如何在swiftui中的分组列表上实现移动 [英] how to implement move on a grouped list in swiftui

问题描述

如何在分组列表中实现 onMove 函数?不幸的是，我看不到从哪里获得到公司"的信息...

how do i implement the onMove function in a grouped list? unfortunately i cannot see where i get the "to company" information from...

代码如下:

import SwiftUI


struct Person: Identifiable, Hashable {
    var id = UUID()
    var name: String
}

struct Company : Identifiable, Hashable {

    var id = UUID()
    var name: String
    var employees : [Person]
}

class CompanyList: ObservableObject {

    @Published var companies = [
        Company(name: "Apple", employees: [Person(name:"Bob"), Person(name:"Brenda")]),
        Company(name: "Microsoft", employees: [Person(name:"Bill"), Person(name:"Lucas")]),
         Company(name: "Facebook", employees: [Person(name:"Mark"), Person(name:"Sandy")])
    ]

    func deleteListItem(whichElement: IndexSet, from company: Company) {

        let index = companies.firstIndex(of: company)!

        companies[index].employees.remove(atOffsets: whichElement)
    }

    func moveListItem(whichElement: IndexSet, to companyIndex: Int) {

        print(whichElement.first)
        if whichElement.count > 1 {
            whichElement.dropFirst()
            print(whichElement.first)
        }
        print(companyIndex)

//        let employee = companies[index].employees[whichElement.first!]
//        companies[index].employees.remove(at: whichElement.first!)
//
    }
}

struct  ContentView: View {
    @ObservedObject var companyList = CompanyList()
    @State var text : String = ""

    var body: some View {
        NavigationView {
            VStack {
                List () {
                    ForEach (companyList.companies, id: \.self) { company in
                        Section(header: Text(company.name)) {
                            ForEach(company.employees) { employee in

                                Text(employee.name).id(UUID())
                            }
                            .onDelete { (indexSet) in
                                self.companyList.deleteListItem(whichElement: indexSet, from: company)
                            }

                            .onMove { indexSet, intValue in
                                self.companyList.moveListItem(whichElement: indexSet, to: intValue)
                            }
                            .onInsert(of: ["chris"]) { (intValue, _) in
                                print("wtf")
                            }
                        }
                    }
                }
                .listStyle(GroupedListStyle())
                .navigationBarItems(trailing: EditButton())
            }
        }
    }
}

推荐答案

有 2 个主要变化和 1 个 swiftUI 缺点.

There is 2 main changes and 1 swiftUI drawback.

1. 更新方法moveListItem

通过使用 NavigationalLink 移动，创造了更换公司的替代方案

Created a alternative to change companies by moving with a NavigationalLink

SwiftUI 无法使用 .onMove()

SwiftUI have no option to move between groups in GroupedList with .onMove()

该应用在技术上有效.但除非 Apple 添加该功能，否则不会如您所愿.还有一个选项，那就是使用自定义移动方法创建自定义列表视图，这是一个完全不同的主题.

The app works technically. But not as you intended unless Apple add the feature. There is one more option, that is to create custom list view with custom move method, which is entirely a different topic.

import SwiftUI

struct Person: Identifiable, Hashable {
    var id = UUID()
    var name: String
}

struct Company : Identifiable, Hashable {
    var id = UUID()
    var name: String
    var employees : [Person]
}

class CompanyList: ObservableObject {
    @Published var companies = [
        Company(name: "Apple", employees: [Person(name:"Bob"), Person(name:"Brenda")]),
        Company(name: "Microsoft", employees: [Person(name:"Bill"), Person(name:"Lucas")]),
        Company(name: "Facebook", employees: [Person(name:"Mark"), Person(name:"Sandy")])
    ]

    func deleteListItem(whichElement: IndexSet, from company: Company) {
        if let index = self.companies.firstIndex(of: company) {
            self.companies[index].employees.remove(atOffsets: whichElement)
        }
    }

    func moveListItem(whichElement: IndexSet, to companyIndex: Int, from company: Company) {
        if let index = self.companies.firstIndex(of: company) {
            self.companies[index].employees.move(fromOffsets: whichElement, toOffset: companyIndex)
        }
    }
}


struct  TestView: View {
    @EnvironmentObject var companyList: CompanyList
    @State var text : String = ""

    var body: some View {
        NavigationView {
            VStack {
                List () {
                    ForEach (companyList.companies, id: \.self) { company in
                        Section(header: Text(company.name)) {
                            ForEach(company.employees) { employee in
                                NavigationLink(destination: EditEmployee(company: company, employee: employee)){
                                    Text(employee.name)
                                }.id(UUID())
                            }
                            .onDelete { (indexSet) in
                                self.companyList.deleteListItem(whichElement: indexSet, from: company)
                            }
                            .onMove { indexSet, intValue in
                                self.companyList.moveListItem(whichElement: indexSet, to: intValue, from: company)
                            }
                            .onInsert(of: ["chris"]) { (intValue, _) in
                                print("wtf")
                            }
                        }
                    }
                }
                .listStyle(GroupedListStyle())
                .navigationBarItems(trailing: EditButton())
            }
        }
    }
}


struct EditEmployee: View {
    @EnvironmentObject var companyList: CompanyList
    var company: Company
    var employee: Person
    var body: some View {
        VStack(alignment: .leading) {
            Text("Company")
            Picker(selection: Binding<Company>(
                get: { () -> Company in
                    return self.company
            }, set: { (company) in
                if let cid = self.companyList.companies.firstIndex(of: self.company) {
                    if let eid =  self.companyList.companies[cid].employees.firstIndex(of: self.employee) {
                        if let ncid = self.companyList.companies.firstIndex(of: company) {
                            self.companyList.companies[cid].employees.remove(at: eid)
                            self.companyList.companies[ncid].employees.append(self.employee)
                        }
                    }
                }
            }
            ), label: Text("")){
                ForEach(self.companyList.companies) { company in
                    Text(company.name).tag(company)
                }
            }.pickerStyle(SegmentedPickerStyle())
            Spacer()
        }.padding()
            .navigationBarTitle(self.employee.name)
    }
}

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