我正试图通过prepareForSegue()将一个对象传递给另一个场景,
override func prepareForSegue(segue: UIStoryboardSegue,sender: AnyObject?) {
// Get the new view controller using [segue destinationViewController].
var nextScene = segue.destinationViewController as! VehicleDetailsTableViewController
// Pass the selected object to the new view controller.
if let indexPath = self.tableView.indexPathForSelectedRow() {
let selectedVehicle = vehicles[indexPath.row]
nextScene.currentVehicle = selectedVehicle
}
}
而且我有currentVehicle对象来捕捉这些对象.但是,当我尝试运行时,它会崩溃并且收到关于downcasting的错误.
编辑错误
Could not cast value of type ‘XXX.DisplayViewController’
(0x1082dcd80) to ‘XXX.VehicleDetailsTableViewController’
(0x1082dc9a0). (lldb)
解决方法
你必须在故事板中给出一个标识符(说mySegue)
使用XCode 7,swift 2.x
override func prepareForSegue(segue: UIStoryboardSegue,sender: AnyObject?){....}
被调用为所有segues被称为形式您当前的UIViewController.所以识别者是区分不同的段落
然后使用这段代码：
override func prepareForSegue(segue: UIStoryboardSegue,sender: AnyObject?) {
if segue.identifier == "mySegue" {
var nextScene = segue.destinationViewController as! VehicleDetailsTableViewController
// Pass the selected object to the new view controller.
if let indexPath = self.tableView.indexPathForSelectedRow {
let selectedVehicle = vehicles[indexPath.row]
nextScene.currentVehicle = selectedVehicle
}
}
}
使用Xcode 8,swift 3.x
override func prepare(for segue: UIStoryboardSegue,sender: Any?) {
if segue.identifier == "mySegue",let nextScene = segue.destination as? VehicleDetailsTableViewController,let indexPath = self.tableView.indexPathForSelectedRow {
let selectedVehicle = vehicles[indexPath.row]
nextScene.currentVehicle = selectedVehicle
}
}
在nextScene之后放置一个断点,看看它是否在单击TableView中的任何单元格时被触发.如果不是,则故事板中提供的标识符名称必须与此处给出的不同.
