根据布尔值进入不同的视图控制器

Posted 2023-02-27

【中文标题】根据布尔值进入不同的视图控制器

【英文标题】：Proceed to different view controllers based on boolean value

【发布时间】：2015-11-27 00:49:10

【问题描述】：

当一个表格单元被选中时，如果布尔值为真，我会尝试进入视图控制器，否则（如果为假），则进入另一个视图控制器。任何帮助都会很棒！ （布尔值是 isAdmin，如果为 true，则继续进行 eventViewController，否则继续进行 UserEventTableViewController）

项目链接： https://www.dropbox.com/s/1d4d8opuxzpcuk4/TicketekApp.zip?dl=0

代码：

import UIKit

class EventTableViewController: UITableViewController 
// MARK: Properties

var events = [Event]()
var isAdmin = false
override func viewDidLoad() 
    super.viewDidLoad()

    // Use the edit button item provided by the table view controller.
    navigationItem.leftBarButtonItem = editButtonItem()

    // Load any saved events, otherwise load sample data.
    if let savedEvents = loadEvents() 
        events += savedEvents
     else 
        // Load the sample data.
        loadSampleEvents()
    


func loadSampleEvents() 
    let photo1 = UIImage(named: "event1")!
    let event1 = Event(name: "ACDC", photo: photo1, rating: 4, price: 500.0, eventDescription: "Album", album: "Album1")!

    let photo2 = UIImage(named: "event2")!
    let event2 = Event(name: "Cold Play", photo: photo2, rating: 5, price: 500.0, eventDescription: "Album", album: "Album1")!

    let photo3 = UIImage(named: "event3")!
    let event3 = Event(name: "One Direction", photo: photo3, rating: 3, price: 500.0, eventDescription: "Album", album: "Album1")!

    events += [event1, event2, event3]


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


// MARK: - Table view data source

override func numberOfSectionsInTableView(tableView: UITableView) -> Int 
    return 1


override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int 
    return events.count


override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell 
    // Table view cells are reused and should be dequeued using a cell identifier.
    let cellIdentifier = "EventTableViewCell"
    let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! EventTableViewCell

    // Fetches the appropriate event for the data source layout.
    let event = events[indexPath.row]

    cell.nameLabel.text = event.name
    cell.photoImageView.image = event.photo
    cell.ratingControl.rating = event.rating
    cell.priceLabel.text = event.album

    return cell


// Override to support conditional editing of the table view.
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool 
    // Return false if you do not want item to be editable.
    return true



// Override to support editing the table view.
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) 
    if editingStyle == .Delete 
        // Delete the row from the data source
        events.removeAtIndex(indexPath.row)
        saveEvents()
        tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
     else if editingStyle == .Insert 
        // Create new instance of  class, add to the array, and add a new row to the table
    



/*
// Override to support rearranging the table view.
override func tableView(tableView: UITableView, moveRowAtIndexPath fromIndexPath: NSIndexPath, toIndexPath: NSIndexPath) 


*/

/*
// Override to support conditional rearranging of the table view.
override func tableView(tableView: UITableView, canMoveRowAtIndexPath indexPath: NSIndexPath) -> Bool 
// Return false if you do not want the item to be re-orderable.
return true

*/


// MARK: - Navigation

// preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) 
    if segue.identifier == "ShowDetail" 
        let eventDetailViewController = segue.destinationViewController as! EventViewController

        // Get the cell that generated this segue.
        if let selectedEventCell = sender as? EventTableViewCell 
            let indexPath = tableView.indexPathForCell(selectedEventCell)!
            let selectedEvent = events[indexPath.row]
            eventDetailViewController.event = selectedEvent
            print(selectedEventCell)
        
    
    else if segue.identifier == "AddItem" 
        print("Adding new event.")
    



@IBAction func unwindToMealList(sender: UIStoryboardSegue) 
    if let sourceViewController = sender.sourceViewController as? EventViewController, event = sourceViewController.event 
        if let selectedIndexPath = tableView.indexPathForSelectedRow 
            // Update an existing event.
            events[selectedIndexPath.row] = event
            tableView.reloadRowsAtIndexPaths([selectedIndexPath], withRowAnimation: .None)
         else 
            // Add a new event.
            let newIndexPath = NSIndexPath(forRow: events.count, inSection: 0)
            events.append(event)
            tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Bottom)
        
        // Save the events.
        saveEvents()
    


// MARK: NSCoding

func saveEvents() 
    let isSuccessfulSave = NSKeyedArchiver.archiveRootObject(events, toFile: Event.ArchiveURL.path!)
    if !isSuccessfulSave 
        print("Failed to save events...")
    


func loadEvents() -> [Event]? 
    return NSKeyedUnarchiver.unarchiveObjectWithFile(Event.ArchiveURL.path!) as? [Event]

【问题讨论】：

prepareForSegue 来不及改变segue；您需要从场景中的 UIViewController 对象链接您的 segue，然后实现 didSelectRowAtIndexPath - 在此方法中，您可以使用 performSegueWithIdentifier 根据您需要的任何逻辑调用所需的 segue

【参考方案1】：

你必须实现 tableView 委托方法didSelectRowAtIndexPath。

示例如下：

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) 
    let index = self.tableView.indexPathForSelectedRow?.row
    //use the index to know which cell you selected

    //check for your condition here something like
    if isAdmin 
        performSegueWithIdentifier("eventViewControllerSegue", sender: self)
     else 
        performSegueWithIdentifier("userEventTableViewControllerSegue", sender: self)
    

注意以下几点：

在您的故事板中，将转场绘制到不同的视图控制器并分别分配转场 ID。

在您的代码中，您不会更改 isAdmin 布尔值。也检查一下。

问候。

关于如何从 ViewController 中分离的图片供您参考

【讨论】：

对不起，我是新手，但是当单击表格单元格时，我是否会将 segues 绘制到新的视图控制器，并且会是附件选择吗？

我相信只有在将 segue 从 tableViewCell 绘制到 destinationViewController 时才能看到辅助动作。理想情况下，您应该从 sourceViewController 手动绘制到destinationViewController

【参考方案2】：

我相信你可以通过使用 UITableViewDelegate 协议中的tableView:didSelectRowAtIndexPath: 来完成你想要的。

将此添加到您的视图控制器

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) 

并在该函数中处理您的逻辑。

当你准备好进入下一个视图控制器时，使用

performSegueWithIdentifier(identifier: String, sender: AnyObject?)

这是一个例子：

if isAdmin 
    performSegueWithIdentifier(identifier: "segueToAdminView", sender: self)
 else 
    performSegueWithIdentifier(identifier: "segueToUserEventView", sender: self)