100 days of swiftUI

Day49: project 10 cupcake corner
Add codable conformance for@Published property/use of enum CodingKeys:CodingKey

Required keyword: force to implement init
URLSession run in background thread and dispatchqueue.main.async to main thread for UI update
Disable forms

Day 50:
Use order class as Data mode, class conform to ObservableObject/properties with @published  annotation, use computed property at order class to validate address/calculate order total

Day 51:
Encode Order class: conforms to codable and add codingkeys, decoder implementation
Use URLRequest to send data, use https://requires.in as a mock server.
Note URLSession.shared.dataTask() won’t start if we don’t call resume()
Thus always write the task and call resume before actually fill the data body.

Day 52: cupcake corner wrap up

Grand central Dispatch to control multithread tasks/switch between threads

The @Published property wrapper places our property inside a Published struct

URLRequest described how days should be fetched

Day 53:
Core data first glance: access managed object content by using environment wrapper
@Environment(\.managedObjectContext)
@FetchRequest(entity)…

Use Binding to create two way data link between views (structs)

Day54:
Project 11 part 2
- use core data to create book object, note, sheet need to pass in moc object( the environment data does not share from ancestor view)
- and start rating view and logic is fun- unset star is optional image

Day 55 Bookworm part3
Moc.delete to delete entry at core data
Sorting with fetchRequest - NSSortDescriptor, specifies multiple sort parameter by their orders
Use alert to pop current view off the view stack

Use a static NSManagedObjectContext object in preview to display entry at core data( import Coredata first)

Day 56 book worm wrap up:
Type eraser/@@Binding/@Environment
How to create a test object at preview
Sheet (view) does not share environment with parent views
Challenges

Day57: more on core data
- hashable protocol
- add unique constraint to core data property/ create NSmanagedObject subclass manually (uncheck generate class definitions)
- conditional save when core data object hasChanged

Day 58:
Coredata p2:
Filter @fetchRequest using NSPredict
Each filter request present it’s view - use a generic filter request view to pass in filter key, and use view Builder to let the filter decide it’s view
How to create 1-many relationship at core data