Arrays 筛选和映射数组时的SwiftUI EXC_BAD_指令
我有一个名为“课程”的实体,它包括:Arrays 筛选和映射数组时的SwiftUI EXC_BAD_指令,arrays,swift,filter,swiftui,exc-bad-instruction,Arrays,Swift,Filter,Swiftui,Exc Bad Instruction,我有一个名为“课程”的实体,它包括: @NSManaged public var timeMinutes: Double @NSManaged public var id: UUID @NSManaged public var lessonDescription: String @NSManaged public var date: Dates @NSManaged public var date: Date “日期”属性通过一对多关系链接到单独的“日期”实体,该实体包括: @NSManag
@NSManaged public var timeMinutes: Double
@NSManaged public var id: UUID
@NSManaged public var lessonDescription: String
@NSManaged public var date: Dates
@NSManaged public var date: Date
“日期”属性通过一对多关系链接到单独的“日期”实体,该实体包括:
@NSManaged public var timeMinutes: Double
@NSManaged public var id: UUID
@NSManaged public var lessonDescription: String
@NSManaged public var date: Dates
@NSManaged public var date: Date
我现在正试图显示一个图表,其中包含按“日期”求和的“timeMinutes”。此最终光线将具有以下结构:
struct FinalArray {
let summedMinutes : Double
let date : Date
}
生成(和显示)此数组的代码如下所示:
import SwiftUI
import SwiftUICharts
struct Test: View {
@Environment(\.managedObjectContext) var managedObjectContext
@FetchRequest(fetchRequest: Lessons.allLessonsFetchRequest()) var lessons: FetchedResults<Lessons>
var finalArray = [FinalArray]()
init(){
let allKeys = Set<Date>(lessons{$0.date.date})
for key in allKeys {
let sum = lessons.filter({$0.date.date == key}).map({$0.timeMinutes}).reduce(0, +)
finalArray.append(FinalArray(summedMinutes:sum, date:key))
}
finalArray = finalArray.sorted(by: {$0.date < $1.date})
}
var body: some View {
VStack{
LineView(data: finalArray.map {$0.summedMinutes}, title: "This graph returns empty").padding()
LineView(data: lessons.map {$0.timeMinutes}, title: "This graph works").padding()
}
}
}
有人知道我怎么解决这个问题吗?这是什么原因
如果我在视图中对核心数据进行ForEach,它可以正常工作:
var dateFormatter: DateFormatter {
let formatter = DateFormatter()
formatter.dateStyle = .long
return formatter
}
ForEach(lessons.map {$0.date.date}, id: \.self) { item in
VStack{
Text("\(item, formatter: self.dateFormatter)")
Text(String(self.lessons.filter{$0.date.date == item}.map {$0.timeMinutes}.reduce(0, +)))
}
}
这段代码可以工作,但它不是我想要的,我想在数组中显示总计的“timeMinutes”。任何想法或解决方法都将是非常受欢迎的 在查看初始更新时获取
课程
,但在init
中尚未定义它,因此尝试在其中使用它会导致崩溃
以下是可能的方法:
@State private var finalArray = [FinalArray]()
var body: some View {
VStack{
LineView(data: finalArray.map {$0.summedMinutes}, title: "This graph returns empty").padding()
LineView(data: lessons.map {$0.timeMinutes}, title: "This graph works").padding()
}
.onAppear {
let allKeys = Set<Date>(lessons{$0.date.date})
for key in allKeys {
let sum = lessons.filter({$0.date.date == key}).map({$0.timeMinutes}).reduce(0, +)
finalArray.append(FinalArray(summedMinutes:sum, date:key))
}
finalArray = finalArray.sorted(by: {$0.date < $1.date})
}
}
@State private var finalArray=[finalArray]()
var body:一些观点{
VStack{
LineView(数据:finalArray.map{$0.summedMinutes},标题:“此图返回空”).padding()
LineView(数据:lessons.map{$0.timeMinutes},标题:“此图有效”).padding()
}
奥纳佩尔先生{
让allKeys=Set(课程{$0.date.date})
用于输入所有键{
让sum=lessons.filter({$0.date.date==key}).map({$0.timeMinutes}).reduce(0,+)
追加(finalArray(summedMinutes:sum,date:key))
}
finalArray=finalArray.sorted(按:{$0.date<$1.date})
}
}
查看初始更新时会获取课程
,但在init
中尚未定义课程,因此尝试在其中使用课程会导致崩溃
以下是可能的方法:
@State private var finalArray = [FinalArray]()
var body: some View {
VStack{
LineView(data: finalArray.map {$0.summedMinutes}, title: "This graph returns empty").padding()
LineView(data: lessons.map {$0.timeMinutes}, title: "This graph works").padding()
}
.onAppear {
let allKeys = Set<Date>(lessons{$0.date.date})
for key in allKeys {
let sum = lessons.filter({$0.date.date == key}).map({$0.timeMinutes}).reduce(0, +)
finalArray.append(FinalArray(summedMinutes:sum, date:key))
}
finalArray = finalArray.sorted(by: {$0.date < $1.date})
}
}
@State private var finalArray=[finalArray]()
var body:一些观点{
VStack{
LineView(数据:finalArray.map{$0.summedMinutes},标题:“此图返回空”).padding()
LineView(数据:lessons.map{$0.timeMinutes},标题:“此图有效”).padding()
}
奥纳佩尔先生{
让allKeys=Set(课程{$0.date.date})
用于输入所有键{
让sum=lessons.filter({$0.date.date==key}).map({$0.timeMinutes}).reduce(0,+)
追加(finalArray(summedMinutes:sum,date:key))
}
finalArray=finalArray.sorted(按:{$0.date<$1.date})
}
}