Working with URL Schemes
The URL scheme is an interesting feature provided by the iOS SDK that allows developers to launch system apps and third-party apps through URLs. For example, let's say your app displays a phone number, and you want to make a call whenever a user taps that number. You can use a specific URL scheme to launch the built-in phone app and dial the number automatically. Similarly, you can use another URL scheme to launch the Message app for sending an SMS. Additionally, you can create a custom URL scheme for your own app so that other applications can launch your app via a URL. You'll see what I mean in a minute.
As usual, we will build an app to demonstrate the use of URL schemes. We will reuse the QR code reader app that was built in the previous chapter. If you haven't read the previous chapter, go back and read it before continuing on.
So far, the demo app is capable of decoding a QR code and displaying the decoded message on screen. In this chapter, we'll make it even better. When the QR code is decoded, the app will launch the corresponding app based on the type of the URL.
To start with, first download the QRCodeReader app (only available for paid customers). If you compile and run the app, you'll have a simple QR code reader app. Note that the app only works on a real iOS device.
To continue reading and access the full version of the book, please get the full copy here. You will also be able to access the full source code of the project.