scroll direction listener

android/app/src/main/java/com/reactnativenavigation/layouts/ScreenLayout.java

@@ -1,7 +1,17 @@
 package com.reactnativenavigation.layouts;
 
-import com.facebook.react.ReactRootView;
+import android.content.Context;
+import android.widget.LinearLayout;
 
-public class ScreenLayout extends ReactRootView {
+public class ScreenLayout extends LinearLayout {
 
+    public static class Params {
+
+    }
+
+    public ScreenLayout(Context context, Params params) {
+        super(context);
+        setOrientation(VERTICAL);
+        addView();
+    }
 }

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

@@ -0,0 +1,43 @@
+package com.reactnativenavigation.views;
+
+import android.content.Context;
+import android.os.Bundle;
+import android.support.annotation.Nullable;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ScrollView;
+
+import com.facebook.react.ReactInstanceManager;
+import com.facebook.react.ReactRootView;
+
+public class ContentView extends ReactRootView {
+
+    public ContentView(Context context, ReactInstanceManager reactInstanceManager, String moduleName, Bundle passProps) {
+        super(context);
+        startReactApplication(reactInstanceManager, moduleName, passProps);
+    }
+
+    @Nullable
+    public ScrollView findScrollView() {
+        return findScrollView(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
+    protected void onDetachedFromWindow() {
+        super.onDetachedFromWindow();
+    }
+}

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

@@ -23,26 +23,6 @@ public class RctView extends FrameLayout {
     private BottomTabActivity context;
     private ReactRootView reactRootView;
     private ScrollView scrollView;
-    private int lastScrollY = -1;
-    private final ViewTreeObserver.OnScrollChangedListener scrollChangedListener = new ViewTreeObserver.OnScrollChangedListener() {
-        @Override
-        public void onScrollChanged() {
-            if (!scrollView.getViewTreeObserver().isAlive()) {
-                return;
-            }
-
-            final int scrollY = scrollView.getScrollY();
-            if (scrollY != lastScrollY && // Scroll position changed
-                scrollY > 0 && // Ignore top overscroll
-                scrollY < (scrollView.getChildAt(0).getHeight() - scrollView.getHeight())) { // Ignore bottom overscroll
-                int direction = scrollY > lastScrollY ?
-                        BottomNavigation.SCROLL_DIRECTION_DOWN :
-                        BottomNavigation.SCROLL_DIRECTION_UP;
-                lastScrollY = scrollY;
-                context.onScrollChanged(direction);
-            }
-        }
-    };
     private boolean isScrollEventListenerRegistered = false;
 
     private final View.OnAttachStateChangeListener stateChangeListener =
@@ -90,16 +70,16 @@ public class RctView extends FrameLayout {
         setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
 
         final OnDisplayedListener onDisplayedListenerInternal = screen.bottomTabsHiddenOnScroll ?
-            new OnDisplayedListener() {
-                @Override
-                public void onDisplayed() {
-                    if (onDisplayedListener != null) {
-                        onDisplayedListener.onDisplayed();
-                    }
+                new OnDisplayedListener() {
+                    @Override
+                    public void onDisplayed() {
+                        if (onDisplayedListener != null) {
+                            onDisplayedListener.onDisplayed();
+                        }
 
-                    setupScrollViewWithBottomTabs();
-                }
-            } : onDisplayedListener;
+                        setupScrollViewWithBottomTabs();
+                    }
+                } : onDisplayedListener;
 
         reactRootView = new RnnReactRootView(ctx, onDisplayedListenerInternal);
         reactRootView.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
@@ -130,21 +110,6 @@ public class RctView extends FrameLayout {
         }
     }
 
-    private ScrollView getScrollView(ViewGroup parent) {
-        for (int i = 0; i < parent.getChildCount(); i++) {
-            View child = parent.getChildAt(i);
-
-            if (child instanceof ScrollView) {
-                return (ScrollView) child;
-            }
-
-            if (child instanceof ViewGroup) {
-                return getScrollView((ViewGroup) child);
-            }
-        }
-
-        return null;
-    }
 
     private void attachStateChangeListener(ScrollView scrollView) {
         scrollView.addOnAttachStateChangeListener(stateChangeListener);

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

@@ -0,0 +1,49 @@
+package com.reactnativenavigation.views;
+
+import android.view.ViewGroup;
+import android.view.ViewTreeObserver;
+
+public class ScrollDirectionListener implements ViewTreeObserver.OnScrollChangedListener {
+    public enum Direction {
+        Up, Down
+    }
+
+    public interface OnChanged {
+        void onChanged(Direction direction);
+    }
+
+    private final ViewGroup view;
+    private final OnChanged onChanged;
+    private int lastScrollY = -1;
+
+    public ScrollDirectionListener(ViewGroup view, OnChanged onChanged) {
+        this.view = view;
+        this.onChanged = onChanged;
+    }
+
+    @Override
+    public void onScrollChanged() {
+        if (!view.getViewTreeObserver().isAlive()) {
+            return;
+        }
+
+        final int scrollY = view.getScrollY();
+        if (isScrollPositionChanged(scrollY) && !isTopOverscroll(scrollY) && !isBottomOverscroll(scrollY)) {
+            lastScrollY = scrollY;
+            onChanged.onChanged(scrollY > lastScrollY ? Direction.Down : Direction.Up);
+        }
+    }
+
+    private boolean isBottomOverscroll(int scrollY) {
+        return scrollY >= (view.getChildAt(0).getHeight() - view.getHeight());
+    }
+
+    private boolean isTopOverscroll(int scrollY) {
+        return scrollY <= 0;
+    }
+
+    private boolean isScrollPositionChanged(int scrollY) {
+        return scrollY != lastScrollY;
+    }
+
+}