push animation

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

+package com.reactnativenavigation.anim;
+
+import android.animation.Animator;
+import android.animation.AnimatorListenerAdapter;
+import android.animation.AnimatorSet;
+import android.animation.ObjectAnimator;
+import android.view.View;
+import android.view.animation.DecelerateInterpolator;
+
+public class StackAnimator {
+	public void animatePush(final View target, final Runnable onComplete) {
+		target.setAlpha(0);
+		target.setTranslationY(0.08f * ((View) target.getParent()).getHeight());
+
+		ObjectAnimator alpha = ObjectAnimator.ofFloat(target, View.ALPHA, 1);
+		alpha.setInterpolator(new DecelerateInterpolator());
+		alpha.setDuration(200);
+
+		ObjectAnimator translationY = ObjectAnimator.ofFloat(target, View.TRANSLATION_Y, 0);
+		translationY.setInterpolator(new DecelerateInterpolator());
+		translationY.setDuration(350);
+
+		AnimatorSet set = new AnimatorSet();
+		set.playTogether(translationY, alpha);
+		set.addListener(new AnimatorListenerAdapter() {
+			@Override
+			public void onAnimationEnd(final Animator animation) {
+				if (onComplete != null) onComplete.run();
+			}
+		});
+		set.start();
+	}
+}

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

 import android.view.ViewGroup;
 import android.widget.FrameLayout;
 
+import com.reactnativenavigation.anim.StackAnimator;
+
 import java.util.Collection;
 
 public class StackController extends ParentController {
 	private final IndexedStack<ViewController> stack = new IndexedStack<>();
+	private StackAnimator animator;
 
 	public StackController(final Activity activity, String id) {
+		this(activity, id, new StackAnimator());
+	}
+
+	public StackController(final Activity activity, String id, StackAnimator animator) {
 		super(activity, id);
+		this.animator = animator;
 	}
 
 	public void push(final ViewController child) {
 		stack.push(child.getId(), child);
 
 		getView().addView(child.getView());
+
 		if (previousTop != null) {
-			getView().removeView(previousTop.getView());
+			animator.animatePush(child.getView(), new Runnable() {
+				@Override
+				public void run() {
+					getView().removeView(previousTop.getView());
+				}
+			});
 		}
 	}
 

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

+package com.reactnativenavigation.mocks;
+
+import android.view.View;
+
+import com.reactnativenavigation.anim.StackAnimator;
+
+public class TestStackAnimator extends StackAnimator {
+	@Override
+	public void animatePush(final View target, final Runnable onComplete) {
+		if (onComplete != null) onComplete.run();
+	}
+}

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

 
 import com.reactnativenavigation.BaseTest;
 import com.reactnativenavigation.mocks.SimpleViewController;
+import com.reactnativenavigation.mocks.TestStackAnimator;
 
 import org.junit.Test;
 import org.robolectric.Shadows;
 
 	@Test
 	public void push() throws Exception {
-		StackController stackController = new StackController(activity, "stack1");
+		StackController stackController = new StackController(activity, "stack1", new TestStackAnimator());
 		stackController.push(child1);
 		uut.setRoot(stackController);
 
 	@Test
 	public void push_OnCorrectStackByFindingChildId() throws Exception {
 		BottomTabsController bottomTabsController = new BottomTabsController(activity, "tabsController");
-		StackController stack1 = new StackController(activity, "stack1");
-		StackController stack2 = new StackController(activity, "stack2");
+		StackController stack1 = new StackController(activity, "stack1", new TestStackAnimator());
+		StackController stack2 = new StackController(activity, "stack2", new TestStackAnimator());
 		stack1.push(child1);
 		stack2.push(child2);
 		bottomTabsController.setTabs(Arrays.<ViewController>asList(stack1, stack2));
 	@Test
 	public void pop_FromCorrectStackByFindingChildId() throws Exception {
 		BottomTabsController bottomTabsController = new BottomTabsController(activity, "tabsController");
-		StackController stack1 = new StackController(activity, "stack1");
-		StackController stack2 = new StackController(activity, "stack2");
+		StackController stack1 = new StackController(activity, "stack1", new TestStackAnimator());
+		StackController stack2 = new StackController(activity, "stack2", new TestStackAnimator());
 		stack1.push(child1);
 		stack2.push(child2);
 		stack2.push(child3);
 	@Test
 	public void popSpecific() throws Exception {
 		BottomTabsController bottomTabsController = new BottomTabsController(activity, "tabsController");
-		StackController stack1 = new StackController(activity, "stack1");
-		StackController stack2 = new StackController(activity, "stack2");
+		StackController stack1 = new StackController(activity, "stack1", new TestStackAnimator());
+		StackController stack2 = new StackController(activity, "stack2", new TestStackAnimator());
 		stack1.push(child1);
 		stack2.push(child2);
 		stack2.push(child3);
 	@Test
 	public void popTo_FromCorrectStackUpToChild() throws Exception {
 		BottomTabsController bottomTabsController = new BottomTabsController(activity, "tabsController");
-		StackController stack1 = new StackController(activity, "stack1");
-		StackController stack2 = new StackController(activity, "stack2");
+		StackController stack1 = new StackController(activity, "stack1", new TestStackAnimator());
+		StackController stack2 = new StackController(activity, "stack2", new TestStackAnimator());
 		stack1.push(child1);
 		stack2.push(child2);
 		stack2.push(child3);
 	@Test
 	public void popToRoot() throws Exception {
 		BottomTabsController bottomTabsController = new BottomTabsController(activity, "tabsController");
-		StackController stack1 = new StackController(activity, "stack1");
-		StackController stack2 = new StackController(activity, "stack2");
+		StackController stack1 = new StackController(activity, "stack1", new TestStackAnimator());
+		StackController stack2 = new StackController(activity, "stack2", new TestStackAnimator());
 		stack1.push(child1);
 		stack2.push(child2);
 		stack2.push(child3);

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

 
 import com.reactnativenavigation.BaseTest;
 import com.reactnativenavigation.mocks.SimpleViewController;
+import com.reactnativenavigation.mocks.TestStackAnimator;
 
 import org.junit.Test;
 
 	public void beforeEach() {
 		super.beforeEach();
 		activity = newActivity();
-		uut = new StackController(activity, "uut");
+		uut = new StackController(activity, "uut", new TestStackAnimator());
 		child1 = new SimpleViewController(activity, "child1");
 		child2 = new SimpleViewController(activity, "child2");
 		child3 = new SimpleViewController(activity, "child3");
 		uut.push(child1);
 		assertThat(child1.getParentStackController()).isEqualTo(uut);
 
-		StackController anotherNavController = new StackController(activity, "another");
+		StackController anotherNavController = new StackController(activity, "another", new TestStackAnimator());
 		anotherNavController.push(child2);
 		assertThat(child2.getParentStackController()).isEqualTo(anotherNavController);
 	}
 
 	@Test
 	public void findControllerById_Deeply() throws Exception {
-		StackController stack = new StackController(activity, "stack2");
+		StackController stack = new StackController(activity, "stack2", new TestStackAnimator());
 		stack.push(child2);
 		uut.push(stack);
 		assertThat(uut.findControllerById(child2.getId())).isEqualTo(child2);