iOS Swift 3:当尝试从自定义tableviewheader按钮Segue时，未识别的选择发送到实例

Question

我试图在点击一个自定义tableViewHeader单元格中的UIButton后segue。我的代码:

自定义标头:

class MealsMealPlanHeaderTableViewCell: UITableViewHeaderFooterView {
  @IBOutlet weak var mealLabel: UILabel!
  @IBOutlet weak var mealCalories: UILabel!
  @IBOutlet weak var editMeal: UIButton!
}

相关的ViewController代码:

class MealsMealPlanViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
  @IBOutlet weak var tableView: UITableView!
  let sections = ["Breakfast", "Lunch", "Dinner", "Snacks"]
  let foods = ["Oatmeal", "Sandwich", "Yogurt"]
  let portions = ["160 calories, 1 cup", "200 calories, 1 serving", "80 calories, 1 cup"]
  let headerId = "mealPlanHeader"
  let cellId = "mealPlanCell"
  override func viewDidLoad() {
    super.viewDidLoad()
    tableView.dataSource = self
    tableView.delegate = self
    tableView.register(UINib(nibName: "MealsMealPlanTableViewCell", bundle: nil), forCellReuseIdentifier: cellId)
    tableView.register(UINib(nibName: "MealsMealPlanHeaderTableViewCell", bundle: nil), forHeaderFooterViewReuseIdentifier: headerId)
  }
  override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
  }
  func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
    let headerCell = tableView.dequeueReusableHeaderFooterView(withIdentifier: headerId) as! MealsMealPlanHeaderTableViewCell
    headerCell.mealLabel?.text = self.sections[section]
    headerCell.mealCalories?.text = "400"
    headerCell.editMeal.tag = section
    headerCell.editMeal.addTarget(self, action: #selector(didPress(sender:)), for: UIControlEvents.touchUpInside)
    return headerCell.contentView
  }

  func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: cellId, for: indexPath) as! MealsMealPlanTableViewCell
    cell.foodLabel?.text = self.foods[indexPath.row]
    cell.foodCaloriePortion?.text = self.portions[indexPath.row]
    return cell
  }
  @IBAction func didPress(sender: AnyObject) {
    print("hello")
    self.performSegue(withIdentifier: "mealDetail", sender: sender)
  }
  override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "mealDetail" {
      print("made segue")
    }
  }
  func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return foods.count
  }
  func numberOfSections(in tableView: UITableView) -> Int {
    return sections.count
  }
  func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
    return 100
  }

我定义了一个segue从问题中的ViewController到故事板中的ViewController目的地，并带有正确的标识符。我知道segue会导致崩溃因为当performSegue被移除时，只调用IBAction就可以了。有什么想法或替代解决方案吗?

编辑:我的错误显示如下:

2016-10-27 16:15:11.105 Army H.E.A.L.T.H.[9344:478088] ***         Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Army_H_E_A_L_T_H_.MealsMealDetailViewController tableView:numberOfRowsInSection:]: unrecognized selector sent to instance 0x7fc94f535bf0'

Answer 1

你的异常告诉你问题:"——[Army_H_E_A_L_T_H_。MealsMealDetailViewController tableView:numberOfRowsInSection:]:未识别的选择器发送到实例你必须设置MealsMealDetailViewController作为一些UITableView的数据源，但你实际上没有实现UITableViewDataSource协议。你的应用崩溃是因为它实例化了tableView, tableView向你的ViewController询问行数Objective C运行时抛出异常因为它找不到那个方法在你的ViewControllerer或它的任何超类上。