basic navigationController

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

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+package com.reactnativenavigation.viewcontrollers;
+
+import java.util.Stack;
+
+public class NavigationController extends ViewController {
+	private Stack<ViewController> childControllers = new Stack<>();
+
+	public NavigationController(ViewController... childControllers) {
+		for (ViewController childController : childControllers) {
+			this.childControllers.push(childController);
+		}
+	}
+
+	public Stack<ViewController> getChildControllers() {
+		return childControllers;
+	}
+
+	public void push(final ViewController child) {
+		childControllers.push(child);
+	}
+
+	public void pop() {
+		childControllers.pop();
+	}
+}

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

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+package com.reactnativenavigation.viewcontrollers;
+
+import com.reactnativenavigation.BaseTest;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Java6Assertions.assertThat;
+
+public class NavigationControllerTest extends BaseTest {
+
+	@Test
+	public void isAViewController() throws Exception {
+		assertThat(new NavigationController()).isInstanceOf(ViewController.class);
+	}
+
+	@Test
+	public void holdsAStackOfViewControllers() throws Exception {
+		assertThat(new NavigationController().getChildControllers()).isEmpty();
+		ViewController c1 = new ViewController();
+		ViewController c2 = new ViewController();
+		ViewController c3 = new ViewController();
+		assertThat(new NavigationController(c1, c2, c3).getChildControllers()).containsExactly(c1, c2, c3);
+	}
+
+	@Test
+	public void push() throws Exception {
+		NavigationController uut = new NavigationController();
+		ViewController c1 = new ViewController();
+		assertThat(uut.getChildControllers()).isEmpty();
+		uut.push(c1);
+		assertThat(uut.getChildControllers()).containsExactly(c1);
+	}
+
+	@Test
+	public void pop() throws Exception {
+		NavigationController uut = new NavigationController();
+		ViewController c1 = new ViewController();
+		ViewController c2 = new ViewController();
+		uut.push(c1);
+		uut.push(c2);
+		assertThat(uut.getChildControllers()).containsExactly(c1, c2);
+		uut.pop();
+		assertThat(uut.getChildControllers()).containsExactly(c1);
+		uut.pop();
+		assertThat(uut.getChildControllers()).isEmpty();
+	}
+}