Pull EventDispatcher to Application scope (#2508)

Application class can now be accessed statically using Context to access AppModule
which provides dependencies needed throughout the app.

lib/android/app/src/main/java/com/reactnativenavigation/anim/TopBarAnimator.java

 public class TopBarAnimator {
 
     private static final int DURATION_TOPBAR = 300;
-    private DecelerateInterpolator decelerateInterpolator;
-    private AccelerateInterpolator accelerateInterpolator;
+    private final DecelerateInterpolator decelerateInterpolator = new DecelerateInterpolator();
+    private final AccelerateInterpolator accelerateInterpolator = new AccelerateInterpolator();
 
     private TopBar topBar;
     private View contentView;
 
+    public TopBarAnimator(TopBar topBar) {
+        this.topBar = topBar;
+    }
+
     public TopBarAnimator(TopBar topBar, View contentView) {
-        decelerateInterpolator = new DecelerateInterpolator();
-        accelerateInterpolator = new AccelerateInterpolator();
         this.topBar = topBar;
         this.contentView = contentView;
     }
         hide(0, accelerateInterpolator, DURATION_TOPBAR);
     }
 
-    public void hide(float startTranslation, TimeInterpolator interpolator, int duration) {
+    void hide(float startTranslation, TimeInterpolator interpolator, int duration) {
         ObjectAnimator topbarAnim = ObjectAnimator.ofFloat(topBar, View.TRANSLATION_Y, startTranslation, -1 * topBar.getMeasuredHeight());
         topbarAnim.setInterpolator(interpolator);
         topbarAnim.setDuration(duration);

lib/android/app/src/main/java/com/reactnativenavigation/anim/TopBarCollapseBehavior.java

 
 import android.view.View;
 
-import com.facebook.react.uimanager.events.EventDispatcher;
 import com.reactnativenavigation.interfaces.ScrollEventListener;
-import com.reactnativenavigation.utils.UiThread;
 import com.reactnativenavigation.views.TopBar;
 
-public class TopBarCollapseBehavior {
+public class TopBarCollapseBehavior implements ScrollEventListener.OnScrollListener, ScrollEventListener.OnDragListener {
     private TopBar topBar;
-
-    private EventDispatcher eventDispatcher;
     private ScrollEventListener scrollEventListener;
-    private boolean dragStarted;
     private TopBarAnimator animator;
 
-    public TopBarCollapseBehavior(EventDispatcher eventDispatcher, TopBar topBar) {
-        this.eventDispatcher = eventDispatcher;
+    public TopBarCollapseBehavior(TopBar topBar, ScrollEventListener scrollEventListener) {
         this.topBar = topBar;
-        this.animator = new TopBarAnimator(topBar, null);
+        this.animator = new TopBarAnimator(topBar);
+        this.scrollEventListener = scrollEventListener;
     }
 
     public void enableCollapse() {
-        scrollEventListener = (new ScrollEventListener(new ScrollEventListener.OnVerticalScrollListener() {
-            @Override
-            public void onVerticalScroll(int scrollY, int oldScrollY) {
-                if (scrollY < 0) return;
-                if (!dragStarted) return;
-
-                final int scrollDiff = calcScrollDiff(scrollY, oldScrollY, topBar.getMeasuredHeight());
-                final float nextTranslation = topBar.getTranslationY() - scrollDiff;
-                if (scrollDiff < 0) {
-                    down(topBar.getMeasuredHeight(), nextTranslation);
-                } else {
-                    up(topBar.getMeasuredHeight(), nextTranslation);
-                }
-            }
+        scrollEventListener.register(topBar, this, this);
+    }
 
-            @Override
-            public void onDrag(boolean started, double velocity) {
-                dragStarted = started;
-                UiThread.post(() -> {
-                    if (!dragStarted) {
-                        if (velocity > 0) {
-                            animator.show(topBar.getTranslationY(), null, 100);
-                        } else {
-                            animator.hide(topBar.getTranslationY(), null, 100);
-                        }
-                    }
-                });
-            }
-        }));
-        if (eventDispatcher != null) {
-            eventDispatcher.addListener(scrollEventListener);
-        }
+    public void disableCollapse() {
+        scrollEventListener.unregister();
+        topBar.setVisibility(View.VISIBLE);
+        topBar.setTranslationY(0);
     }
 
