Question

所以我有两个viewcontrollers，它们同时显示。目标如下：当我按下菜单时，它会返回一个索引。这将通知另一个屏幕需要更新。

我正在做以下事情：

控制器A（菜单）

   func carbonTabSwipeNavigation(carbonTabSwipeNavigation: CarbonTabSwipeNavigation, didMoveAtIndex index: UInt) {
    //NSLog("Did move at index: %ld", index)
        //NSNotification to send data
        NSNotificationCenter.defaultCenter().postNotificationName(NotificationNames.GetIndexCarbonKit, object: nil, userInfo: ["clickedIndex" : Int(index)])
}

控制器B（接收器）

override func viewWillAppear(animated: Bool) {
    NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(SearchResults.didReceiveNotification(_:)), name: NotificationNames.GetIndexCarbonKit, object: nil)
}


func didReceiveNotification(notification: NSNotification) {
    let index:Dictionary<String,Int> = notification.userInfo as! Dictionary<String,Int>
    let messageFromNotification = index["clickedIndex"]
    print(" SearchResults now shows index: \(messageFromNotification)")
}

我的问题如下：我将索引从A发送到B的字典，保持堆叠。因此，如果我多次按菜单，我的输出如下：

 SearchResults now shows index: Optional(0)
 SearchResults now shows index: Optional(1)
 SearchResults now shows index: Optional(1)
 SearchResults now shows index: Optional(2)
 SearchResults now shows index: Optional(2)
 SearchResults now shows index: Optional(2)
 SearchResults now shows index: Optional(3)
 SearchResults now shows index: Optional(3)
 SearchResults now shows index: Optional(3)
 SearchResults now shows index: Optional(3)
 SearchResults now shows index: Optional(1)
 SearchResults now shows index: Optional(1)
 SearchResults now shows index: Optional(1)
 SearchResults now shows index: Optional(1)
 SearchResults now shows index: Optional(1)

我怎样才能获得最后一个索引？我不需要堆叠其他人。

Answer 1

我自己找到了正确的答案。显然我只需要将NotificationCenter添加到ViewWillAppear，然后在ViewWillDisappear中将其删除。当我在视图之间切换菜单（相同视图的4倍）时，它只返回一个值。

override func viewWillAppear(animated: Bool) {
    NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(SearchResults.didReceiveNotification(_:)), name: NotificationNames.GetIndexCarbonKit, object: nil)
}

override func viewWillDisappear(animated: Bool) {
    NSNotificationCenter.defaultCenter().removeObserver(self)
}

func didReceiveNotification(notification: NSNotification) {
    let index:Dictionary<String,Int> = notification.userInfo as! Dictionary<String,Int>
    self.currentIndex = (index.first?.1)!
    print(currentIndex)
}

Answer 2

请勿在{{1}}中使用它！这是一种在ViewController中被多次调用的方法。而是在viewdidappear中使用它，只执行一次，即视图控制器加载时。你必须在

中调用它

viewDidLoad

使用功能后：

func didReceiveNotification(notification: NSNotification)

Answer 3

字典实际上是堆叠还是只是控制台窗口输出？每次按下菜单按钮后，请尝试清除控制台窗口，以查看最新情况。索引的作用域是该函数，因此一旦该函数完成，它就会消失。

Answer 4

如果您只想要最后一次单击的索引，只需在类中声明一个变量并在该变量上设置索引，这样每次检索时都会得到最后一次单击的索引

func didReceiveNotification(notification: NSNotification) {
    let index:Dictionary<String,Int> = notification.userInfo as! Dictionary<String,Int>
    self.messageFromNotification = index["clickedIndex"]
    print(" SearchResults now shows index: \(messageFromNotification)")
}

按下按钮时，NSNotification userinfo保持堆叠

4 个答案: