Add requireView() to Fragment

In cases where you know that the Fragment
has a View, provide a requireView()
method that returns a @NonNull View
rather than requiring Kotlin users use
fragment.view!!

Test: new FragmentTest
BUG: 120241368
Change-Id: I6ff3759ed6b6f4975d2d858e7592ad5bfc01042f

14 files changed, 105 insertions, 55 deletions

diff --git a/fragment/api/1.1.0-alpha03.txt b/fragment/api/1.1.0-alpha03.txt
index 0e4cde92755..dd5f2a0e6e2 100644
--- a/fragment/api/1.1.0-alpha03.txt
+++ b/fragment/api/1.1.0-alpha03.txt
@@ -115,6 +115,7 @@ package androidx.fragment.app {
     method public final android.content.Context requireContext();
     method public final androidx.fragment.app.FragmentManager requireFragmentManager();
     method public final Object requireHost();
+    method public final android.view.View requireView();
     method public void setAllowEnterTransitionOverlap(boolean);
     method public void setAllowReturnTransitionOverlap(boolean);
     method public void setArguments(android.os.Bundle?);
diff --git a/fragment/api/current.txt b/fragment/api/current.txt
index 0e4cde92755..dd5f2a0e6e2 100644
--- a/fragment/api/current.txt
+++ b/fragment/api/current.txt
@@ -115,6 +115,7 @@ package androidx.fragment.app {
     method public final android.content.Context requireContext();
     method public final androidx.fragment.app.FragmentManager requireFragmentManager();
     method public final Object requireHost();
+    method public final android.view.View requireView();
     method public void setAllowEnterTransitionOverlap(boolean);
     method public void setAllowReturnTransitionOverlap(boolean);
     method public void setArguments(android.os.Bundle?);
diff --git a/fragment/src/androidTest/java/androidx/fragment/app/FragmentAnimationTest.java b/fragment/src/androidTest/java/androidx/fragment/app/FragmentAnimationTest.java
index 1f664033485..0f1f4cda6c8 100644
--- a/fragment/src/androidTest/java/androidx/fragment/app/FragmentAnimationTest.java
+++ b/fragment/src/androidTest/java/androidx/fragment/app/FragmentAnimationTest.java
@@ -450,7 +450,7 @@ public class FragmentAnimationTest {
                 .commit();
         FragmentTestUtil.waitForExecution(mActivityRule);
 
-        final View fragmentView = fragment1.getView();
+        final View fragmentView = fragment1.requireView();
 
         final TranslateAnimation xAnimation = new TranslateAnimation(0, 1000, 0, 0);
         mActivityRule.runOnUiThread(new Runnable() {
@@ -569,8 +569,8 @@ public class FragmentAnimationTest {
     private void assertPostponed(AnimatorFragment fragment, int expectedAnimators)
             throws InterruptedException {
         assertTrue(fragment.mOnCreateViewCalled);
-        assertEquals(View.VISIBLE, fragment.getView().getVisibility());
-        assertEquals(0f, fragment.getView().getAlpha(), 0f);
+        assertEquals(View.VISIBLE, fragment.requireView().getVisibility());
+        assertEquals(0f, fragment.requireView().getAlpha(), 0f);
         assertEquals(expectedAnimators, fragment.numAnimators);
     }
 
diff --git a/fragment/src/androidTest/java/androidx/fragment/app/FragmentAnimatorTest.java b/fragment/src/androidTest/java/androidx/fragment/app/FragmentAnimatorTest.java
index ec1a2a7e678..4c08a34f077 100644
--- a/fragment/src/androidTest/java/androidx/fragment/app/FragmentAnimatorTest.java
+++ b/fragment/src/androidTest/java/androidx/fragment/app/FragmentAnimatorTest.java
@@ -126,7 +126,7 @@ public class FragmentAnimatorTest {
         mActivityRule.runOnUiThread(new Runnable() {
             @Override
             public void run() {
-                assertEquals(View.GONE, fragment.getView().getVisibility());
+                assertEquals(View.GONE, fragment.requireView().getVisibility());
 
             }
         });
@@ -141,7 +141,7 @@ public class FragmentAnimatorTest {
         mActivityRule.runOnUiThread(new Runnable() {
             @Override
             public void run() {
-                assertEquals(View.VISIBLE, fragment.getView().getVisibility());
+                assertEquals(View.VISIBLE, fragment.requireView().getVisibility());
             }
         });
 