-    private void up(int measuredHeight, float nextTranslation) {
+    @Override
+    public void onScrollUp(float nextTranslation) {
+        final int measuredHeight = topBar.getMeasuredHeight();
         if (nextTranslation < -measuredHeight && topBar.getVisibility() == View.VISIBLE) {
             topBar.setVisibility(View.GONE);
             topBar.setTranslationY(-measuredHeight);
         }
     }
 
-    private void down(int measuredHeight, float nextTranslation) {
+    @Override
+    public void onScrollDown(float nextTranslation) {
+        final int measuredHeight = topBar.getMeasuredHeight();
         if (topBar.getVisibility() == View.GONE && nextTranslation > -measuredHeight) {
             topBar.setVisibility(View.VISIBLE);
             topBar.setTranslationY(nextTranslation);
         }
     }
 
-    private int calcScrollDiff(int scrollY, int oldScrollY, int measuredHeight) {
-        int diff = scrollY - oldScrollY;
-        if (Math.abs(diff) > measuredHeight) {
-            diff = (Math.abs(diff) / diff) * measuredHeight;
-        }
-        return diff;
+    @Override
+    public void onShow() {
+        animator.show(topBar.getTranslationY(), null, 100);
     }
 
-    public void disableCollapse() {
-        if (eventDispatcher != null) {
-            eventDispatcher.removeListener(scrollEventListener);
-        }
-        topBar.setVisibility(View.VISIBLE);
-        topBar.setTranslationY(0);
+    @Override
+    public void onHide() {
+        animator.hide(topBar.getTranslationY(), null, 100);
     }
 }

lib/android/app/src/main/java/com/reactnativenavigation/interfaces/ScrollEventListener.java

 package com.reactnativenavigation.interfaces;
 
 import com.facebook.react.uimanager.events.Event;
+import com.facebook.react.uimanager.events.EventDispatcher;
 import com.facebook.react.uimanager.events.EventDispatcherListener;
 import com.facebook.react.views.scroll.ScrollEvent;
 import com.reactnativenavigation.utils.ReflectionUtils;
+import com.reactnativenavigation.utils.UiThread;
 
 public class ScrollEventListener implements EventDispatcherListener {
 
-    private OnVerticalScrollListener verticalScrollListener;
+    public interface OnScrollListener {
+        void onScrollUp(float nextTranslation);
+
+        void onScrollDown(float nextTranslation);
+    }
+
+    public interface OnDragListener {
+        void onShow();
+
+        void onHide();
+    }
+
+    public interface ScrollAwareView {
+        int getMeasuredHeight();
+
+        float getTranslationY();
+    }
+
+    private ScrollAwareView view;
+    private OnScrollListener onScrollListener;
+    private OnDragListener dragListener;
+    private EventDispatcher eventDispatcher;
     private int prevScrollY = -1;
+    private boolean dragStarted;
 
-    public interface OnVerticalScrollListener {
-        void onVerticalScroll(int scrollY, int oldScrollY);
+    public ScrollEventListener(EventDispatcher eventDispatcher) {
+        this.eventDispatcher = eventDispatcher;
+    }
 
-        void onDrag(boolean started, double velocity);
+    public void register(ScrollAwareView scrollAwareView, OnScrollListener scrollListener, OnDragListener dragListener) {
+        this.view = scrollAwareView;
+        this.onScrollListener = scrollListener;
+        this.dragListener = dragListener;
+        eventDispatcher.addListener(this);
     }
 
-    public ScrollEventListener(OnVerticalScrollListener verticalScrollListener) {
-        this.verticalScrollListener = verticalScrollListener;
+    public void unregister() {
+        eventDispatcher.removeListener(this);
     }
 
