In this tutorial, you’ll learn how to create an audio recording app using the smartphone’s microphone. Read on!
Tutorial Teaser
Step 1: Application Overview
Using pre-made graphics we will code a recording application with Lua and the Corona SDK.
The user will be able to record, play and replay the selected audio.
Step 2: Target Device
The first thing we have to do is select the platform we want to run our app within. That way we’ll be able to choose the size for the images we will use.
The iOS platform has these characteristics:
- iPad 1/2: 1024x768px, 132 ppi
- iPad 3: 2048×1536, 264 ppi
- iPhone/iPod Touch: 320x480px, 163 ppi
- iPhone 4/iPod Touch: 960x640px, 326 ppi
- iPhone 5/iPod Touch: 1136×640, 326 ppi
Because Android is an open platform, there are many different devices and resolutions. A few of the more common screen characteristics are:
- Asus Nexus 7 Tablet: 800x1280px, 216 ppi
- Motorola Droid X: 854x480px, 228 ppi
- Samsung Galaxy SIII: 720x1280px, 306 ppi
In this tutorial we’ll be focusing on the iOS platform with the graphic design, specifically developing for distribution to an iPhone/iPod touch, but the code presented here should apply to Android development with the Corona SDK as well.
Step 3: Interface
A simple and friendly interface will be used with a background and multiple buttons.
The interface graphic resources necessary for this tutorial can be found in the attached download.
Step 4: Export Graphics
Depending on the device you have selected, you may need to export the graphics in the recommended ppi, you can do that in your favorite image editor.
I used the Adjust Size… function in the Preview app on Mac OS X.
Remember to give the images a descriptive name and to save them in your project folder.
Step 5: App Configuration
An external file will be used to make the application go fullscreen across devices, the config.lua file. This file shows the original screen size and the method used to scale that content in case the app is run in a different screen resolution.
application =
{
content =
{
width = 320,
height = 480,
scale = "letterbox"
},
}
Step 6: Main.lua
Let’s write the application!
Open your prefered Lua editor (any Text Editor will work, but you won’t have syntax highlighting) and prepare to write your awesome app. Remember to save the file as main.lua in your project folder.
Step 7: Code Structure
We’ll structure our code as if it were a Class. If you know ActionScript or Java, you should find the structure familiar.
Necessary Classes
Variables and Constants
Declare Functions
contructor (Main function)
class methods (other functions)
call Main function
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