85 lines
2.8 KiB
Markdown
85 lines
2.8 KiB
Markdown
# iOS and Cross-Platform Development
|
|
|
|
|
|
|
|
| | Android | iOS |
|
|
| -------------------- | :-------------------------: | :---------------------------: |
|
|
| Market Share | 82% | 13.9% |
|
|
| Programming Lang | Java<br />Kotlin | Objective-C<br />Swift (2014) |
|
|
| IDE | Eclipse<br />Android Studio | Xcode |
|
|
| OS | Windows/Mac/Linux | Only on Mac! |
|
|
| Distribution Process | Release can take hours | Release can take weeks |
|
|
| Fees | \$24 one-off | \$99 per year |
|
|
|
|
### iOS
|
|
|
|
- Based heavily on Mac OS X
|
|
- Closed source
|
|
- Tools, deployment, app ecosystem controlled by Apple
|
|
- Apps can only be installed from the App Store
|
|
- Cryptographically signed
|
|
- Apple runs App Store
|
|
- Approves all apps available from it
|
|
|
|
#### iOS Apps
|
|
|
|
- Written in Objective-C & Swift
|
|
- An extension of C to add support for objects
|
|
- Using the Cocoa Touch UI framework
|
|
- Can also use C/C++ libraries
|
|
- Compiles to native code via LLVM (not interpreted (JIT) as on Android)
|
|
|
|
##### Structure of an App
|
|
|
|
**M**odel **V**iew **C**ontroller Design Pattern
|
|
|
|
|
|
|
|
**UI Application Object**: manages event loop & high-level app behaviour
|
|
|
|
**Application Delegate**: Handles app initialisation and state transitions
|
|
|
|
**Data Objects**: Store data for the app (images, database, etc.)
|
|
|
|
**Document**: Manage data objects
|
|
|
|
**View Controller**: Manages the presentation of the app on the screen, loads views, shows views, rotates views, etc.
|
|
|
|
**UI Window**: Coordinates the presentation of one or more views on a screen
|
|
|
|
**Views & UI objects**: Draw content, buttons, etc.
|
|
|
|
##### iOS Lifecycle
|
|
|
|
- Apps are sandboxed; inter-app communication is used to pass data
|
|
- Only one application in the foreground / visible at once
|
|
- A main loop processes events for the application
|
|
- Xcode creates the main function
|
|
- App can be in a number of significant states
|
|
- Active: foreground
|
|
- Inactive: foreground but interrupted
|
|
- Background: same as services in Android
|
|
- Suspended: main loop no longer running; remains in memory but is potentially killed by the operating system
|
|
|
|
##### State Transitions
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
#### App Store
|
|
|
|
- Pre-moderation
|
|
- Apple checks all applications in advance manually
|
|
- Versus Android: publish and then revoke
|
|
- A long list of guidelines as to what is appropriate
|
|
|
|
## Cross-platform
|
|
|
|
#### Xamarin
|
|
|
|
- Developed by Microsoft
|
|
- `xamarin.Forms` for native UI code
|