Question

我有视图控制器subMenuViewController，它通过两个不同的段来链接，称为DBSubLegislationSegue和TrafficSegue。

当用户从动态表中选择一个单元格时，代码应该检查选择了哪一行，并且根据单元格将执行正确的segue到新的viewController。

当我运行代码时，应用程序总是会在正确的视图控制器上结束，但是它通过执行两个segue来完成此操作，第一个segue始终是Traffic Segue。

任何人都可以协助确定为什么要进行这种双重扫描吗？

//populates the table with instances of SubMenuViewCell for each instance filling its label with the correct menuItems
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell =
    self.tableView.dequeueReusableCellWithIdentifier(
        "SubMenuCell", forIndexPath: indexPath)
        as! SubMenuTableViewCell

    let row = indexPath.row
    cell.subMenuLabel.font =
        UIFont.preferredFontForTextStyle(UIFontTextStyleHeadline)
    cell.subMenuLabel.text = subMenuItems[row]
    cell.accessoryType = UITableViewCellAccessoryType.DisclosureIndicator //adds disclosure arrow indicating further info to cell

    return cell
}

//function for handling when a table row is selected by the user.
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    //get the selected row index and save as rowSelected
    let myIndexPath = self.tableView.indexPathForSelectedRow()
    rowSelected = myIndexPath!.row
    println(rowSelected)
    if(rowSelected == 0){
        performSegueWithIdentifier("DBSubLegislationSegue", sender: nil)
    }
    if(rowSelected == 1){
        performSegueWithIdentifier("DBSubLegislationSegue", sender: nil)
    }
    if(rowSelected == 2){
        performSegueWithIdentifier("DBSubLegislationSegue", sender: nil)
    }
    if(rowSelected == 3){
        performSegueWithIdentifier("DBSubLegislationSegue", sender: nil)
    }
    if(rowSelected == 4){
        performSegueWithIdentifier("DBSubLegislationSegue", sender: nil)
    }
    if(rowSelected == 5){
       performSegueWithIdentifier("TrafficSegue", sender: nil)
    }
    if(rowSelected == 6){
        performSegueWithIdentifier("DBSubLegislationSegue", sender: nil)
    }
    if(rowSelected == 7){
        performSegueWithIdentifier("DBSubLegislationSegue", sender: nil)
    }
    if(rowSelected == 8){
        performSegueWithIdentifier("DBSubLegislationSegue", sender: nil)
    }
    if(rowSelected == 9){
        performSegueWithIdentifier("DBSubLegislationSegue", sender: nil)
    }
    if(rowSelected == 10){
        performSegueWithIdentifier("DBSubLegislationSegue", sender: nil)
    }
    if(rowSelected == 11){
        performSegueWithIdentifier("DBSubLegislationSegue", sender: nil)
    }

 }

// MARK: - Navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    println(segue.identifier)
    if segue.identifier == "DBSubLegislationSegue" && rowSelected == 0 { //check the row and act appropriately
        let newViewController = segue.destinationViewController    //set the new viewController(new page)
            as! LegislationDBQueryTableViewController
        newViewController.typeOfPage = "All Entries"
    }
    if segue.identifier == "DBSubLegislationSegue" && rowSelected == 1 { //check the row and act appropriately
        let newViewController = segue.destinationViewController     //set the new viewController(new page)
            as! LegislationDBQueryTableViewController
        newViewController.typeOfPage = "Common Law"
    }
    if segue.identifier == "DBSubLegislationSegue" && rowSelected == 2 { //check the row and act appropriately
        let newViewController = segue.destinationViewController     //set the new viewController(new page)
            as! LegislationDBQueryTableViewController
        newViewController.typeOfPage = "Police Procedure"
    }
    if segue.identifier == "DBSubLegislationSegue" && rowSelected == 3 { //check the row and act appropriately
        let newViewController = segue.destinationViewController     //set the new viewController(new page)
            as! LegislationDBQueryTableViewController
        newViewController.typeOfPage = "Police Powers"
    }
    if segue.identifier == "DBSubLegislationSegue" && rowSelected == 4 { //check the row and act appropriately
        let newViewController = segue.destinationViewController     //set the new viewController(new page)
            as! LegislationDBQueryTableViewController
        newViewController.typeOfPage = "Crime"
    }
    if segue.identifier == "TrafficSegue" && rowSelected == 5 { //check the row and act appropriately
        let newViewController = segue.destinationViewController     //set the new viewController(new page)
            as! TrafficSubMenuTableViewController
    }
    if segue.identifier == "DBSubLegislationSegue" && rowSelected == 6 { //check the row and act appropriately
        let newViewController = segue.destinationViewController     //set the new viewController(new page)
            as! LegislationDBQueryTableViewController
        newViewController.typeOfPage = "People"
    }
    if segue.identifier == "DBSubLegislationSegue" && rowSelected == 7 { //check the row and act appropriately
        let newViewController = segue.destinationViewController     //set the new viewController(new page)
            as! LegislationDBQueryTableViewController
        newViewController.typeOfPage = "Civil Order"
    }
    if segue.identifier == "DBSubLegislationSegue" && rowSelected == 8 { //check the row and act appropriately
        let newViewController = segue.destinationViewController     //set the new viewController(new page)
            as! LegislationDBQueryTableViewController
        newViewController.typeOfPage = "Sexual"
    }
    if segue.identifier == "DBSubLegislationSegue" && rowSelected == 9 { //check the row and act appropriately
        let newViewController = segue.destinationViewController     //set the new viewController(new page)
            as! LegislationDBQueryTableViewController
        newViewController.typeOfPage = "Licencing"
    }
    if segue.identifier == "DBSubLegislationSegue" && rowSelected == 10 { //check the row and act appropriately
        let newViewController = segue.destinationViewController     //set the new viewController(new page)
            as! LegislationDBQueryTableViewController
        newViewController.typeOfPage = "Firearms"
    }
    if segue.identifier == "DBSubLegislationSegue" && rowSelected == 11 { //check the row and act appropriately
        let newViewController = segue.destinationViewController     //set the new viewController(new page)
            as! LegislationDBQueryTableViewController
        newViewController.typeOfPage = "Terrorism"
    }

}

Answer 1

您正在获得双重分段，因为通过控制拖动在故事板上创建的segue会自动被调用。换句话说，由于您已经通过故事板创建了segues，因此没有理由调用class Channel < ActiveRecord::Base belongs_to :bmc has_and_belongs_to_many :customer_segments validates :name, presence: true validate :require_at_least_one_customer_segment private def require_at_least_one_customer_segment if customer_segments.count == 0 errors.add_to_base "Please select at least one customer segment" end end end class CostStructure < ActiveRecord::Base belongs_to :bmc has_and_belongs_to_many :customer_segments validates :name, presence: true validate :require_at_least_one_customer_segment private def require_at_least_one_customer_segment if customer_segments.count == 0 errors.add_to_base "Please select at least one customer segment" end end end class CustomerSegment < ActiveRecord::Base has_and_belongs_to_many :channels has_and_belongs_to_many :cost_structures end。假设您已在故事板中正确设置了标识符，则其余代码将按原样正常工作，因此您可以继续删除或注释掉performSegueWithIdentifier方法的内容。

我建议在准备segue时使用else-ifs，例如：

tableview.didSelectRowAtIndexPath

Answer 2

全部修复。

我的错误是第一个segue我将动态CELL连接到下一个视图控制器但是我的第二个segue从表视图本身连接到视图控制器。

通过确保从表视图本身连接两者，代码按预期工作。

为什么我的代码执行双segue？

2 个答案: