[英]Start and End date of month in SwiftUI
如何根據 SwiftUI 中的選定日期獲取 startDateOfMonth 和 endDateOfMonth?
我為 Swift (DateComponents) 找到了一些答案,但無法使其與 SwiftUI 一起使用。
為什么我需要這個:我將使用使用謂詞的動態過濾器來過濾當前選定月份中的所有數據(使用自定義控件切換月份)。 但首先我需要獲取每個選定月份的開始和結束日期。
示例代碼:
內容視圖.swift
import SwiftUI
struct ContentView: View {
@State var currentDate = Date()
// How to make startDateOfMonth and endDateOfMonth dependent on selected month?
@State private var startDateOfMonth = "1st January"
@State private var endDateOfMonth = "31st January"
var body: some View {
VStack {
DateView(date: $currentDate)
Text("\(currentDate)")
Text(startDateOfMonth)
Text(endDateOfMonth)
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
日期視圖.swift
import SwiftUI
struct DateView: View {
static let dateFormat: DateFormatter = {
let formatter = DateFormatter()
formatter.setLocalizedDateFormatFromTemplate("yyyy MMMM")
return formatter
}()
@Binding var date : Date
var body: some View {
HStack {
Image(systemName: "chevron.left")
.padding()
.onTapGesture {
print("Month -1")
self.changeDateBy(-1)
}
Spacer()
Text("\(date, formatter: Self.dateFormat)")
Spacer()
Image(systemName: "chevron.right")
.padding()
.onTapGesture {
print("Month +1")
self.changeDateBy(1)
}
}
.padding(EdgeInsets(top: 5, leading: 10, bottom: 5, trailing: 10))
.background(Color.yellow)
}
func changeDateBy(_ months: Int) {
if let date = Calendar.current.date(byAdding: .month, value: months, to: date) {
self.date = date
}
}
}
struct DateView_Previews: PreviewProvider {
struct BindingTestHolder: View {
@State var testItem: Date = Date()
var body: some View {
DateView(date: $testItem)
}
}
static var previews: some View {
BindingTestHolder()
}
}
我設法通過以下 ContentView 實現來解決它
@State var currentDate = Date()
private var startDateOfMonth: String {
let components = Calendar.current.dateComponents([.year, .month], from: currentDate)
let startOfMonth = Calendar.current.date(from: components)!
return format(date: startOfMonth)
}
private var endDateOfMonth: String {
var components = Calendar.current.dateComponents([.year, .month], from: currentDate)
components.month = (components.month ?? 0) + 1
components.hour = (components.hour ?? 0) - 1
let endOfMonth = Calendar.current.date(from: components)!
return format(date: endOfMonth)
}
var body: some View {
VStack {
DateView(date: $currentDate)
Text("\(currentDate)")
Text(startDateOfMonth)
Text(endDateOfMonth)
}
}
private func format(date: Date) -> String {
let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .medium
return dateFormatter.string(from: date)
}
因為currentDate
由 DateView 通過 Binding 更改,所以將調用主體計算屬性,因此startDateOfMonth
和endDateOfMonth
計算屬性將返回更新后的值。
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