cs193p

Lecture 13: Publisher More Persistence
- publishers
- more persistence
- cloudKit
- coredata

## 0:39 Publisher
- what is publisher?
- what can we do with a Publisher?
- listening (subscribing) to a Publisher
- .sink
- .onReceive
- where do Publisher come from?
- URLSession
- Timer
- NotificationCenter

11:54 Code

class Document: ObserableObject {
    @Published var backgroundImage: UIImage?
}

var document = Document() 
document.$backgoundImage  <--- 取得 Publisher 實體

// 而以下如此是做 Bind
$document.background

## 35:28 More Persistence

cloudKit
API 使用

47:26 CoreData
API 使用

@ObservedObject
@FetchRequest

# Lecture 14: Document Architecture

* App and Scene
* Document Architecture
* Components of a "document-oriented" app

## App Architecture

- `App` protocol
- `Scene` protocol
- WindowGroup { }
- DocumentGroup(newDocument:) { }
- DocumentGroup(viewing:) { }
- `@SenceStorage`
- `@AppStorage`
- `@ScaledMetric`

7:48 Code

app icon -> Asset.xcassets

19:56 `RawRepresentable`

每次開啟 app 後 load backgroundImage 完成又去 zoomToFit

## 28:02 Document Architecture

FileDocument
ReferenceFileDocument
UTType
Document Types
39:05 Undo

func undoablyPerform(operation: String, with undoManager: UndoManager?) {
    let oldModel = model
    doIt()
    undoManager?.registerUndo(withTarget: self) { mySelf in
        mySelf.model = oldModel
    }
    undoManager?.setActionName(operation)
}

## 43:14 Back To Code

- 49:50 讓 **ViewModel** conform to `ReferenceFileDocument`
- 1:02:16 undo imple
- 1:12:01 support document

cocoaError(.fileReadCorrup)