scroll view attacher clean up

android/app/src/main/java/com/reactnativenavigation/views/ContentView.java

@@ -2,6 +2,7 @@ package com.reactnativenavigation.views;
 
 import android.content.Context;
 import android.os.Bundle;
+import android.view.View;
 
 import com.facebook.react.ReactInstanceManager;
 import com.facebook.react.ReactRootView;
@@ -14,20 +15,25 @@ public class ContentView extends ReactRootView {
     private final String screenId;
     private final Bundle passProps;
     private Bundle navigationParams;
-    private final ScrollDirectionListener.OnScrollChanged scrollListener;
+    private ScrollViewAttacher scrollViewAttacher;
 
     public ContentView(Context context, ScreenParams screenParams, ScrollDirectionListener.OnScrollChanged scrollListener) {
         super(context);
         this.screenId = screenParams.screenId;
         this.passProps = screenParams.passProps;
         this.navigationParams = screenParams.navigationParams;
-        this.scrollListener = scrollListener;
+        scrollViewAttacher = new ScrollViewAttacher(scrollListener);
     }
 
     public void init() {
         ReactInstanceManager react = NavigationApplication.instance.getNavigationReactInstance().getReactInstanceManager();
         startReactApplication(react, screenId, mergePropsAndNavigationParams());
-        new ScrollViewAttacher(this, scrollListener).attach();
+    }
+
+    @Override
+    public void onViewAdded(View child) {
+        super.onViewAdded(child);
+        scrollViewAttacher.onViewAdded(child);
     }
 
     private Bundle mergePropsAndNavigationParams() {

android/app/src/main/java/com/reactnativenavigation/views/ScrollViewAttacher.java

@@ -1,74 +1,32 @@
 package com.reactnativenavigation.views;
 
-import android.util.Log;
 import android.view.View;
-import android.view.ViewGroup;
 import android.widget.ScrollView;
 
-import com.reactnativenavigation.utils.ViewUtils;
+public class ScrollViewAttacher {
 
-public class ScrollViewAttacher implements View.OnAttachStateChangeListener {
-
-    private final ContentView view;
     private final ScrollDirectionListener.OnScrollChanged onChanged;
     private ScrollView scrollView;
     private ScrollDirectionListener scrollDirectionListener;
 
-    public ScrollViewAttacher(ContentView view, ScrollDirectionListener.OnScrollChanged onChanged) {
-        this.view = view;
+    public ScrollViewAttacher(ScrollDirectionListener.OnScrollChanged onChanged) {
         this.onChanged = onChanged;
     }
 
-    public void attach() {
-        ViewUtils.runOnPreDraw(view, new Runnable() {
-            @Override
-            public void run() {
-                findScrollAndStartListening();
-            }
-        });
+    public void onViewAdded(View child) {
+        if (child instanceof ScrollView) {
+            detach();
+            scrollView = (ScrollView) child;
+            scrollDirectionListener = new ScrollDirectionListener(scrollView, onChanged);
+            scrollView.getViewTreeObserver().addOnScrollChangedListener(scrollDirectionListener);
+        }
     }
 
     public void detach() {
         if (scrollView != null) {
-            scrollView.removeOnAttachStateChangeListener(this);
             scrollView.getViewTreeObserver().removeOnScrollChangedListener(scrollDirectionListener);
             scrollDirectionListener = null;
             scrollView = null;
         }
     }
-
-    private void findScrollAndStartListening() {
-        scrollView = findScrollView(view);
-        Log.d("LOG", "ScrollViewAttacher.findScrollAndStartListening " + scrollView);
-        if (scrollView != null) {
-            scrollDirectionListener = new ScrollDirectionListener(scrollView, onChanged);
-            scrollView.getViewTreeObserver().addOnScrollChangedListener(scrollDirectionListener);
-            scrollView.addOnAttachStateChangeListener(this);
-        }
-    }
-
-    private ScrollView findScrollView(ViewGroup parent) {
-        for (int i = 0; i < parent.getChildCount(); i++) {
-            View child = parent.getChildAt(i);
-
-            if (child instanceof ScrollView) {
-                return (ScrollView) child;
-            } else if (child instanceof ViewGroup) {
-                return findScrollView((ViewGroup) child);
-            }
-        }
-
-        return null;
-    }
-
-    @Override
-    public void onViewAttachedToWindow(View v) {
-        // nothing
-    }
-
-    @Override
-    public void onViewDetachedFromWindow(View v) {
-        detach();
-        attach();
-    }
 }