More work towards collapsing react view in top bar

This commit contains various fixes and enhancements, mostly because I
was too lazy to commit small changes.

* Add topBarCollapseOnScroll style property which compliments
  navBarHideOnScroll. This property is needed when showing a
  collapsing topTabs screen. In this case the developer might to keep
  the titleBar bar when the screen is collapsed.
* Reduce collapse sensitivity by taking scaled touch slop into account
* Cancel touches when collapsing. This fix prevents buttons from
  responding to touch events when collapse ends.

android/app/src/main/java/com/reactnativenavigation/params/StyleParams.java

 
     public Color topBarColor;
     public CollapsingTopBarParams collapsingTopBarParams;
+    public boolean topBarCollapseOnScroll;
     public boolean topBarHidden;
     public boolean topBarElevationShadowEnabled;
     public boolean topTabsHidden;

android/app/src/main/java/com/reactnativenavigation/params/parsers/CollapsingTopBarParamsParser.java

 
     public CollapsingTopBarParams parse() {
         if (!validateParams()) {
-            return null;
+            return new CollapsingTopBarParams();
         }
         CollapsingTopBarParams result = new CollapsingTopBarParams();
         result.imageUri = params.getString("collapsingToolBarImage", null);

android/app/src/main/java/com/reactnativenavigation/params/parsers/StyleParamsParser.java

         result.topBarColor = getColor("topBarColor", getDefaultTopBarColor());
         result.titleBarHideOnScroll = getBoolean("titleBarHideOnScroll", getDefaultTitleBarHideOnScroll());
         result.topBarTransparent = getBoolean("topBarTransparent", getDefaultTopBarHidden());
+        result.topBarCollapseOnScroll = getBoolean("topBarCollapseOnScroll", false);
         result.drawScreenBelowTopBar = params.getBoolean("drawBelowTopBar", getDefaultScreenBelowTopBar());
         if (result.topBarTransparent) {
             result.drawScreenBelowTopBar = false;

android/app/src/main/java/com/reactnativenavigation/screens/CollapsingSingleScreen.java

 package com.reactnativenavigation.screens;
 
 import android.support.v7.app.AppCompatActivity;
+import android.view.MotionEvent;
 import android.widget.ScrollView;
 
+import com.facebook.react.uimanager.RootViewUtil;
 import com.reactnativenavigation.params.ScreenParams;
 import com.reactnativenavigation.views.CollapsingContentView;
 import com.reactnativenavigation.views.LeftButtonOnClickListener;
 
     @Override
     protected TopBar createTopBar() {
-        final CollapsingTopBar topBar = new CollapsingTopBar(getContext(), styleParams.collapsingTopBarParams);
+        final CollapsingTopBar topBar = new CollapsingTopBar(getContext(), styleParams);
         topBar.setScrollListener(getScrollListener(topBar));
         return topBar;
     }
         return new ScrollListener(new CollapseCalculator(topBar, getCollapseBehaviour()),
                 new OnScrollListener() {
                     @Override
-                    public void onScroll(CollapseAmount amount) {
+                    public void onScroll(MotionEvent event, CollapseAmount amount) {
                         if (screenParams.styleParams.drawScreenBelowTopBar) {
+                            RootViewUtil.getRootView(contentView).onChildStartedNativeGesture(event);
                             ((CollapsingView) contentView).collapse(amount);
                         }
                         topBar.collapse(amount);

android/app/src/main/java/com/reactnativenavigation/screens/CollapsingViewPagerScreen.java

 import android.content.Context;
 import android.support.v4.view.ViewPager;
 import android.support.v7.app.AppCompatActivity;
+import android.view.MotionEvent;
 import android.widget.ScrollView;
 
+import com.facebook.react.uimanager.RootViewUtil;
 import com.reactnativenavigation.events.Event;
 import com.reactnativenavigation.events.ViewPagerScreenChangedEvent;
 import com.reactnativenavigation.events.ViewPagerScreenScrollStartEvent;
 
