destroy TitleBar component in titleBar.clear

lib/android/app/src/main/java/com/reactnativenavigation/parse/TitleOptions.java

         options.component = TextParser.parse(json, "component");
         options.alignment = Alignment.fromString(TextParser.parse(json, "alignment").get(""));
 
-        if (options.component.hasValue() && options.text.hasValue()) {
-            if (BuildConfig.DEBUG) Log.w("RNN", "A screen can't use both text and component - clearing text.");
-            options.text = new NullText();
-        }
+        validate(options);
 
         return options;
     }
         if (other.fontFamily != null) fontFamily = other.fontFamily;
         if (other.component.hasValue()) component = other.component;
         if (other.alignment != Alignment.Default) alignment = other.alignment;
+        validate(this);
     }
 
     void mergeWithDefault(TitleOptions defaultOptions) {
         if (fontFamily == null) fontFamily = defaultOptions.fontFamily;
         if (!component.hasValue()) component = defaultOptions.component;
         if (alignment == Alignment.Default) alignment = defaultOptions.alignment;
+        validate(this);
+    }
+
+    private static void validate(TitleOptions options) {
+        if (options.component.hasValue() && options.text.hasValue()) {
+            if (BuildConfig.DEBUG) Log.w("RNN", "A screen can't use both text and component - clearing text.");
+            options.text = new Text("");
+        }
     }
 }

lib/android/app/src/main/java/com/reactnativenavigation/viewcontrollers/TitleBarReactViewController.java

         this.reactViewCreator = reactViewCreator;
     }
 
+    public TitleBarReactViewController(TitleBarReactViewController reactViewController) {
+        super(reactViewController.getActivity(), CompatUtils.generateViewId() + "", new Options());
+        this.reactViewCreator = reactViewController.reactViewCreator;
+    }
+
     @Override
     protected TitleBarReactView createView() {
         return reactViewCreator.create(getActivity(), getId(), componentName);

lib/android/app/src/main/java/com/reactnativenavigation/views/titlebar/TitleBar.java

         setTitle(null);
         clearRightButtons();
         clearLeftButton();
+        clearComponent();
+    }
+
+    private void clearComponent() {
+        reactViewController.destroy();
+        reactViewController = new TitleBarReactViewController(reactViewController);
     }
 
     private void clearLeftButton() {

lib/android/app/src/test/java/com/reactnativenavigation/viewcontrollers/TitleBarTest.java

     private Button textButton;
     private Button customButton;
     private Map<String, TopBarButtonController> buttonControllers;
+    private TitleBarReactViewController reactViewController;
 
     @Override
     public void beforeEach() {
         final TopBarButtonCreatorMock buttonCreator = new TopBarButtonCreatorMock();
         final Activity activity = newActivity();
-        TitleBarReactViewController reactViewController = new TitleBarReactViewController(activity, new TitleBarReactViewCreatorMock());
+        reactViewController = spy(new TitleBarReactViewController(activity, new TitleBarReactViewCreatorMock()));
         createButtons();
         buttonControllers = new HashMap<>();
         uut = spy(new TitleBar(activity, buttonCreator, reactViewController, (buttonId -> {})) {
     @Test
     public void setComponent_addsComponentToTitleBar() throws Exception {
         uut.setComponent("com.rnn.CustomView", TitleOptions.Alignment.Center);
-        verify(uut, times(1)).addView(any(TitleBarReactView.class));
+        verify(uut, times(1)).addView(any(TitleBarReactView.class), any(Toolbar.LayoutParams.class));
     }
 
     @Test
         assertThat(lpCaptor.getValue().gravity == Gravity.CENTER);
     }
 
+    @Test
+    public void clear() throws Exception {
+        uut.clear();
+        assertThat(uut.getTitle()).isNullOrEmpty();
+        assertThat(uut.getMenu().size()).isZero();
+        assertThat(uut.getNavigationIcon()).isNull();
+        verify(reactViewController, times(1)).destroy();
+    }
+
     private List<Button> leftButton(Button leftButton) {
         return Collections.singletonList(leftButton);
     }

playground/src/screens/OptionsScreen.js

           color: 'black',
           fontSize: 16,
           fontFamily: 'HelveticaNeue-Italic',
-          largeTitle: false,
-          component: 'navigation.playground.CustomTopBar',
-          alignment: 'center'
+          largeTitle: false
         },
         ...Platform.select({
           android: { drawBehind: true },
       topBar: {
         title: {
           component: 'navigation.playground.CustomTopBar',
-          alignment: 'fill'
+          alignment: 'center'
         }
       }
     });