bluelinelabs · hansonchris · Dec 22, 2016
diff --git a/conductor/src/main/java/com/bluelinelabs/conductor/Controller.java b/conductor/src/main/java/com/bluelinelabs/conductor/Controller.java
@@ -86,6 +86,7 @@ public abstract class Controller {
     private final ArrayList<String> requestedPermissions = new ArrayList<>();
     private final ArrayList<RouterRequiringFunc> onRouterSetListeners = new ArrayList<>();
     private WeakReference<View> destroyedView;
+    private boolean recreateViewOnConfigChange;
 
     @NonNull
     static Controller newInstance(@NonNull Bundle bundle) {
@@ -618,6 +619,33 @@ public void setRetainViewMode(@NonNull RetainViewMode retainViewMode) {
         }
     }
 
+    /**
+     * Returns whether this controller should recreate its view when configuration changes.
+     *
+     * @see #setRecreateViewOnConfigChange(boolean)
+     */
+    public boolean isRecreateViewOnConfigChange() {
+        return recreateViewOnConfigChange;
+    }
+
+    /**
+     * Sets whether this Controller should recreate its view when configuration changes. This is
+     * typically necessary when the Activity has specified in the manifest that it will handle
+     * configuration changes such as an orientation change.
+     *
+     * For this method to have any effect, the Activity should set a value for {@code android:configChanges}
+     * in the manifest. Otherwise, the Activity will be destroyed and recreated, and there will be
+     * no need to explicitly recreate the view outside of that.
+     *
+     * If the top Controller has set this to {@code true} when a configuration change happens, that
+     * Controller's current view will be removed and a recreated view will be added to the parent.
+     * For Controllers that are lower in the stack, those Controllers' view will only be recreated
+     * if the Controller also has a {@link RetainViewMode} of {@link RetainViewMode#RETAIN_DETACH}.
+     */
+    public void setRecreateViewOnConfigChange(boolean recreateViewOnConfigChange) {
+        this.recreateViewOnConfigChange = recreateViewOnConfigChange;
+    }
+
     /**
      * Returns the {@link ControllerChangeHandler} that should be used for pushing this Controller, or null
      * if the handler from the {@link RouterTransaction} should be used instead.
@@ -902,6 +930,21 @@ final View inflate(@NonNull ViewGroup parent) {
             removeViewReference();
         }
 
+        return inflateAfterCheckingView(parent);
+    }
+
+    final View reinflate(@NonNull ViewGroup parent) {
+        if (view != null) {
+            detach(view, true, false);
+            removeViewReference();
+        }
+
+        view = null;
+
+        return inflateAfterCheckingView(parent);
+    }
+
+    private View inflateAfterCheckingView(@NonNull ViewGroup parent) {
         if (view == null) {
             List<LifecycleListener> listeners = new ArrayList<>(lifecycleListeners);
             for (LifecycleListener lifecycleListener : listeners) {

diff --git a/conductor/src/main/java/com/bluelinelabs/conductor/Router.java b/conductor/src/main/java/com/bluelinelabs/conductor/Router.java
@@ -2,6 +2,7 @@
 
 import android.app.Activity;
 import android.content.Intent;
+import android.content.res.Configuration;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
@@ -560,6 +561,40 @@ public final boolean onOptionsItemSelected(@NonNull MenuItem item) {
         return false;
     }
 
+    /**
+     * @see Controller#setRecreateViewOnConfigChange(boolean)
+     */
+    public final void onConfigurationChanged(Configuration newConfig) {
+        if (backstack.isEmpty()) {
+            return;
+        }
+
+        RouterTransaction topTransaction = backstack.peek();
+        Controller topController = topTransaction.controller;
+        if (topController.isRecreateViewOnConfigChange()) {
+            View currentView = topController.getView();
+            if (currentView != null) {
+                container.removeView(currentView);
+            }
+
+            View newView = topController.reinflate(container);
+            container.addView(newView);
+        }
+
+        for (RouterTransaction transaction : backstack) {
+            if (transaction == topTransaction) {
+                continue;
+            }
+
+            Controller controller = transaction.controller;
+            if (controller.isRecreateViewOnConfigChange()
+                && controller.getRetainViewMode() == Controller.RetainViewMode.RETAIN_DETACH) {
+
+                controller.reinflate(container);
+            }
+        }
+    }
+
     private void popToTransaction(@NonNull RouterTransaction transaction, @Nullable ControllerChangeHandler changeHandler) {
         RouterTransaction topTransaction = backstack.peek();
         List<RouterTransaction> poppedTransactions = backstack.popTo(transaction);

diff --git a/conductor/src/main/java/com/bluelinelabs/conductor/internal/LifecycleHandler.java b/conductor/src/main/java/com/bluelinelabs/conductor/internal/LifecycleHandler.java
@@ -6,6 +6,7 @@
 import android.app.Fragment;
 import android.content.Context;
 import android.content.Intent;
+import android.content.res.Configuration;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Parcel;
@@ -261,6 +262,15 @@ public boolean onOptionsItemSelected(MenuItem item) {
         return super.onOptionsItemSelected(item);
     }
 
