or terminal.
Okay, let’s make something happen on the simulator!

Back in Xcode (you can use the same file),
Type:
local textobj = display.newText(“Hello World”, 50, 50, nil, 24)
textobj:setTextColor(255, 255, 255)

What did you just do? Here’s the run down:
First we created a local variable called textobj. We set textobj = to the object that we create by calling display.newText, passing it the text (“Hello World”), the X & Y location of the top left corner of the text, nil (a parameter reserved for future use), and 24 (the size of the text to be created).
Second, we set the color of the textobj that was just created using the R, G, B color system (each color (red, green, blue) having a value between 0 – 255). We set the color to white.
By default, the text object has no color, so you have to assign it a color for it to be seen. You COULD create text (and you might want to in a future app) that has no color, but for now, it doesn’t serve any purpose.
Try the app out!
Now you have made your first REAL Corona app!

Video Demonstration:
[tubepress video=”GmS82aHW9zc”]

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