EXC_BAD_INSTRUCTION 将 UICollectionView 单元格数据传递给不同的 ViewController 时 [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.我创建了填充 UICollectionView 的自定义单元格:

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)

    }
}

我试图访问 UICollectionView 中单击的单元格的 pollQuestion 变量并将其传递给另一个 ViewController:

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
        }
    }
}

投票控制器:

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.
  }

}

更新:我已经修改了代码，现在收到错误

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

应用程序在运行时崩溃，我正在尝试解决:

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

推荐答案

崩溃是因为在调用 prepare(for segue) 时，出口 passLabel 尚未连接.

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

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

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
    }

...

在prepare(for segue)中设置变量而不是标签的text属性:

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
    }
}

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.

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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