     @Override
         try {
             if ("topScroll".equals(event.getEventName())) {
                 int scrollY = (int) ReflectionUtils.getDeclaredField(event, "mScrollY");
-                verticalScrollListener.onVerticalScroll(scrollY, prevScrollY);
+                onVerticalScroll(scrollY, prevScrollY);
                 if (scrollY != prevScrollY) {
                     prevScrollY = scrollY;
                 }
             } else if ("topScrollBeginDrag".equals(event.getEventName())) {
                 double velocity = (double) ReflectionUtils.getDeclaredField(event, "mYVelocity");
-                verticalScrollListener.onDrag(true, velocity);
+                onDrag(true, velocity);
             } else if ("topScrollEndDrag".equals(event.getEventName())) {
                 double velocity = (double) ReflectionUtils.getDeclaredField(event, "mYVelocity");
-                verticalScrollListener.onDrag(false, velocity);
+                onDrag(false, velocity);
             }
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
+
+    private void onVerticalScroll(int scrollY, int oldScrollY) {
+        if (scrollY < 0) return;
+        if (!dragStarted) return;
+
+        final int scrollDiff = calcScrollDiff(scrollY, oldScrollY, view.getMeasuredHeight());
+        final float translationY = view.getTranslationY() - scrollDiff;
+        if (scrollDiff < 0) {
+            onScrollListener.onScrollDown(translationY);
+        } else {
+            onScrollListener.onScrollUp(translationY);
+        }
+    }
+
+    private int calcScrollDiff(int scrollY, int oldScrollY, int measuredHeight) {
+        int diff = scrollY - oldScrollY;
+        if (Math.abs(diff) > measuredHeight) {
+            diff = (Math.abs(diff) / diff) * measuredHeight;
+        }
+        return diff;
+    }
+
+    private void onDrag(boolean started, double velocity) {
+        dragStarted = started;
+        UiThread.post(() -> {
+            if (!dragStarted) {
+                if (velocity > 0) {
+                    dragListener.onShow();
+                } else {
+                    dragListener.onHide();
+                }
+            }
+        });
+    }
 }

lib/android/app/src/main/java/com/reactnativenavigation/react/ReactView.java

 
 import com.facebook.react.ReactInstanceManager;
 import com.facebook.react.ReactRootView;
+import com.facebook.react.bridge.ReactContext;
+import com.facebook.react.uimanager.UIManagerModule;
+import com.facebook.react.uimanager.events.EventDispatcher;
+import com.reactnativenavigation.interfaces.ScrollEventListener;
 import com.reactnativenavigation.viewcontrollers.ComponentViewController;
 
 @SuppressLint("ViewConstructor")
 	public void sendOnNavigationButtonPressed(String buttonId) {
 		new NavigationEvent(reactInstanceManager.getCurrentReactContext()).sendOnNavigationButtonPressed(componentId, buttonId);
 	}
+
+    @Override
+    public ScrollEventListener getScrollEventListener() {
+        return new ScrollEventListener(getEventDispatcher());
+    }
+
+    public EventDispatcher getEventDispatcher() {
+        ReactContext reactContext = reactInstanceManager.getCurrentReactContext();
+        return reactContext == null ? null : reactContext.getNativeModule(UIManagerModule.class).getEventDispatcher();
+    }
 }

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

 import android.support.annotation.*;
 import android.view.*;
 
+import com.reactnativenavigation.interfaces.ScrollEventListener;
 import com.reactnativenavigation.parse.*;
 import com.reactnativenavigation.presentation.*;
 import com.reactnativenavigation.views.*;
         void sendComponentStop();
 
         void sendOnNavigationButtonPressed(String buttonId);
+
+        ScrollEventListener getScrollEventListener();
     }
 
     private final String componentName;

lib/android/app/src/main/java/com/reactnativenavigation/views/ComponentLayout.java

 package com.reactnativenavigation.views;
 
-import android.annotation.*;
-import android.content.*;
-import android.view.*;
-import android.widget.*;
+import android.annotation.SuppressLint;
+import android.content.Context;
+import android.view.View;
+import android.widget.RelativeLayout;
 
-import com.facebook.react.uimanager.events.*;
-import com.reactnativenavigation.parse.*;
-import com.reactnativenavigation.presentation.*;
-import com.reactnativenavigation.viewcontrollers.ComponentViewController.*;
+import com.reactnativenavigation.interfaces.ScrollEventListener;
+import com.reactnativenavigation.parse.Options;
+import com.reactnativenavigation.presentation.OptionsPresenter;
+import com.reactnativenavigation.viewcontrollers.ComponentViewController.IReactView;
 
