如何在TableView中按日期筛选数组？附myAlert示例JSON数据

Hey there! Let's work through how to implement date-based filtering for your TableView using that myAlert JSON data you shared. I'll walk you through a complete Swift implementation (since it's the most common for iOS TableViews these days), and you can adapt it to your needs easily.

First, let's turn that raw JSON into a Swift model so we can work with it more safely and cleanly. We'll use Codable to handle the JSON parsing:

struct AlertModel: Codable {
    let usaTime: String
    let vsTitle: String
    let vsStartTime: String
    let vsEndTime: String
    let vsStatus: String
    let vsAddTime: String
    
    // Map the snake_case JSON keys to camelCase Swift properties
    enum CodingKeys: String, CodingKey {
        case usaTime = "usa_time"
        case vsTitle = "vs_title"
        case vsStartTime = "vs_start_time"
        case vsEndTime = "vs_end_time"
        case vsStatus = "vs_status"
        case vsAddTime = "vs_add_time"
    }
}

Date handling can be tricky, so let's make a reusable formatter to parse and format the dates consistently. We'll add an extension to DateFormatter:

extension DateFormatter {
    static let alertDateFormatter: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd HH:mm:ss" // Matches your JSON date format
        formatter.locale = Locale(identifier: "en_US_POSIX")
        formatter.timeZone = TimeZone(secondsFromGMT: 0) // Adjust this if you need to account for time zones
        return formatter
    }()
    
    // Helper to extract just the date part (no time) as a string
    static func getDateOnlyString(from dateString: String) -> String? {
        guard let fullDate = alertDateFormatter.date(from: dateString) else { return nil }
        let dateOnlyFormatter = DateFormatter()
        dateOnlyFormatter.dateFormat = "yyyy-MM-dd"
        return dateOnlyFormatter.string(from: fullDate)
    }
}

Let's say you want to filter alerts where the vs_start_time falls on a specific date (like "2018-04-29"). Here's how you can do that:

// Your original array of alerts (after parsing the JSON)
var originalAlerts: [AlertModel] = []
// Your filtered array to use as TableView data source
var filteredAlerts: [AlertModel] = []

// Example target date (you could get this from a date picker, user input, etc.)
let targetDate = "2018-04-29"

// Perform the filter
filteredAlerts = originalAlerts.filter { alert in
    // Get the date-only string from the alert's start time
    guard let alertDate = DateFormatter.getDateOnlyString(from: alert.vsStartTime) else {
        return false // Skip alerts with invalid date strings
    }
    // Match against the target date
    return alertDate == targetDate
}

If you want to filter by a different date field (like vs_add_time), just swap out alert.vsStartTime with alert.vsAddTime in the code above.

Once you have the filtered array, update your TableView's data source and refresh it:

// Assign the filtered array to your TableView data source
tableViewDataSource = filteredAlerts
// Refresh the TableView to show the filtered results
yourTableView.reloadData()

If you want users to pick a date via a UIDatePicker to trigger filtering, add this handler:

@objc func datePickerDidChange(_ sender: UIDatePicker) {
    let dateOnlyFormatter = DateFormatter()
    dateOnlyFormatter.dateFormat = "yyyy-MM-dd"
    let selectedDateString = dateOnlyFormatter.string(from: sender.date)
    
    // Re-filter the alerts
    filteredAlerts = originalAlerts.filter { alert in
        guard let alertDate = DateFormatter.getDateOnlyString(from: alert.vsStartTime) else {
            return false
        }
        return alertDate == selectedDateString
    }
    
    // Update the TableView
    tableViewDataSource = filteredAlerts
    yourTableView.reloadData()
}

• Date Range Filtering: If you need to filter alerts between two dates (instead of a single date), compare Date objects directly instead of strings:

  let startDate = Date() // Your start date
  let endDate = Date().addingTimeInterval(86400) // 1 day after start date
  
  filteredAlerts = originalAlerts.filter { alert in
      guard let startTime = DateFormatter.alertDateFormatter.date(from: alert.vsStartTime) else {
          return false
      }
      return startTime >= startDate && startTime <= endDate
  }
  

• Error Handling: Make sure to handle cases where date parsing fails (like invalid date strings in the JSON) to avoid crashes.

内容的提问来源于stack exchange，提问作者Palak Patel