更新

查看this answer
看起来.listRowInsets不适用于使用内容初始化的List中的行
所以只要稍微修改一下代码就可以做到这一点。首先，你需要从post视图中删除padding，这样文本就会移到边缘（如果你想这样做的话）：

struct PostView: View {
  let placeholder = UIImage(named: "arianaGrande")!
  var post: Post

  var body: some View {
    VStack {
      HStack {
        Text(post.album).font(.title)
        Spacer()
        Text(post.artist)
      }// .padding() -- This padding adds space before "Sweetener and after Ariana Grande

      Image(uiImage: placeholder)
        .resizable()
        .aspectRatio(placeholder.size,  contentMode: .fit)
      HStack {
        Image("plus-icon")
        Spacer()
        Image("comment-icon")
        Spacer()
        Image("headset-icon")
      }.padding()

      HStack {
        Text(post.username)
        Spacer()
        Text(post.textContent)
      }//.padding() -- Same thing here.
    }
  }
}

struct PostView_Previews: PreviewProvider {
  static var previews: some View {
    PostView(post: Post(
      artist: "Ariana Grande",
      album: "Sweetener",
      albumArtUrl: "",
      username: "DoesData",
      textContent: "Text Content"
      )
    )
  }
}

然后，您可以稍微不同地初始化列表以删除空格。

struct PostsView: View {
  var posts = [
    Post(
      artist: "Ariana Grande",
      album: "Sweetener",
      albumArtUrl: "",
      username: "DoesData",
      textContent: "Text Content"
    )
  ]

  var body: some View {
    List {
      ForEach(posts) { post in
        PostView(post: post)
          .listRowInsets(EdgeInsets())
      }
    }
  }
}

struct Post: Identifiable {
  let id = UUID()
  let artist: String
  let album: String
  let albumArtUrl: String
  let username: String
  let textContent: String
}

struct PostsView_Previews: PreviewProvider {
  static var previews: some View {
    PostsView()
  }
}

测试结果：

原始答案

看起来你可以调整列表本身的padding来删除前导和尾随边距。

import SwiftUI

struct PostsView: View {
   @ObservedObject var fbVM = FirebaseInfo()

    var body: some View {

       List(fbVM.visiblePosts) { post in
            PostView(post: post)
       }.padding(.horizontal, -20) // -20 seems to make it go edge to edge

    }
}

struct PostsView_Previews: PreviewProvider {
    static var previews: some View {
        PostsView()
    }
}

您可能还需要调整PostView内部的填充，以使文本像这样Text("Title").font(.title).padding(.leading, -10)这似乎比它应该的更复杂，但它似乎工作。

列表中有几种间距可以更改。看看这个彩色编码的Map，并选择一个适合您的需求：

List(1...100, id: \.self) { item in
    Text("\(item)")
        .padding() // 🟣 comment to remove PURPLE padding
        .background(Color.yellow)
        // .listRowInsets(EdgeInsets()) // 🔵 uncomment to remove BLUE inset
}
// .listStyle(.plain) // 🟢 uncomment to remove GREEN inset
// .listStyle(.grouped) // 🔴 uncomment to remove RED inset

RTL-Demo

重要提示：

看起来.listRowInsets不适用于使用内容初始化的List中的行。因此，您需要在list中使用ForEach，如下所示：

var body: some View {
    List {
        ForEach(...) {
            Text("String")
                .listRowInsets(EdgeInsets())
        }
    }
}