将UICollectionView单元格数据传递给不同的ViewController时EXC_BAD_INSTRUCTION [英] EXC_BAD_INSTRUCTION When Passing UICollectionView Cell Data to Different ViewController

问题描述

我有一个基于Firebase数据填充的UICollectionView。我已经创建了自定义单元格来填充UICollectionView：

pre $ import $ UI $
import材料

类PollCell：CollectionViewCell {

var key：String？ {
获得{
返回self.key
}
}
@IBOutlet弱var imageView：UIImageView！
@IBOutlet weak var pollQuestion：UILabel！

public required init（coder aDecoder：NSCoder）{
super.init（coder：aDecoder）

我尝试访问UICollectionView中单击单元格的pollQuestion变量，并将其传递给另一个ViewController：

  override func prepare（for segue：UIStoryboardSegue，sender：Any？）{
 if segue.identifier ==toPoll{
让pollViewController = segue.destination as！ PollController 
如果让cell = sender as？ PollCell {
 pollViewController.passLabel.text = cell.pollQuestion.text 
} 
} 
} 
  

$ b $ p

PollController：

$ p $ import UIKit

类PollController： UIViewController {

@IBOutlet弱var passLabel：UILabel！

覆盖func viewDidLoad（）{
super.viewDidLoad（）

//在加载视图之后执行其他任何设置。
}

覆盖func didReceiveMemoryWarning（）{
super.didReceiveMemoryWarning（）
//处理任何可以重新创建的资源。

code










$ b $ p


$ b

更新：我已经修改了代码，现在收到错误



该应用程序在运行时崩溃，我试图解决：

解决方案

passLabel 在准备（for segue 被调用。

您必须在 PollController 中声明一个（临时）变量，并在 viewDidLoad

  class PollController：UIViewController {
 
 @IBOutlet weak var passLabel：UILabel！
 
 var pass =
 
覆盖func viewDidLoad（）{
 super.viewDidLoad（）
 passLabel.text = pass 
} 
 
 ... 
  

在准备（for segue 设置变量而不是文本标签的属性：

 让pollViewController = segue.destination as！ PollController 
如果让cell = sender as？ PollCell {
 pollViewController.pass = cell.pollQuestion.text 
} 
} 
  

注意：不建议从视图（单元格）收集信息。获取索引路径并从模型（数据源数组）中读取信息。

I have a UICollectionView that I am populating based on Firebase data. I have created custom cells that populate the UICollectionView:

import UIKit
import Material

class PollCell: CollectionViewCell {

var key: String? {
get {
return self.key
}
}
@IBOutlet weak var imageView: UIImageView!
@IBOutlet weak var pollQuestion: UILabel!

public required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)

    }
}

I am attempting to access the pollQuestion variable of the clicked cell in the UICollectionView and pass it to another ViewController:

     override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "toPoll" {
    let pollViewController = segue.destination as! PollController
        if let cell = sender as? PollCell {
            pollViewController.passLabel.text = cell.pollQuestion.text
        }
    }
}

PollController:

import UIKit

class PollController: UIViewController {

@IBOutlet weak var passLabel: UILabel!

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.
  }

}

UPDATE: I have revised the code and am now receiving the error

The app is crashing at runtime, and I am trying to resolve:

解决方案

The crash occurs because the outlet passLabel is not connected yet when prepare(for segue is called.

You have to declare a (temporary) variable in PollController and set the label in viewDidLoad

class PollController: UIViewController {

    @IBOutlet weak var passLabel: UILabel!

    var pass = ""

    override func viewDidLoad() {
        super.viewDidLoad()
        passLabel.text = pass
    }

...

In prepare(for segue set the variable rather than the text property of the label:

let pollViewController = segue.destination as! PollController
    if let cell = sender as? PollCell {
        pollViewController.pass = cell.pollQuestion.text
    }
}

Note: It's not recommended to gather information from the view (cell). Get the index path and read the information from the model (data source array).

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