-import static android.view.ViewGroup.LayoutParams.*;
+import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
+import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT;
 
 @SuppressLint("ViewConstructor")
 public class ComponentLayout extends RelativeLayout implements ReactComponent, TitleBarButton.OnClickListener {
     private IReactView reactView;
     private final OptionsPresenter optionsPresenter;
 
-	public ComponentLayout(Context context, IReactView reactView, EventDispatcher eventDispatcher) {
+	public ComponentLayout(Context context, IReactView reactView) {
 		super(context);
 		this.reactView = reactView;
-		this.topBar = new TopBar(context, reactView.asView(), this, eventDispatcher);
+		this.topBar = new TopBar(context, reactView.asView(), reactView.getScrollEventListener(), this);
         optionsPresenter = new OptionsPresenter(this);
         initViews();
     }
         reactView.sendOnNavigationButtonPressed(buttonId);
     }
 
+    @Override
+    public ScrollEventListener getScrollEventListener() {
+        return reactView.getScrollEventListener();
+    }
+
     @Override
     public TopBar getTopBar() {
         return topBar;

lib/android/app/src/main/java/com/reactnativenavigation/views/ComponentViewCreator.java

 package com.reactnativenavigation.views;
 
-import android.app.*;
+import android.app.Activity;
 
-import com.facebook.react.*;
-import com.facebook.react.uimanager.*;
-import com.reactnativenavigation.react.*;
-import com.reactnativenavigation.viewcontrollers.*;
+import com.facebook.react.ReactInstanceManager;
+import com.reactnativenavigation.react.ReactComponentViewCreator;
+import com.reactnativenavigation.viewcontrollers.ComponentViewController;
 
 public class ComponentViewCreator implements ComponentViewController.ReactViewCreator {
 
 	@Override
 	public ComponentViewController.IReactView create(Activity activity, String componentId, String componentName) {
         ComponentViewController.IReactView reactView = new ReactComponentViewCreator(instanceManager).create(activity, componentId, componentName);
-        return new ComponentLayout(activity, reactView, instanceManager.getCurrentReactContext().getNativeModule(UIManagerModule.class).getEventDispatcher());
+        return new ComponentLayout(activity, reactView);
 	}
 }

lib/android/app/src/main/java/com/reactnativenavigation/views/TopBar.java

 import android.view.ViewGroup;
 import android.widget.TextView;
 
-import com.facebook.react.uimanager.events.EventDispatcher;
 import com.reactnativenavigation.anim.TopBarAnimator;
 import com.reactnativenavigation.anim.TopBarCollapseBehavior;
+import com.reactnativenavigation.interfaces.ScrollEventListener;
 import com.reactnativenavigation.parse.Button;
 import com.reactnativenavigation.parse.Color;
 import com.reactnativenavigation.parse.Number;
 import java.util.ArrayList;
 
 @SuppressLint("ViewConstructor")
-public class TopBar extends AppBarLayout {
+public class TopBar extends AppBarLayout implements ScrollEventListener.ScrollAwareView {
     private final Toolbar titleBar;
     private TitleBarButton.OnClickListener onClickListener;
     private final TopBarCollapseBehavior collapsingBehavior;
     private final TopBarAnimator animator;
     private TopTabs topTabs;
 
-    public TopBar(final Context context, View contentView, TitleBarButton.OnClickListener onClickListener, EventDispatcher eventDispatcher) {
+    public TopBar(final Context context, View contentView, ScrollEventListener scrollEventListener, TitleBarButton.OnClickListener onClickListener) {
         super(context);
         this.onClickListener = onClickListener;
-        collapsingBehavior = new TopBarCollapseBehavior(eventDispatcher, this);
+        collapsingBehavior = new TopBarCollapseBehavior(this, scrollEventListener);
         titleBar = new Toolbar(context);
         topTabs = new TopTabs(getContext());
         this.animator = new TopBarAnimator(this, contentView);

lib/android/app/src/main/java/com/reactnativenavigation/views/TopTab.java

 import android.view.View;
 import android.widget.FrameLayout;
 