@@ -150,7 +150,7 @@ public class FragmentAnimatorTest {
         mActivityRule.runOnUiThread(new Runnable() {
             @Override
             public void run() {
-                assertEquals(View.GONE, fragment.getView().getVisibility());
+                assertEquals(View.GONE, fragment.requireView().getVisibility());
             }
         });
     }
@@ -173,7 +173,7 @@ public class FragmentAnimatorTest {
         mActivityRule.runOnUiThread(new Runnable() {
             @Override
             public void run() {
-                assertEquals(View.GONE, fragment.getView().getVisibility());
+                assertEquals(View.GONE, fragment.requireView().getVisibility());
 
             }
         });
@@ -189,7 +189,7 @@ public class FragmentAnimatorTest {
         mActivityRule.runOnUiThread(new Runnable() {
             @Override
             public void run() {
-                assertEquals(View.VISIBLE, fragment.getView().getVisibility());
+                assertEquals(View.VISIBLE, fragment.requireView().getVisibility());
             }
         });
 
@@ -198,7 +198,7 @@ public class FragmentAnimatorTest {
         mActivityRule.runOnUiThread(new Runnable() {
             @Override
             public void run() {
-                assertEquals(View.GONE, fragment.getView().getVisibility());
+                assertEquals(View.GONE, fragment.requireView().getVisibility());
             }
         });
     }
@@ -547,8 +547,8 @@ public class FragmentAnimatorTest {
     private void assertPostponed(AnimatorFragment fragment, int expectedAnimators)
             throws InterruptedException {
         assertTrue(fragment.mOnCreateViewCalled);
-        assertEquals(View.VISIBLE, fragment.getView().getVisibility());
-        assertEquals(0f, fragment.getView().getAlpha(), 0f);
+        assertEquals(View.VISIBLE, fragment.requireView().getVisibility());
+        assertEquals(0f, fragment.requireView().getAlpha(), 0f);
         assertEquals(expectedAnimators, fragment.numAnimators);
     }
 
diff --git a/fragment/src/androidTest/java/androidx/fragment/app/FragmentReorderingTest.java b/fragment/src/androidTest/java/androidx/fragment/app/FragmentReorderingTest.java
index b2890d57484..6516ae6da17 100644
--- a/fragment/src/androidTest/java/androidx/fragment/app/FragmentReorderingTest.java
+++ b/fragment/src/androidTest/java/androidx/fragment/app/FragmentReorderingTest.java
@@ -676,7 +676,7 @@ public class FragmentReorderingTest {
                 .setReorderingAllowed(true)
                 .commit();
         mFM.executePendingTransactions();
-        final View editText = fragment2.getView().findViewById(R.id.editText);
+        final View editText = fragment2.requireView().findViewById(R.id.editText);
         assertTrue(editText.isFocused());
         assertFalse(firstEditText.isFocused());
     }
diff --git a/fragment/src/androidTest/java/androidx/fragment/app/FragmentTest.java b/fragment/src/androidTest/java/androidx/fragment/app/FragmentTest.java
index 7864152929b..a5076794f06 100644
--- a/fragment/src/androidTest/java/androidx/fragment/app/FragmentTest.java
+++ b/fragment/src/androidTest/java/androidx/fragment/app/FragmentTest.java
@@ -15,6 +15,8 @@
  */
 package androidx.fragment.app;
 
