fix crashes on android by adding null safety

android/src/main/java/com/reactnativenavigation/hierarchy/root/RootAnimator.kt

@@ -10,6 +10,10 @@ import com.reactnativenavigation.viewcontrollers.viewcontroller.ViewController
 open class RootAnimator {
 
     open fun setRoot(appearing: ViewController<*>, disappearing: ViewController<*>?, setRoot: TransitionAnimationOptions, onAnimationEnd: ()->Unit) {
+        if (appearing.isDestroyed) {
+            onAnimationEnd()
+            return
+        }
         appearing.view.visibility = View.VISIBLE
 
         if (!setRoot.hasValue() || (!setRoot.enter.hasAnimation() && !setRoot.exit.hasAnimation())) {
@@ -22,10 +26,9 @@ open class RootAnimator {
         val appearingAnimation = if (setRoot.enter.hasAnimation()) {
             setRoot.enter.getAnimation(appearing.view)
         } else null
-        val disappearingAnimation = if (disappearing != null && setRoot.exit.hasAnimation()) {
+        val disappearingAnimation = if (disappearing != null && !disappearing.isDestroyed && setRoot.exit.hasAnimation()) {
             setRoot.exit.getAnimation(disappearing.view)
         } else null
-
         when {
             appearingAnimation != null && disappearingAnimation != null -> animationSet.playTogether(appearingAnimation, disappearingAnimation)
             appearingAnimation != null -> animationSet.play(appearingAnimation)

android/src/main/java/com/reactnativenavigation/react/NavigationTurboModule.kt

@@ -84,6 +84,11 @@ class NavigationTurboModule(
         handle {
             Log.d("NavigationTurboModule", "setRoot handle ${Thread.currentThread()}")
             val viewController = layoutFactory.create(layoutTree)
+            val activity = currentActivity
+            if (activity == null) {
+                promise.reject("ACTIVITY_NULL", "Activity is null")
+                return@handle
+            }
             navigator()?.setRoot(
                 viewController,
                 NativeCommandListener("setRoot", commandId, promise, eventEmitter, now)

android/src/main/java/com/reactnativenavigation/viewcontrollers/stack/StackControllerBuilder.java

@@ -7,6 +7,7 @@
 import com.reactnativenavigation.viewcontrollers.viewcontroller.Presenter;
 import com.reactnativenavigation.react.events.EventEmitter;
 import com.reactnativenavigation.viewcontrollers.child.ChildControllersRegistry;
+import com.reactnativenavigation.NavigationApplication;
 import com.reactnativenavigation.viewcontrollers.viewcontroller.ViewController;
 import com.reactnativenavigation.viewcontrollers.stack.topbar.TopBarController;
 
@@ -32,7 +33,7 @@ public StackControllerBuilder(Activity activity, EventEmitter eventEmitter) {
         this.activity = activity;
         this.eventEmitter = eventEmitter;
         presenter = new Presenter(activity, new Options());
-        animator = new StackAnimator(activity);
+        animator = new StackAnimator(activity != null ? activity : NavigationApplication.instance);
     }
 
     public StackControllerBuilder setEventEmitter(EventEmitter eventEmitter) {

android/src/main/java/com/reactnativenavigation/viewcontrollers/viewcontroller/Presenter.java

@@ -65,7 +65,7 @@ public void onViewBroughtToFront(ViewController<?> viewController, Options optio
     }
 
     private void applyOrientation(OrientationOptions options) {
-        activity.setRequestedOrientation(options.getValue());
+        if (activity != null) activity.setRequestedOrientation(options.getValue());
     }
 
     private void applyViewOptions(ViewController view, Options options) {
@@ -127,6 +127,7 @@ private void mergeNavigationBarVisibility(NavigationBarOptions options) {
     }
 
     private void applyNavigationBarVisibility(NavigationBarOptions options) {
+        if (activity == null) return;
         View decorView = activity.getWindow().getDecorView();
         if (options.isVisible.isTrueOrUndefined()) {
             SystemUiUtils.showNavigationBar(activity.getWindow(), decorView);

android/src/main/java/com/reactnativenavigation/viewcontrollers/viewcontroller/RootPresenter.java

@@ -36,6 +36,10 @@ public RootPresenter(RootAnimator animator, LayoutDirectionApplier layoutDirecti
 
     public void setRoot(ViewController appearingRoot, ViewController<?> disappearingRoot, Options defaultOptions, CommandListener listener) {
         layoutDirectionApplier.apply(appearingRoot, defaultOptions);
+        if (appearingRoot.isDestroyed()) {
+            listener.onError("Could not set root - appearingRoot is already destroyed");
+            return;
+        }
         rootLayout.addView(appearingRoot.getView(), matchParentWithBehaviour(new BehaviourDelegate(appearingRoot)));
         Options options = appearingRoot.resolveCurrentOptions(defaultOptions);
         AnimationOptions enter = options.animations.setRoot.getEnter();
@@ -60,6 +64,10 @@ private void animateSetRootAndReportSuccess(ViewController root,
                                                 CommandListener listener,
                                                 Options options)
     {
+         if (root.isDestroyed()) {
+             listener.onError("Could not set root - root is already destroyed");
+             return;
+         }
         AnimationOptions exit = options.animations.setRoot.getExit();
         AnimationOptions enter = options.animations.setRoot.getEnter();
         if ((enter.enabled.isTrueOrUndefined() && enter.hasAnimation())
@@ -68,7 +76,9 @@ private void animateSetRootAndReportSuccess(ViewController root,
                     disappearingRoot,
                     options.animations.setRoot,
                     () -> {
-                        listener.onSuccess(root.getId());
+                        if (!root.isDestroyed()) {
+                            listener.onSuccess(root.getId());
+                        }
                         return Unit.INSTANCE;
                     });
         } else {

android/src/main/java/com/reactnativenavigation/viewcontrollers/viewcontroller/ViewController.java

@@ -235,7 +235,7 @@ public void performOnParentStack(Func1<StackController> task) {
     public T getView() {
         if (view == null) {
             if (isDestroyed) {
-                throw new RuntimeException("Tried to create view after it has already been destroyed");
+                throw new RuntimeException("Tried to create view for " + getClass().getSimpleName() + " (id: " + id + ") after it has already been destroyed");
             }
             view = createView();
             view.setOnHierarchyChangeListener(this);