我的问题是：

Question

我正在编写一个任务应用程序，我正在尝试从用户那里收集输入，并使用它来显示更新的UITableView和用户创建的任务。

我的问题是：

用户任务列表没有正确追加（每次添加任务时，数据的内容都没有被追加，而是被替换。
taskTable UITableView没有正确显示任务结构数组的内容。

TaskManager.swift类接收任务详细信息并向数组添加任务结构。

import UIKit

struct task{
var name: String
var desc: String
var due_date: String

init(name: String, desc: String, due_date: String)
{
    self.name = name
    self.desc = desc
    self.due_date = due_date
}
}

var TaskMgr: TaskManager = TaskManager()


class TaskManager: UIViewController {
var tasks = [task]()

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

/*
 *   Purpose: Add new task to task array
 *   Parameters: task (struct) to add
 *   Return: n/a
 */
func addTask(name: String, desc: String, due_date: String) {
    print("got to add task method")
    tasks.append(task(name: name, desc: desc, due_date: due_date))

    print("value of tasks[0] is:",tasks[0])
    print("number of elements in array: ",tasks.count)
    //the task array count should increase as the user adds more tasks,
    //but from this code, it is replacing elements 
    //(only saying there is one element, the most recently added one)

}

这是FirstViewController.swift类，其中输入从新任务屏幕读取，并发送到TaskManager类以添加到任务列表。

import UIKit

//display task class
class FirstViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

@IBOutlet weak var taskTable: UITableView!

@IBOutlet weak var taskName_txt: UITextField!
@IBOutlet weak var taskDesc_txt: UITextField!
@IBOutlet weak var taskDueDate_txt: UIDatePicker!
@IBOutlet weak var taskDone_btn: UIBarButtonItem!
@IBOutlet weak var addTask_btn: UIBarButtonItem!

var activeTextField = UITextField()


//Cancel task button function
@IBAction func cancelTask_btn(_ sender: Any) {
    performSegue(withIdentifier: "backToTasks_seg", sender: cancelTask_btn)
}


override func viewDidLoad() {
    super.viewDidLoad()
    //taskTable.reloadData()
    //taskTable.reloadData()

}

@IBAction func addTaskPressed(_ sender: Any) {
    performSegue(withIdentifier: "addTask_seg", sender: taskDone_btn)
}

func textFieldDidBeginEditing(textField: UITextField) {

    self.activeTextField = textField
    activeTextField.backgroundColor = UIColor(red: 187.00, green: 128.00, blue: 74.00, alpha: 1.00)
}


/*
 *   Purpose: Triggered off user 'Done' button click
        Creates a task to add
 *   Parameters: button clicked
 *   Return: n/a
 */
@IBAction func doneTaskInput_btn(_ sender: Any) {
    print("Done task input button pressed")

    //if user input is valid, create a task from data they input
    //return back to task table screen
    if(isInputValid() != false){

        let name = taskName_txt.text!
        print("Task name is: ",name)
        let desc = taskDesc_txt.text!
        print("Task desc is: ",desc)

        let due_date = handler(sender: taskDueDate_txt)
        print("Task due date is: ",due_date)
        print("Adding task to task list...")


        TaskManager().addTask(name: name, desc: desc, due_date: due_date)


    }//end check isValid

    //added task to array, now go back to task table to display tasks
    performSegue(withIdentifier: "backToTasks_seg", sender: taskDone_btn)


}//end function


/*
*   Purpose: checks if user entered a task name
*   Parameters: none
*   Return: true if user entered task name
        false otherwise
*/
func isInputValid()-> Bool{

    var taskName: String?

    if taskName != ""{
        taskName = taskName_txt.text
        return true
    }else{
        taskName_txt.backgroundColor = UIColor.red
        taskName_txt.placeholder = "Add a task name"
        return false
    }

}//end isInputValid method

/*
 *   Purpose: Parses date from UIDatePicker to string
 *   Parameters: DatePicker to read date from
 *   Return: formatted string date
 */
func handler(sender: UIDatePicker)->String {

    let timeFormatter = DateFormatter()
    timeFormatter.dateFormat = "dd-MM-yyyy HH:mm"

    let strDate = timeFormatter.string(from: taskDueDate_txt.date)

    return strDate
}//end handler method


/*
 *   Purpose: Remove cell
 *   Parameters: task table, edit value
 *   Return: n/a
 */
func tableView(taskTable: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath){
    if (editingStyle == UITableViewCellEditingStyle.delete){

        TaskMgr.tasks.remove(at: indexPath.row)
        taskTable.reloadData()
    }
}

/*
 *   Purpose: Returns number of sections (columns) in table
 *   Parameters: table
 *   Return: number of sections (colums)
 */
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    print( "setting number of sections");
    return 1
}



/*
 *   Purpose: Returns number of rows in array to the table view
 *   Parameters: taskTable, number of rows
 *   Return: number of rows (int)
 */
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return TaskMgr.tasks.count // taskList.count
}

/*
 *   Purpose: Populate cells with data from array of task structs
 *   Parameters: task table, row to insert data
 *   Return: populated cell
 */
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell: UITableViewCell = UITableViewCell(style:     UITableViewCellStyle.subtitle, reuseIdentifier: "Default Tasks")
    cell.textLabel?.text = TaskMgr.tasks[indexPath.row].name
    cell.detailTextLabel!.text = TaskMgr.tasks[indexPath.row].desc

    return cell
}

}

感谢您的帮助！

Answer 1

除非您使用像Rx这样的东西，否则iOS中没有数据绑定。这意味着如果您更改了您负责的数据，请告诉tableView使用reloadData或insertRows(at:with:)更新自己。

有一个问题，你想在哪里做到这一点。在简单的情况下，您可以在添加后立即执行此操作。在更复杂的情况下，您订阅来自TaskManager的通知，并且taskmanager会在数据发生变化时发送您的视图控制器消息（这使您的数据保持同步，这是多个视图控制器，我假设您有一个单独的TaskManager）。

并不是说你已经在删除了。

Answer 2

每次你看到任务管理器视图控制器，它都是一个新实例时，我有一种感觉吗？

var tasks = [task]()

这可能也会重置它？我尝试将tasks数组放在FirstViewController中，然后你可以直接访问它里面的结构。

在TableView中显示结构数组

我的问题是：

2 个答案: