如何将每周、每月和每年的间隔添加到循环中的日期？

Question

我正在使用 for 循环将项目附加到数组以添加到 Realm。

var transactionArray:[Transaction] = []

for _ in 1...numberOfTransactionsToAdd {

            let addedTransaction = Transaction()
            
            addedTransaction.transactionAmount = amount
            addedTransaction.transactionName = name
            addedTransaction.transactionDescription = desc
            addedTransaction.transactionDate = datePicked
            addedTransaction.transactionCategory = category

            transactionArray.append(addedTransaction)
        }

let transactionList = List<Transaction>()
        
        
        for transaction in transactionArray {
            
            transactionList.append(transaction)
            
        }
        
        try! realm.write {
            realm.add(transactionList)
        }

此代码运行良好，但它保存了同一日期的所有交易。

我需要通过将每周和每月的时间间隔添加到日期来使他们重复交易。

我尝试创建一个嵌套的 for 循环来添加日期组件：

for _ in 0...1 {
                datePicked = Calendar.current.date(byAdding: timeComponent, to: datePicked)!
            }

我已经尝试增加几个星期的时间，但这几个月都行不通：

for _ in 0...7 {
                datePicked = datePicked + 24*60*60
            }

如何以每周和每月的间隔附加这些 addedTransaction 对象？

Answer 1

有一个现有的答案，但它依赖于第三方模块，这不是一件坏事，但如果将来不更新，它将使答案无效。此外，使用的对象没有明确定义。

TL;DR - 不需要列表或数组。在创建和填充事务时编写事务。

详情：

所以这里有一个更完整的 Swift 答案，从 TransactionClass Realm 对象开始，该对象具有交易日期的便利 init 以及通常在对象上使用的主键。

class TransactionClass: Object {
    @objc dynamic var transaction_id = UUID().uuidString
    @objc dynamic var date_picked = Date()
    convenience init(theDate: Date) {
        self.init()
        self.date_picked = theDate
    }
    override static func primaryKey() -> String? {
        return "transaction_id"
    }
}

然后是一个根据pickDate创建多个重复交易的函数

let datePicked = Date() //using today as an example, insert your date here
let numMonths = 12 //recurring for 12 months
var dateComponent = DateComponents()

for index in 0..<numMonths {
    dateComponent.month = index
    if let futureDate = Calendar.current.date(byAdding: dateComponent, to: datePicked) {
        let t = TransactionClass(theDate: futureDate)
        try! realm.write {
            realm.add(t)
        }
    }
}

以及打印时的输出

2020-07-12 13:30:32 +0000
2020-08-12 13:30:32 +0000
2020-09-12 13:30:32 +0000
2020-10-12 13:30:32 +0000
2020-11-12 14:30:32 +0000
2020-12-12 14:30:32 +0000
2021-01-12 14:30:32 +0000
2021-02-12 14:30:32 +0000
2021-03-12 14:30:32 +0000
2021-04-12 13:30:32 +0000
2021-05-12 13:30:32 +0000
2021-06-12 13:30:32 +0000

Answer 2

如果我正确理解了你的问题，你可以试试这个：

for _ in 1...numberOfTransactionsToAdd {
    let addedTransaction = Transaction()

    addedTransaction.transactionAmount = amount
    addedTransaction.transactionName = name
    addedTransaction.transactionDescription = desc
    addedTransaction.transactionCategory = category
    
    // specify your date components (add month, day, whatever you need)
    var dateComponent = DateComponents() 
    dateComponent.day = 1
    dateComponent.month = 2
    // add the date components to `datePicked`
    let newDate = Calendar.current.date(byAdding: dateComponent, to: datePicked)!
    // set `transactionDate` to your new date
    addedTransaction.transactionDate = newDate

    transactionArray.append(addedTransaction)
}

Answer 3

这是我解决这个难题的方法：

我使用 SwiftDate https://cocoapods.org/pods/SwiftDate 来更轻松地处理日期。

我在循环结束时添加了一个月到 datePicked，在 transactionArray.append 之后。这样，第一个交易日期就是选择的日期。

代码如下：

func saveMultipleTransactions() {
        
        var transactionArray:[Transaction] = []
        
        let numberOfTransactionsToAdd = 12
        
        for _ in 1...numberOfTransactionsToAdd {
            
            let addedTransaction = Transaction()
                        
            addedTransaction.transactionAmount = amount
            addedTransaction.transactionName = name
            addedTransaction.transactionDescription = desc
            addedTransaction.transactionDate = datePicked
            addedTransaction.transactionCategory = category
            
            transactionArray.append(addedTransaction)
            
            datePicked = datePicked + 1.months
            
        }
        
        let transactionList = List<Transaction>()
        
        
        for transaction in transactionArray {
            
            transactionList.append(transaction)
            
        }
        
        try! realm.write {
            realm.add(transactionList)
        }
    }

我计划扩展功能以使其更加通用，但这对我有用（目前）。