小编T. *_*ter的帖子

如何向我的deleteRow()函数添加确认？A 已经添加了，.alert但我不知道如何继续。

List {
    ForEach(data, id: \.self) { item in
        Text(item)
        .alert(isPresented: self.$showingDeleteAlert) {
            Alert(title: Text("..."), message: Text("..."), primaryButton: .destructive(Text("Delete")) {
                deleteRow // ???
                }, secondaryButton: .cancel()
            )
        }
    }
    .onDelete(perform: deleteRow)
}

func deleteRow(at indexSet: IndexSet) {
    for index in indexSet {
        let item = data[index]
        viewContext.delete(item)
        do {
            try viewContext.save()
        } catch let error {
            print("Error: \(error)")
        }
    }
}
``

这是我的 Firestore 数据库： 更新锻炼常量后useEffect()，我只能访问名称和 uId。我如何才能访问文档 ID？

import React, { useState, useEffect } from "react";
import "./Workouts.sass";
import Workout from "./Workout";
import firebase from "./firebase";

function Workouts() {
  const [workouts, setWorkouts] = useState([]);

  useEffect(() => {
    let user = firebase.auth().currentUser;
    const database = firebase.firestore();
    const unsubscribe = database
      .collection("workouts")
      .where("uId", "==", user.uid)
      .onSnapshot((snapshot) => {
        setWorkouts(snapshot.docs.map((doc) => doc.data()));
      });

    return () => {
      unsubscribe();
    };
  }, []);

  return (
    <div className="Workouts">
      {workouts.map((workout) => (
        <Workout key={workout.name} workout={workout} />
      ))} …

我从 firestore 获取了由trained_on desc 订购的锻炼。

  useEffect(() => {
    let user = firebase.auth().currentUser;
    const database = firebase.firestore();
    const unsubscribe = database
      .collection("workouts")
      .where("uId", "==", user.uid)
      .orderBy("trained_on", "desc")
      .onSnapshot((snapshot) => {
        setWorkouts(
          snapshot.docs.map((doc) => ({ id: doc.id, ...doc.data() }))
        );
      });

    return () => {
      unsubscribe();
    };
  }, []);

这是忽略未设置trained_on 的条目。当我创建新的锻炼时，没有“trained_on”。

如何添加条目，其中trained_on也未定义？

我的应用程序意外启动了一个我以前从未遇到的错误,我无法在网络上找到任何解决方案.我认为这与我的代码无关,但如果有帮助,这里是:

class InterfaceController: WKInterfaceController {

@IBOutlet var tableView: WKInterfaceTable!

final let url = URL(string: "http://...")
private var tasks = [Task]()

override func awake(withContext context: Any?) {
    super.awake(withContext: context)

    downloadJson()

}

func downloadJson() {
    guard let downloadURL = url else { return }
    URLSession.shared.dataTask(with: downloadURL) { data, urlResponse, error in

        guard let data = data, error == nil, urlResponse != nil else {
            print("something is wrong")
            return
        }

        do
        {
            let decoder = JSONDecoder()
            let downloadedTasks = try decoder.decode(Tasks.self, from: data) …