+import com.reactnativenavigation.interfaces.ScrollEventListener;
 import com.reactnativenavigation.viewcontrollers.ComponentViewController.IReactView;
 
 @SuppressLint("ViewConstructor")
     public void sendOnNavigationButtonPressed(String buttonId) {
         reactView.sendOnNavigationButtonPressed(buttonId);
     }
+
+    @Override
+    public ScrollEventListener getScrollEventListener() {
+        return reactView.getScrollEventListener();
+    }
 }

lib/android/app/src/main/java/com/reactnativenavigation/views/TopTabsLayout.java

         super(context);
         this.tabs = tabs;
         viewPager = new TopTabsViewPager(context, tabs, adapter);
-        topBar = new TopBar(context, viewPager, this, null);
+        topBar = new TopBar(context, viewPager, null, this);
         topBar.setId(View.generateViewId());
         optionsPresenter = new OptionsPresenter(this);
         initViews();

lib/android/app/src/test/java/com/reactnativenavigation/mocks/TestComponentLayout.java

 import android.view.*;
 import android.widget.*;
 
+import com.reactnativenavigation.interfaces.ScrollEventListener;
 import com.reactnativenavigation.parse.*;
 import com.reactnativenavigation.presentation.*;
 import com.reactnativenavigation.views.*;
     public TestComponentLayout(final Context context) {
         super(context);
         contentView = new View(context);
-        topBar = new TopBar(context, contentView, this, null);
+        topBar = new TopBar(context, contentView, null, this);
         addView(topBar);
         addView(contentView);
         optionsPresenter = new OptionsPresenter(this);
 
     }
 
+    @Override
+    public ScrollEventListener getScrollEventListener() {
+        return null;
+    }
+
     @Override
     public void onPress(String buttonId) {
 

lib/android/app/src/test/java/com/reactnativenavigation/mocks/TestComponentView.java

-package com.reactnativenavigation.mocks;
-
-import android.content.*;
-import android.view.*;
-
-import com.reactnativenavigation.parse.*;
-import com.reactnativenavigation.views.*;
-
-public class TestComponentView extends View implements ReactComponent, TitleBarButton.OnClickListener {
-
-    private TopBar topBar;
-
-    public TestComponentView(final Context context) {
-        super(context);
-        topBar = new TopBar(context, this, this, null);
-
-    }
-
-    @Override
-    public boolean isReady() {
-        return false;
-    }
-
-    @Override
-    public View asView() {
-        return this;
-    }
-
-    @Override
-    public void destroy() {
-    }
-
-    @Override
-    public void sendComponentStart() {
-    }
-
-    @Override
-    public void sendComponentStop() {
-    }
-
-    @Override
-    public void applyOptions(Options options) {
-
-    }
-
-    @Override
-    public void sendOnNavigationButtonPressed(String id) {
-
-    }
-
-    @Override
-    public TopBar getTopBar() {
-        return topBar;
-    }
-
-    @Override
-    public void drawBehindTopBar() {
-
-    }
-
-    @Override
-    public void drawBelowTopBar() {
-
-    }
-
-    @Override
-    public void onPress(String buttonId) {
-
-    }
-}

lib/android/app/src/test/java/com/reactnativenavigation/mocks/TopTabLayoutMock.java

 import android.content.*;
 import android.view.*;
 
+import com.reactnativenavigation.interfaces.ScrollEventListener;
 import com.reactnativenavigation.viewcontrollers.*;
 
 public class TopTabLayoutMock extends View implements ComponentViewController.IReactView {
     public void sendOnNavigationButtonPressed(String buttonId) {
 
     }
+
+    @Override
+    public ScrollEventListener getScrollEventListener() {
+        return null;
+    }
 }

lib/android/app/src/test/java/com/reactnativenavigation/views/TopBarTest.java

 public class TopBarTest extends BaseTest {
     @Test
     public void title() throws Exception {
-        TopBar topBar = new TopBar(newActivity(), null, buttonId -> {}, null);
+        TopBar topBar = new TopBar(newActivity(), null, null, buttonId -> {});
         assertThat(topBar.getTitle()).isEmpty();
 
         topBar.setTitle("new title");