Modified ios BannerExecutor to display bannerView only after bannerVi… (#337)

Co-authored-by: Masahiko Sakakibara <sakakibara@rdlabo.jp>

Author: lightning1377

ios/Sources/AdMobPlugin/Banner/BannerExecutor.swift

@@ -5,6 +5,8 @@ import GoogleMobileAds
 class BannerExecutor: NSObject, BannerViewDelegate {
     weak var plugin: AdMobPlugin?
     var bannerView: BannerView!
+    var adPosition: String = ""
+    var Margin: Int = 0
 
     func showBanner(_ call: CAPPluginCall, _ request: Request, _ adUnitID: String) {
         if let rootViewController = plugin?.getRootVC() {
@@ -109,20 +111,36 @@ class BannerExecutor: NSObject, BannerViewDelegate {
 
     private func addBannerViewToView(_ bannerView: BannerView, _ adPosition: String, _ Margin: Int) {
         removeBannerViewToView()
+        bannerView.translatesAutoresizingMaskIntoConstraints = false
+        bannerView.tag = 2743243288699 // rand
+        self.Margin = Margin
+        self.adPosition = adPosition
+    }
+
+    private func removeBannerViewToView() {
         if let rootViewController = plugin?.getRootVC() {
+            if let subView = rootViewController.view.viewWithTag(2743243288699) {
+                bannerView.delegate = nil
+                NSLog("AdMob: find subView")
+                subView.removeFromSuperview()
+            }
+        }
+    }
 
-            bannerView.translatesAutoresizingMaskIntoConstraints = false
-            bannerView.tag = 2743243288699 // rand
+    /// Tells the delegate an ad request loaded an ad.
+    func bannerViewDidReceiveAd(_ bannerView: GADBannerView) {
+        NSLog("bannerViewDidReceiveAd")
+        if let rootViewController = plugin?.getRootVC() {
             rootViewController.view.addSubview(bannerView)
             rootViewController.view.addConstraints(
                 [NSLayoutConstraint(item: bannerView,
-                                    attribute: adPosition == "TOP_CENTER" ? .top : .bottom,
+                                    attribute: self.adPosition == "TOP_CENTER" ? .top : .bottom,
                                     relatedBy: .equal,
                                     toItem: rootViewController.view.safeAreaLayoutGuide,
-                                    attribute: adPosition == "TOP_CENTER" ? .top : .bottom,
+                                    attribute: self.adPosition == "TOP_CENTER" ? .top : .bottom,
                                     multiplier: 1,
-                                    constant: CGFloat(Int(Margin) * -1)),
-                 NSLayoutConstraint(item: bannerView,
+                                    constant: CGFloat(Int(self.Margin) * -1)),
+                    NSLayoutConstraint(item: bannerView,
                                     attribute: .centerX,
                                     relatedBy: .equal,
                                     toItem: rootViewController.view,