I'm currently developing a SwiftUI application that utilizes SwiftData for data management. I am facing a challenge when trying to filter a query. Specifically, I want to filter a list of Item objects to match a Product instance that is passed to my View.
error :
Instance member 'product' cannot be used on type 'MainItemListEncap'; did you mean to use a value of this type instead
The view
//
// 311.1.1. MainRefToItem.swift
// ComparePrice
//
// Created by Herman VAN CAUWELAERT on 11/12/2024.
//
import SwiftUI
import SwiftData
struct MainItemListEncap: View {
@Bindable var product: Product
@Query(
filter: #Predicate { item in
item.productGroup == product
},
sort: [SortDescriptor(\Item.name)]
)
var items: [Item]
@Environment(\.modelContext) var modelContext
var body: some View {
ForEach(items) { item in
VStack(alignment: .leading) {
Text(item.name)
Text(item.description)
}
}
}
}
the product class.
import SwiftData
import Foundation
@Model
final class Product: CustomStringConvertible, CustomDebugStringConvertible {
@Attribute(.unique) var productName: String
var productDescription: String
var outputCurrency: String
// Gebruik een `String` als opslag voor `outputSystem`
var outputSystemRawValue: String = MeasurementSystem.metric.rawValue
// Computed property om `MeasurementSystem` te gebruiken
var outputSystem: MeasurementSystem {
get {
MeasurementSystem(rawValue: outputSystemRawValue)
}
set {
outputSystemRawValue = newValue.rawValue
}
}
// er zijn verschillend item versies voor een product
// als er een hoofdproduct gedelete wordt, dan zullen alle onderliggende items ook gedelete worden
@Relationship(deleteRule: .cascade, inverse: \Item.productGroup) var refToItems = [Item]()
init(productName: String = "", productDescription: String = "what is this product", outputCurrency: String = "EUR", outputSystem: MeasurementSystem = MeasurementSystem.metric) {
self.productName = productName
self.productDescription = productDescription
self.outputCurrency = outputCurrency
self.outputSystem = outputSystem
}
}
the item class
import Foundation
import SwiftData
@Model
final class Item: CustomStringConvertible, CustomDebugStringConvertible {
var timestamp: Date
@Attribute(.unique) var name: String
var productGroup: Product?
var shop: String //TODO: becomes Shop
var price: Double
var currency: String
var quantity: Double
var unit: String //TODO: becomes Unit
var isShown : Bool
var minimumQuantity: String
var rateStr: String {
conversionRate != nil ? " (rate: \(ValueFormatter.shared.format(conversionRate!)))" : ""
}
init(timestamp: Date = Date()
, name: String
, shop: String = "Colruyt"
, price:Double = 1.00
, currency: String = "EUR"
, quantity: Double = 1.0
, unit: String = "g"
, isShown:Bool = true
, conversionRate: Decimal? = 1
, minimumQuantity: String = "1"
) {
self.timestamp = timestamp
self.name = name
self.shop = shop
self.price = price
self.currency = currency
self.quantity = quantity
self.unit = unit
self.isShown = isShown
self.conversionRate = conversionRate
self.minimumQuantity = minimumQuantity
}
}
