ios swift performSegueWithIdentifier 发送者值
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swift performSegueWithIdentifier sender value
提问by Kiwo Tew
I am trying to understand how the sender value works in segues.
我试图了解发件人值如何在 segue 中工作。
In some places in my code both works:
在我的代码中的某些地方，两者都有效：
performSegueWithIdentifier("mySegue", sender: self)
performSegueWithIdentifier("mySegue", sender: sender)
But what is the difference between having self / sender?
但是拥有自我/发件人之间有什么区别？
回答by Duncan C
As @iosDev82 says in his answer, sender is an optional that names the object (if any) that triggered the segue.
正如@iosDev82 在他的回答中所说，sender 是一个可选的，它命名触发 segue 的对象（如果有的话）。
If you trigger a segue through code in a view controller, you could pass the view controller (self), or you could pass nil. It's just a piece of information that is passed along to prepareForSegue (again as iOSDv82 says.)
如果您通过视图控制器中的代码触发转场，您可以传递视图控制器（self），或者您可以传递 nil。这只是传递给 prepareForSegue 的一条信息（再次如 iOSDv82 所说。）
If you trigger a segue in the code of an IBAction method, your IBAction may have it's own sender parameter (frequently a button.) In that case you can pass along the sender parameter to the performSegueWithIdentifiermethod.
如果您在 IBAction 方法的代码中触发 segue，您的 IBAction 可能有它自己的 sender 参数（通常是一个按钮）。在这种情况下，您可以将 sender 参数传递给该performSegueWithIdentifier方法。
Example:
例子：
@IBAction func buttonAction(sender: UIButton)
{
//In this case the button IBAction takes a pointer to the button as a param.
//Pass it on to the segue in case performWithSegue needs it.
self.performSegueWithIdentifier("someID", sender: sender)
}
回答by Shamas S - Reinstate Monica
senderis just an argument that gets passed along with this function.
sender只是与此函数一起传递的参数。
This is received later in the function prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!), where you can get this object and make decision based on who the sender is.
这是稍后在函数中接收的prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!)，您可以在其中获取此对象并根据发件人是谁做出决定。
回答by nyxee
As an Example, suppose you want to edit something at an IndexPath. You call
例如，假设您想在IndexPath编辑某些内容。你打电话
performSegue(withIdentifier: "showItem", sender: indexPath)
performSegue(withIdentifier: "showItem", sender: indexPath)
from wherever you want (indexPathis of type IndexPathhere).
无论你想（indexPath的类型是IndexPath这里）。
Then, inside the prepare(segue:sender:), you do:
然后，在 中prepare(segue:sender:)，您执行以下操作：
...
switch segue.identifier {
case "showItem"?:
// Figure out which row was just tapped
if let row = tableView.indexPathForSelectedRow?.row {
editRow(segue, row)
} else {
let selectedIndexPath = sender as! IndexPath
editRow(segue, selectedIndexPath.row)
}
...
