Add support to set gestureView manually

Author: devxoul

Sources/RxKeyboard.swift

@@ -19,6 +19,17 @@ public class RxKeyboard: NSObject {
   /// Get a singleton instance.
   public static let instance = RxKeyboard()
 
+  /// A view that receives pan gesture. The default value is the AppDelegate's window. Set this
+  /// value with the root view controller's view if the target is an App Extension.
+  public var gestureView: UIView? {
+    get { return self._gestureView ?? self.application?.delegate?.window ?? nil }
+    set {
+      self._gestureView = newValue
+      self.panRecognizer.view?.removeGestureRecognizer(self.panRecognizer)
+      newValue?.addGestureRecognizer(self.panRecognizer)
+    }
+  }
+
   /// An observable keyboard frame.
   public let frame: Driver<CGRect>
 
@@ -35,13 +46,12 @@ public class RxKeyboard: NSObject {
 
   fileprivate let disposeBag = DisposeBag()
   fileprivate let panRecognizer = UIPanGestureRecognizer()
+
   fileprivate let application: UIApplication? = {
     let selector = NSSelectorFromString("sharedApplication")
     return UIApplication.perform(selector)?.takeRetainedValue() as? UIApplication
   }()
-  fileprivate var gestureView: UIView? {
-    return self.application?.delegate?.window ?? nil
-  }
+  fileprivate var _gestureView: UIView?
 
 
   // MARK: Initializing
@@ -119,7 +129,8 @@ public class RxKeyboard: NSObject {
     NotificationCenter.default.rx.notification(.UIApplicationDidFinishLaunching)
       .map { _ in Void() }
       .startWith(Void()) // when RxKeyboard is initialized before UIApplication.window is created
-      .subscribe(onNext: { _ in
+      .subscribe(onNext: { [weak self] _ in
+        guard let `self` = self else { return }
         self.gestureView?.addGestureRecognizer(self.panRecognizer)
       })
       .addDisposableTo(self.disposeBag)