diff --git a/lib/animations/animations.dart b/lib/animations/animations.dart
index 36cc6f4f..7243f985 100644
--- a/lib/animations/animations.dart
+++ b/lib/animations/animations.dart
@@ -52,7 +52,7 @@ class _OffsetAnimationState extends State<OffsetAnimation>
   }
 
   _hideAnimation() {
-    WidgetsBinding.instance!.addPostFrameCallback((_) {
+    WidgetsBinding.instance.addPostFrameCallback((_) {
       if (_hideNavigationBar!) {
         _navBarHideAnimationController.forward();
       } else {
diff --git a/lib/nav-bar-styles/style-11-bottom-nav-bar.widget.dart b/lib/nav-bar-styles/style-11-bottom-nav-bar.widget.dart
index 14379350..c42c6857 100644
--- a/lib/nav-bar-styles/style-11-bottom-nav-bar.widget.dart
+++ b/lib/nav-bar-styles/style-11-bottom-nav-bar.widget.dart
@@ -43,7 +43,7 @@ class _BottomNavStyle11State extends State<BottomNavStyle11>
           .animate(_animationControllerList[i]));
     }
 
-    WidgetsBinding.instance!.addPostFrameCallback((_) {
+    WidgetsBinding.instance.addPostFrameCallback((_) {
       _animationControllerList[_selectedIndex!].forward();
     });
   }
diff --git a/lib/nav-bar-styles/style-12-bottom-nav-bar.widget.dart b/lib/nav-bar-styles/style-12-bottom-nav-bar.widget.dart
index f748cf99..2a2b5841 100644
--- a/lib/nav-bar-styles/style-12-bottom-nav-bar.widget.dart
+++ b/lib/nav-bar-styles/style-12-bottom-nav-bar.widget.dart
@@ -43,7 +43,7 @@ class _BottomNavStyle12State extends State<BottomNavStyle12>
           .animate(_animationControllerList[i]));
     }
 
-    WidgetsBinding.instance!.addPostFrameCallback((_) {
+    WidgetsBinding.instance.addPostFrameCallback((_) {
       _animationControllerList[_selectedIndex!].forward();
     });
   }
diff --git a/lib/nav-bar-styles/style-13-bottom-nav-bar.widget.dart b/lib/nav-bar-styles/style-13-bottom-nav-bar.widget.dart
index 344226cc..450932e7 100644
--- a/lib/nav-bar-styles/style-13-bottom-nav-bar.widget.dart
+++ b/lib/nav-bar-styles/style-13-bottom-nav-bar.widget.dart
@@ -43,7 +43,7 @@ class _BottomNavStyle13State extends State<BottomNavStyle13>
           .animate(_animationControllerList[i]));
     }
 
-    WidgetsBinding.instance!.addPostFrameCallback((_) {
+    WidgetsBinding.instance.addPostFrameCallback((_) {
       _animationControllerList[_selectedIndex!].forward();
     });
   }
diff --git a/lib/nav-bar-styles/style-14-bottom-nav-bar.widget.dart b/lib/nav-bar-styles/style-14-bottom-nav-bar.widget.dart
index 2d608b1d..d12005f7 100644
--- a/lib/nav-bar-styles/style-14-bottom-nav-bar.widget.dart
+++ b/lib/nav-bar-styles/style-14-bottom-nav-bar.widget.dart
@@ -43,7 +43,7 @@ class _BottomNavStyle14State extends State<BottomNavStyle14>
           .animate(_animationControllerList[i]));
     }
 
-    WidgetsBinding.instance!.addPostFrameCallback((_) {
+    WidgetsBinding.instance.addPostFrameCallback((_) {
       _animationControllerList[_selectedIndex!].forward();
     });
   }
diff --git a/lib/nav-bar-styles/style-6-bottom-nav-bar.widget.dart b/lib/nav-bar-styles/style-6-bottom-nav-bar.widget.dart
index 1fc1e0a3..1886392f 100644
--- a/lib/nav-bar-styles/style-6-bottom-nav-bar.widget.dart
+++ b/lib/nav-bar-styles/style-6-bottom-nav-bar.widget.dart
@@ -41,7 +41,7 @@ class _BottomNavStyle6State extends State<BottomNavStyle6>
           .animate(_animationControllerList[i]));
     }
 
-    WidgetsBinding.instance!.addPostFrameCallback((_) {
+    WidgetsBinding.instance.addPostFrameCallback((_) {
       _animationControllerList[_selectedIndex!].forward();
     });
   }
diff --git a/lib/nav-bar-styles/style-8-bottom-nav-bar.widget.dart b/lib/nav-bar-styles/style-8-bottom-nav-bar.widget.dart
index bae36f56..ed6b56de 100644
--- a/lib/nav-bar-styles/style-8-bottom-nav-bar.widget.dart
+++ b/lib/nav-bar-styles/style-8-bottom-nav-bar.widget.dart
@@ -41,7 +41,7 @@ class _BottomNavStyle8State extends State<BottomNavStyle8>
           .animate(_animationControllerList[i]));
     }
 
-    WidgetsBinding.instance!.addPostFrameCallback((_) {
+    WidgetsBinding.instance.addPostFrameCallback((_) {
       _animationControllerList[_selectedIndex!].forward();
     });
   }
diff --git a/lib/persistent-tab-view.dart b/lib/persistent-tab-view.dart
index 559cfd88..6cfe3a76 100644
--- a/lib/persistent-tab-view.dart
+++ b/lib/persistent-tab-view.dart
@@ -5,8 +5,6 @@ import 'dart:ui';
 
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter/cupertino.dart' show CupertinoApp;
-
 //Main TabView Widget
 part 'persistent-tab-view.widget.dart';
 
diff --git a/lib/persistent-tab-view.widget.dart b/lib/persistent-tab-view.widget.dart
index 9b359c62..f458d3c0 100644
--- a/lib/persistent-tab-view.widget.dart
+++ b/lib/persistent-tab-view.widget.dart
@@ -365,7 +365,7 @@ class _PersistentTabViewState extends State<PersistentTabView> {
       }
     });
     if (widget.selectedTabScreenContext != null) {
-      WidgetsBinding.instance!.addPostFrameCallback((_) {
+      WidgetsBinding.instance.addPostFrameCallback((_) {
         widget.selectedTabScreenContext!(_contextList[_controller!.index]);
       });
     }