Mobile Apps

app is an installable program that extends the functionality of the mobile device
- must be written and compiled for a particular mobile operating system

iOS Apps

in iOS, apps are distributed via Apple’s App Store
- must be submitted to and approved by Apple before they are released to users
- referred to as the walled garden model
- designed to prevent the spread of malware or code that could cause faults or crashes
Apps can use a variety of commercial models:
- free to use
- free with in-app purchases
- paid-for
Third-party developers can create apps for iOS using Xcode and the programming language Swift
- Apple’s integrated development environment (IDE)
- Xcode can only be installed and run on a computer using macOS

Android’s app model is more relaxed
apps available from both Google Play Store and third-party sites, such as Amazon’s app store
Java-based IDE, Android Studio, is available on Linux, Windows, and macOS

iOS and Android apps are supposed to run in a sandbox and have only the privileges granted by the user
- app will normally prompt when it needs to obtain permissions
- can edit permissions via the app’s Settings page