停止更新位置當我拖動地圖視圖

Question

我有一個mapview，他的更新位置。所以如果我搬家，我的住處不斷更新。 我想要它停止，如果我拖動地圖，並嘗試看到它的另一件事。 我該怎麼做？

我試過這個解決方案，來檢測地圖拖動時： Determine if MKMapView was dragged/moved in Swift 2.0

我在swift3工作。

1：添加手勢識別在viewDidLoad中：

let mapDragRecognizer = UIPanGestureRecognizer(target: self, action: Selector(("didDragMap:"))) 
    mapDragRecognizer.delegate = self 
    self.map.addGestureRecognizer(mapDragRecognizer) 

2：協議UIGestureRecognizerDelegate添加到視圖控制器，以便它可以作爲代表。

class MapViewController: UIViewController, UIGestureRecognizerDelegate 

將此添加其他代碼：

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool { 
return true 
} 

    func didDragMap(gestureRecognizer: UIGestureRecognizer) { 
if (gestureRecognizer.state == UIGestureRecognizerState.began) { 
    print("Map drag began") 
    self.locationManager.stopUpdatingLocation() 
    } 

if (gestureRecognizer.state == UIGestureRecognizerState.ended) { 
    print("Map drag ended") 
} 
} 

應用崩潰，如果我拖動地圖。我得到這個： 「終止應用程序由於未捕獲異常'NSInvalidArgumentException'，原因：' - [app.ViewController didDragMap：]：無法識別的選擇發送到實例0x7fdf1fd132c0'」（..）「libC++ abi.dylib：終止同類型NSException」

Answer 1

選擇語法斯威夫特3.改變了未捕獲的異常你的手勢識別，現在應該是這樣的：

let mapDragRecognizer = UIPanGestureRecognizer(target: self, action: #selector(didDragMap)) 

func didDragMap(_ gestureRecognizer: UIGestureRecognizer) { 
    if (gestureRecognizer.state == UIGestureRecognizerState.began) { 
     print("Map drag began") 
     self.locationManager.stopUpdatingLocation() 
    } 
    if (gestureRecognizer.state == UIGestureRecognizerState.ended) { 
     print("Map drag ended") 
    } 
} 

注意didDragMap(_:)根據新Swift API Design Guidelines

我宣佈也將取代您的if聲明與switch聲明，因爲一旦有兩種以上的情況，編譯器能夠更好地優化它，並且更清楚。即

func didDragMap(_ gestureRecognizer: UIGestureRecognizer) { 
    switch gestureRecognizer.state { 
    case .began: 
     print("Map drag began") 
     self.locationManager.stopUpdatingLocation() 

    case .ended: 
     print("Map drag ended") 

    default: 
     break 
    } 
}