     @Override
     protected TopBar createTopBar() {
-        final CollapsingTopBar topBar = new CollapsingTopBar(getContext(), styleParams.collapsingTopBarParams);
+        final CollapsingTopBar topBar = new CollapsingTopBar(getContext(), styleParams);
         topBar.setScrollListener(getScrollListener(topBar));
         return topBar;
     }
         return new ScrollListener(new CollapseCalculator(topBar, getCollapseBehaviour()),
                 new OnScrollListener() {
                     @Override
-                    public void onScroll(CollapseAmount amount) {
+                    public void onScroll(MotionEvent event, CollapseAmount amount) {
+                        RootViewUtil.getRootView(getCurrentPage()).onChildStartedNativeGesture(event);
                         topBar.collapse(amount);
                         ((CollapsingView) viewPager).collapse(amount);
                     }

android/app/src/main/java/com/reactnativenavigation/views/collapsingToolbar/CollapseCalculator.java

         totalCollapse += collapse;
         previousCollapseY = y;
         previousTouchEvent = MotionEvent.obtain(event);
-        return Math.abs(totalCollapse) < scaledTouchSlop ? CollapseAmount.None : new CollapseAmount(collapse);
+        final float delta = Math.abs(y - touchDownY);
+        return Math.abs(delta) < scaledTouchSlop ? CollapseAmount.None : new CollapseAmount(collapse);
     }
 
     private float calculateCollapse(float y) {

android/app/src/main/java/com/reactnativenavigation/views/collapsingToolbar/CollapsingTopBar.java

 
 import com.reactnativenavigation.params.CollapsingTopBarParams;
 import com.reactnativenavigation.params.NavigationParams;
+import com.reactnativenavigation.params.StyleParams;
 import com.reactnativenavigation.utils.ViewUtils;
 import com.reactnativenavigation.views.TitleBar;
 import com.reactnativenavigation.views.TopBar;
     private CollapsingTopBarReactHeader header;
     private ScrollListener scrollListener;
     private float finalCollapsedTranslation;
-    private CollapsingTopBarParams params;
+    private final StyleParams styleParams;
+    private final CollapsingTopBarParams params;
     private final ViewCollapser viewCollapser;
     private final int topBarHeight;
     private String title;
 
-    public CollapsingTopBar(Context context, final CollapsingTopBarParams params) {
+    public CollapsingTopBar(Context context, final StyleParams params) {
         super(context);
-        this.params = params;
+        styleParams = params;
+        this.params = params.collapsingTopBarParams;
         topBarHeight = calculateTopBarHeight();
-        createBackgroundImage(params);
-        calculateFinalCollapsedTranslation(params);
+        createBackgroundImage();
+        calculateFinalCollapsedTranslation();
         viewCollapser = new ViewCollapser(this);
     }
 
-    private void calculateFinalCollapsedTranslation(final CollapsingTopBarParams params) {
+    private void calculateFinalCollapsedTranslation() {
         ViewUtils.runOnPreDraw(this, new Runnable() {
             @Override
             public void run() {
                 if (params.hasBackgroundImage() || params.hasReactView()) {
                     finalCollapsedTranslation = getCollapsedHeight() - getHeight();
+                    if (styleParams.topBarCollapseOnScroll) {
+                        finalCollapsedTranslation += titleBar.getHeight();
+                    }
                 } else {
                     finalCollapsedTranslation = -titleBar.getHeight();
                 }
         }
     }
 
-    private void createBackgroundImage(CollapsingTopBarParams params) {
+    private void createBackgroundImage() {
         if (params.hasBackgroundImage()) {
             collapsingTopBarBackground = new CollapsingTopBarBackground(getContext(), params);
             LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT, (int) CollapsingTopBarBackground.MAX_HEIGHT);

android/app/src/main/java/com/reactnativenavigation/views/collapsingToolbar/OnScrollListener.java

 package com.reactnativenavigation.views.collapsingToolbar;
 
+import android.view.MotionEvent;
+
 public interface  OnScrollListener extends OnFlingListener {
-    void onScroll(CollapseAmount amount);
+    void onScroll(MotionEvent event, CollapseAmount amount);
 }

android/app/src/main/java/com/reactnativenavigation/views/collapsingToolbar/ScrollListener.java

     boolean onTouch(MotionEvent event) {
         CollapseAmount amount = collapseCalculator.calculate(event);
         if (amount.canCollapse()) {
-            scrollListener.onScroll(amount);
+            scrollListener.onScroll(event, amount);
             return collapseBehaviour instanceof CollapseTopBarBehaviour;
         }
         return false;

src/deprecated/platformSpecificDeprecated.android.js

     topBarTransparent: originalStyleObject.navBarTransparent,
     topBarTranslucent: originalStyleObject.navBarTranslucent,
     topBarElevationShadowEnabled: originalStyleObject.topBarElevationShadowEnabled,
+    topBarCollapseOnScroll: originalStyleObject.topBarCollapseOnScroll,
     collapsingToolBarImage: originalStyleObject.collapsingToolBarImage,
     collapsingToolBarComponent: originalStyleObject.collapsingToolBarComponent,
     collapsingToolBarComponentHeight: originalStyleObject.collapsingToolBarComponentHeight,