fix double navigation bars at questionnaire

@@ -15,6 +15,21 @@ import SwiftEventBus
     
     public var campaignUrl: String = ""
     public var params: String = ""
+    public var showHeader: Bool = true
+
+    public override func viewWillAppear(_ animated: Bool) {
+        super.viewWillAppear(animated)
+        if (!showHeader) {
+            navigationController?.setNavigationBarHidden(true, animated: animated)
+        }
+    }
+
+    public override func viewWillDisappear(_ animated: Bool) {
+        super.viewWillDisappear(animated)
+        if (!showHeader) {
+            navigationController?.setNavigationBarHidden(false, animated: animated)
+        }
+    }
     
     public override func viewDidLoad() {
         super.viewDidLoad()
@@ -24,7 +39,9 @@ import SwiftEventBus
         
         self.hidesBottomBarWhenPushed = true
 
+        if (showHeader) {
             setBackButton()
+        }
         
         webview.navigationDelegate = self
         if let url = URL(string: campaignUrl ?? "") {

@@ -3143,6 +3143,7 @@ public class swiftApi {
                 let params = swiftApi().constructCampaignParams(item)
                 vc.campaignUrl = url
                 vc.params = params
+                vc.showHeader = false
                 controller.navigationController?.pushViewController(vc, animated: true)
                 break;
             }