使用CoreData，我是否能够存储UITextView文本并从UITableView行中检索该文本

Question

在Swift中，我创建了两个独立的VC，一个是UITextView，另一个是UITableView。UITableView就像一个项目列表，可以单独滑动到编辑/删除。如果选择编辑，它将转到UITextView。通过使用CoreData（我碰巧是新用户），我想通过在UITableView行上滑动Edit来再次检索UITextView中的文本/数据。因此，基本上，如果已经创建了UITableViewRow，并且在其UITextView中添加了文本，那么TableRow（项目）如何可能专门指向保存的UITextView？我只是想知道，这可能吗？这就是我未来的计划：

这样做：

• 当用户创建一个新项目（在UITableView中（作为一行））时，这将创建一个可以编辑、保存和删除的全新UITextView
• 当用户选择编辑现有的UITableViewRow（项目）时，它将使用创建时的数据切换到UITextView

StackOverflow用户可以告诉我什么来指导我吗？也许我会用什么来说明细节等等。

非常感谢！感谢

更新，代码：

import UIKit
class SecondViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, UIAlertViewDelegate, UITextFieldDelegate {
    @IBOutlet weak var tableView: UITableView!
    @IBOutlet weak var toolbar: UIToolbar!
    @IBOutlet weak var addButton: UIBarButtonItem!
    @IBOutlet weak var createButton: UIBarButtonItem!
    var projects: [String] = []
    var deleted: [String] = []
    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.delegate = self
        tableView.dataSource = self
    }
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "FourthViewController" {
            let destination = segue.destinationViewController as FourthViewController
            destination.deletedItems = deleted
        } else {
            fatalError("unhandled segue "(segue.identifier)"")
        }
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
    func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 1
    }
    // Use this for swipe table view cell
    func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
        if editingStyle == UITableViewCellEditingStyle.Delete {
            self.deleted.append(self.projects[indexPath.row])
            projects.removeAtIndex(indexPath.row)
            tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.Automatic) } }

    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return projects.count
    }
    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell
        // Set the label text as the project name
        cell.textLabel!.text = projects[indexPath.row]

        return cell
    }
    func alertView(alertView: UIAlertView, clickedButtonAtIndex buttonIndex: Int) {
        if buttonIndex == 1 {
            if let name = alertView.textFieldAtIndex(0)?.text {
                projects.append(name)
                tableView.reloadData()
            }
        }
    }
    // Add button
    @IBAction func addButtonPressed(sender: AnyObject) {
        var alert = UIAlertView(title: "Enter the title", message: "This will be the name of your project", delegate: self, cancelButtonTitle: "Cancel")
        alert.alertViewStyle = UIAlertViewStyle.PlainTextInput
        alert.addButtonWithTitle("Continue")
        alert.show()
    }
    // Swipe
    func tableView(tableView: UITableView, editActionsForRowAtIndexPath indexPath: NSIndexPath) -> [AnyObject]?  {
        // Delete
        var deleteButton = UITableViewRowAction(style: .Default, title: "Delete", handler: { (action, indexPath) in
            self.tableView.dataSource?.tableView?(self.tableView, commitEditingStyle: .Delete, forRowAtIndexPath: indexPath)
            println(self.projects)
            println(self.deleted)
            return
        })
        deleteButton.backgroundColor = UIColor.redColor()

    // Edit

        var editAction = UITableViewRowAction(style: UITableViewRowActionStyle.Default, title: "Edit" , handler: { (action:UITableViewRowAction!, indexPath:NSIndexPath!) -> Void in

            let editMenu = UIAlertController(title: nil, message: "Edit this project", preferredStyle: .ActionSheet)
            let editAction = UIAlertAction(title: "Edit", style: UIAlertActionStyle.Default, handler: { action in
                var vc = self.storyboard?.instantiateViewControllerWithIdentifier("ThirdViewController") as ThirdViewController
                self.presentViewController(vc, animated: true, completion: nil)
                })
            let cancelAction = UIAlertAction(title: "Cancel", style: UIAlertActionStyle.Cancel, handler: nil)
            editMenu.addAction(editAction)
            editMenu.addAction(cancelAction)

            self.presentViewController(editMenu, animated: true, completion: nil)
        })
        editAction.backgroundColor = UIColor.lightGrayColor()

        return [deleteButton, editAction]



    }
}

TextView的代码：

import UIKit
class ThirdViewController: UIViewController, UITextViewDelegate {
    @IBOutlet weak var myTextView: UITextView!
    @IBOutlet weak var editButton: UIBarButtonItem!

    override func viewDidLoad() {
        super.viewDidLoad()
        myTextView.delegate = self
        // Do any additional setup after loading the view.
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {
        // Combine the new text with the old
        let combinedText = (textView.text as NSString).stringByReplacingCharactersInRange(range, withString: text)
        // Create attributed version of the text
        let attributedText = NSMutableAttributedString(string: combinedText)
        attributedText.addAttribute(NSFontAttributeName, value: textView.font, range: NSMakeRange(0, attributedText.length))
        // Get the padding of the text container
        let padding = textView.textContainer.lineFragmentPadding
        // Create a bounding rect size by subtracting the padding
        // from both sides and allowing for unlimited length
        let boundingSize = CGSizeMake(textView.frame.size.width - padding * 2, CGFloat.max)
        // Get the bounding rect of the attributed text in the
        // given frame
        let boundingRect = attributedText.boundingRectWithSize(boundingSize, options: NSStringDrawingOptions.UsesLineFragmentOrigin, context: nil)
        // Compare the boundingRect plus the top and bottom padding
        // to the text view height; if the new bounding height would be
        // less than or equal to the text view height, append the text
        if (boundingRect.size.height + padding * 2 <= textView.frame.size.height){
            return true
        }
        else {
            return false
        }
    }
    @IBAction func Edit(sender: AnyObject) {
        editButton.title = "Save"
    }


}

Answer 1

这绝对是可行的。我相信有多种方法可以实现这一点，但是，我建议通过prepareForSegue传递这些数据。

您要做的第一件事是在textViewController上创建一个var来存储传递的数据对象（这需要是所发送对象类型的var）。一旦创建了这个var，就可以在prepareForSegue调用中获取数据，然后将其传递给textViewControllers var.

例如：

---

NSManaged对象

import Foundation
import CoreData
    @objc(Project)
    class Project: NSManagedObject {
        @NSManaged var text: String
        @NSManaged var person: Person
    }

import Foundation
import CoreData
    @objc(Person)
    class Person: NSManagedObject {
        @NSManaged var name: String
        @NSManaged var tasks: NSSet
    }

---

TableViewController

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) 
{
   // First get the cell that was selected
   let cell = sender as UITableViewCell
   let indexPath = tableView.indexPathForCell(cell)
   // Next setup your destination view controller
   let textViewVC = segue.destinationViewController as ProjectTextViewVC
   // Now fetch the individual object for the select cell
   let project = fetchedResultsController.objectAtIndexPath(indexPath!) as Project // Replace 'Project' with the name of your NSManagedObject
   // Last thing is to pass over the object to the destination view controller. 
   textViewVC.project = project 
}

---

TextViewController

class ProjectTextViewController: UITextViewController {
    var project: Project? = nil
    override func viewDidLoad() {
       super.viewDidLoad()
       textArea.text = project.text
    }
}