我对 Swift 完全陌生。我需要遍历一个数组，并根据数据是什么，构建一个自定义的树结构。我会分享我的代码，但它太笨重而且太可怕了，无法在公共场合看到。它甚至不接近工作。所以这里有一些伪代码：
pass in an array of ScheduleCell models (data for a scheduled tv program) to a SwiftUI View.
Each ScheduleCell contains:
Date of broadcast
Channel
Starttime
Program title, subtitle, etc
in the view body, loop over each ScheduleCell
if ScheduleCell is new day then
display new date
go down one line
end
if ScheduleCell is new channel then
display ScheduleCell.channel but do NOT drop down a line
end
display ScheduleCell.title, also on same line as channel
Keep going on the same horizontal line till you hit the next channel
end
最终效果应该是这样的：
11-16-2021
CNN News Program 1 News Program 2 News Program 3 Etc.
NBC Late Show Infomercial Barney Miller Rerun. Etc.
11-17-2021
CNN News Program 1 News Program 2 News Program 3 Etc.
NBC Late Show Infomercial Barney Miller Rerun. Etc.
看起来这样做应该很简单。我尝试设置树结构，但 SwiftUI View 协议遇到问题。我尝试在视图主体之外的函数中构建树结构，但我无法弄清楚如何将该结构放入视图主体。
或者，我已经放弃了所有这些，只是试图通过跟踪数组索引来通过视图内部的蛮力使其工作，如下所示：
struct ScheduleDisplayView: View {
var schedule: [SchedSlot]
let dfdo = DateFormatter.dateOnly
let dfto = DateFormatter.timeOnly
let chanwidth: CGFloat = 45.0
let fontsize: CGFloat = 10.0
var body: some View {
List {
ForEach(schedule.indices,id:\.self) { idx in
let ssDay: String = dfdo.string(from: schedule[idx].startTime!)
let ssChan: Int32 = schedule[idx].channel!.channelID
if idx == 0 ||
ssDay != dfdo.string(from: schedule[idx-1].startTime!)
{
VStack {
Text(ssDay)
.frame(maxWidth: 200 + chanwidth, alignment: .leading)
}
}
HStack {
if idx == 0 ||
ssChan != schedule[idx-1].channel!.channelID
{
VStack {
Text(String(schedule[idx].channel!.channelID))
.frame(maxWidth: chanwidth, alignment: .center)
//.font(.system(size: fontsize))
Text(schedule[idx].channel!.callSign!)
.frame(maxWidth: chanwidth, alignment: .center)
//.font(.system(size: fontsize))
}
}
Text(schedule[idx].program!.title!)
.frame(maxWidth: 200, alignment: .leading)
.border(Color.black)
}
}
}
}
}
但上述方法不起作用，因为 HStack 不能将程序标题保持在同一行。
提前感谢您的任何意见。
附加材料：
下面是一些基于 CoreData 实体的随机切片：
SchedCell
stationID starttime programID duration endtime isUsed channel program
34916 2021-09-29 19:09:00.000 EP000045050088 PT00H09M 2021-09-29 19:18:00.000 0
12131 2021-09-29 19:15:00.000 EP022222100024 PT00H15M 2021-09-29 19:30:00.000 0
34916 2021-09-29 19:18:00.000 EP000045050208 PT00H09M 2021-09-29 19:27:00.000 0
Program
series programID title subtitle fulldescription genre isUsed
EP00000066 EP000000660001 A Pup Named Scooby-Doo Night of the Living Burger After a quarrel, a burgerlike creature haunts Shaggy and Scooby. Children 0
EP00000066 EP000000660002 A Pup Named Scooby-Doo For Letter or Worse The ghost of a long-dead gangster haunts a TV studio. Children 0
EP00000066 EP000000660003 A Pup Named Scooby-Doo A Bicycle Built for Boo! A green monster steals Shaggy's bike. Children 0
EP00000066 EP000000660004 A Pup Named Scooby-Doo The Baby Sitter From Beyond The baby sitter for Shaggy's little sister appears to be a monster. Children 0
Channel
stationID callSign fullName channelID isUsed
15722 WCIX WCIX 2 0
11345 WCIA WCIA 3 0
11278 WAND WAND 4 0
10685 KSDK KSDK 5 0
10269 HSN Home Shopping Network 6 0
11824 WRSP WRSP 7 0
11069 QVC QVC 8 0
至于我尝试在视图之外构建树结构的代码示例，我没有工作代码。这只是产生各种错误消息的片段。这是节点结构。我仍在制定将它们组装成工作树的例程，一旦我有值得一看的东西就会发布：
class RootNode {
var children: [DayNode] = []
func add(child: DayNode) {
children.append(child)
child.parent = self
}
}
class DayNode {
var parent: RootNode
var date: String
var children: [ChannelNode] = []
init(date: String) {
self.date = date
}
func add(child: ChannelNode) {
children.append(child)
child.parent = self
}
}
class ChannelNode {
var parent: DayNode
var channel: String
var children: [SchedSlot] = []
init(channel: String) {
self.channel = channel
}
func add(child: SchedSlot) {
children.append(child)
//child.parent = self
}
}