+    @Override
+    public void onConfigurationChanged(Configuration newConfig) {
+        super.onConfigurationChanged(newConfig);
+
+        for (Router router : routerMap.values()) {
+            router.onConfigurationChanged(newConfig);
+        }
+    }
+
     public void registerForActivityResult(@NonNull String instanceId, int requestCode) {
         activityRequestMap.put(requestCode, instanceId);
     }

diff --git a/conductor/src/test/java/com/bluelinelabs/conductor/RouterTests.java b/conductor/src/test/java/com/bluelinelabs/conductor/RouterTests.java
@@ -1,6 +1,7 @@
 package com.bluelinelabs.conductor;
 
 import android.view.ViewGroup;
+import android.view.View;
 
 import com.bluelinelabs.conductor.util.ActivityProxy;
 import com.bluelinelabs.conductor.util.ListUtils;
@@ -13,10 +14,13 @@
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.annotation.Config;
 
+import java.util.ArrayList;
 import java.util.List;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
@@ -345,7 +349,7 @@ public void testChildRouterRearrangeTransactionBackstack() {
         Controller parent = new TestController();
         router.setRoot(RouterTransaction.with(parent));
 
-        Router childRouter = parent.getChildRouter((ViewGroup)parent.getView().findViewById(TestController.CHILD_VIEW_ID_1));
+        Router childRouter = parent.getChildRouter((ViewGroup) parent.getView().findViewById(TestController.CHILD_VIEW_ID_1));
 
         RouterTransaction transaction1 = RouterTransaction.with(new TestController());
         RouterTransaction transaction2 = RouterTransaction.with(new TestController());
@@ -371,4 +375,86 @@ public void testChildRouterRearrangeTransactionBackstack() {
         assertEquals(0, childRouter.getBackstackSize());
     }
 
+    public void testRecreateViewsOnConfigChange_notRecreatesTopControllerView() {
+        RouterTransaction rootTransaction = RouterTransaction.with(new TestController());
+        RouterTransaction topTransaction = RouterTransaction.with(new TestController()).pushChangeHandler(MockChangeHandler.noRemoveViewOnPushHandler());
+
+        List<RouterTransaction> backstack = new ArrayList<>();
+        backstack.add(rootTransaction);
+        backstack.add(topTransaction);
+
+        router.setBackstack(backstack, null);
+
+        View originalTopView = topTransaction.controller.getView();
+        router.onConfigurationChanged(null);
+        View newTopView = topTransaction.controller.getView();
+
+        assertNotNull(originalTopView);
+        assertNotNull(newTopView);
+        assertEquals(originalTopView, newTopView);
+    }
+
+    @Test
+    public void testRecreateViewsOnConfigChange_recreatesTopControllerView() {
+        RouterTransaction rootTransaction = RouterTransaction.with(new TestController());
+        RouterTransaction topTransaction = RouterTransaction.with(new TestController()).pushChangeHandler(MockChangeHandler.noRemoveViewOnPushHandler());
+        topTransaction.controller.setRecreateViewOnConfigChange(true);
+
+        List<RouterTransaction> backstack = new ArrayList<>();
+        backstack.add(rootTransaction);
+        backstack.add(topTransaction);
+
+        router.setBackstack(backstack, null);
+
+        View originalTopView = topTransaction.controller.getView();
+        router.onConfigurationChanged(null);
+        View newTopView = topTransaction.controller.getView();
+
+        assertNotNull(originalTopView);
+        assertNotNull(newTopView);
+        assertNotEquals(originalTopView, newTopView);
+    }
+
+    @Test
+    public void testRecreateViewsOnConfigChange_notRecreatesLowerControllerView() {
+        RouterTransaction rootTransaction = RouterTransaction.with(new TestController());
+        RouterTransaction topTransaction = RouterTransaction.with(new TestController()).pushChangeHandler(MockChangeHandler.noRemoveViewOnPushHandler());
+
+        List<RouterTransaction> backstack = new ArrayList<>();
+        backstack.add(rootTransaction);
+        backstack.add(topTransaction);
+
+        router.setBackstack(backstack, null);
+
+        View originalRootView = rootTransaction.controller.getView();
+        router.onConfigurationChanged(null);
+        View newRootView = rootTransaction.controller.getView();
+
+        assertNotNull(originalRootView);
+        assertNotNull(newRootView);
+        assertEquals(originalRootView, newRootView);
+    }
+
+    @Test
+    public void testRecreateViewsOnConfigChange_recreatesLowerControllerView() {
+        RouterTransaction rootTransaction = RouterTransaction.with(new TestController());
+        RouterTransaction topTransaction = RouterTransaction.with(new TestController()).pushChangeHandler(MockChangeHandler.noRemoveViewOnPushHandler());
+        rootTransaction.controller.setRecreateViewOnConfigChange(true);
+        rootTransaction.controller.setRetainViewMode(Controller.RetainViewMode.RETAIN_DETACH);
+
+        List<RouterTransaction> backstack = new ArrayList<>();
+        backstack.add(rootTransaction);
+        backstack.add(topTransaction);
+
+        router.setBackstack(backstack, null);
+
+        View originalRootView = rootTransaction.controller.getView();
+        router.onConfigurationChanged(null);
+        View newRootView = rootTransaction.controller.getView();
+
+        assertNotNull(originalRootView);
+        assertNotNull(newRootView);
+        assertNotEquals(originalRootView, newRootView);
+    }
+
 }