+import static com.google.common.truth.Truth.assertThat;
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.fail;
@@ -69,6 +71,31 @@ public class FragmentTest {
     @SmallTest
     @UiThreadTest
     @Test
+    public void testRequireView() {
+        StrictViewFragment fragment1 = new StrictViewFragment();
+        mActivity.getSupportFragmentManager()
+                .beginTransaction()
+                .add(R.id.content, fragment1)
+                .commitNow();
+        assertThat(fragment1.requireView())
+                .isNotNull();
+    }
+
+    @SmallTest
+    @UiThreadTest
+    @Test(expected = IllegalStateException.class)
+    public void testRequireViewWithoutView() {
+        StrictFragment fragment1 = new StrictFragment();
+        mActivity.getSupportFragmentManager()
+                .beginTransaction()
+                .add(fragment1, "fragment")
+                .commitNow();
+        fragment1.requireView();
+    }
+
+    @SmallTest
+    @UiThreadTest
+    @Test
     public void testOnCreateOrder() throws Throwable {
         OrderFragment fragment1 = new OrderFragment();
         OrderFragment fragment2 = new OrderFragment();
@@ -135,7 +162,7 @@ public class FragmentTest {
         if (fragment.getView() == null) {
             FragmentTestUtil.waitForExecution(mActivityRule);
         }
-        final View view = fragment.getView();
+        final View view = fragment.requireView();
         final Animation animation = view.getAnimation();
         if (animation == null || animation.hasEnded()) {
             // animation has already completed
@@ -207,6 +234,11 @@ public class FragmentTest {
         } catch (IllegalStateException expected) {
         }
         try {
+            fragment.requireView();
+            fail();
+        } catch (IllegalStateException expected) {
+        }
+        try {
             fragment.requireFragmentManager();
             fail();
         } catch (IllegalStateException expected) {
diff --git a/fragment/src/androidTest/java/androidx/fragment/app/FragmentTransitionTest.java b/fragment/src/androidTest/java/androidx/fragment/app/FragmentTransitionTest.java
index b6c8562e15e..aab49d648c6 100644
--- a/fragment/src/androidTest/java/androidx/fragment/app/FragmentTransitionTest.java
+++ b/fragment/src/androidTest/java/androidx/fragment/app/FragmentTransitionTest.java
@@ -552,7 +552,7 @@ public class FragmentTransitionTest {
         final View endGreen = findViewById(fragment2, R.id.greenSquare);
         final View endBlue = findViewById(fragment2, R.id.blueSquare);
 
-        assertEquals(View.GONE, fragment1.getView().getVisibility());
+        assertEquals(View.GONE, fragment1.requireView().getVisibility());
         assertEquals(View.VISIBLE, startGreen.getVisibility());
         assertEquals(View.VISIBLE, startBlue.getVisibility());
 
@@ -571,7 +571,7 @@ public class FragmentTransitionTest {
         verifyAndClearTransition(fragment1.reenterTransition, null, startGreen, startBlue);
         verifyNoOtherTransitions(fragment1);
 
-        assertEquals(View.VISIBLE, fragment1.getView().getVisibility());
+        assertEquals(View.VISIBLE, fragment1.requireView().getVisibility());
         assertEquals(View.VISIBLE, startGreen.getVisibility());
         assertEquals(View.VISIBLE, startBlue.getVisibility());
 
@@ -856,7 +856,7 @@ public class FragmentTransitionTest {
     }
 
     private View findViewById(Fragment fragment, int id) {
-        return fragment.getView().findViewById(id);
+        return fragment.requireView().findViewById(id);
     }
 
     private View findGreen() {
diff --git a/fragment/src/androidTest/java/androidx/fragment/app/FragmentViewTests.java b/fragment/src/androidTest/java/androidx/fragment/app/FragmentViewTests.java
index 4547a4d798e..d958e3933b7 100644
--- a/fragment/src/androidTest/java/androidx/fragment/app/FragmentViewTests.java
+++ b/fragment/src/androidTest/java/androidx/fragment/app/FragmentViewTests.java
@@ -258,7 +258,7 @@ public class FragmentViewTests {
         final Fragment replacement1 = fm.findFragmentByTag("1");
         FragmentTestUtil.assertChildren(container, replacement1);
         assertTrue(replacement1.isHidden());
-        assertEquals(View.GONE, replacement1.getView().getVisibility());
+        assertEquals(View.GONE, replacement1.requireView().getVisibility());
     }
 
     // Removing a detached fragment should do nothing to the View and popping should bring
@@ -334,21 +334,21 @@ public class FragmentViewTests {
         FragmentTestUtil.executePendingTransactions(mActivityRule);
 
         FragmentTestUtil.assertChildren(container, fragment);
-        assertEquals(View.VISIBLE, fragment.getView().getVisibility());
+        assertEquals(View.VISIBLE, fragment.requireView().getVisibility());
 
         fm.beginTransaction().hide(fragment).addToBackStack(null).commit();
         FragmentTestUtil.executePendingTransactions(mActivityRule);
 
         FragmentTestUtil.assertChildren(container, fragment);
         assertTrue(fragment.isHidden());
-        assertEquals(View.GONE, fragment.getView().getVisibility());
+        assertEquals(View.GONE, fragment.requireView().getVisibility());
 
         fm.popBackStack();
         FragmentTestUtil.executePendingTransactions(mActivityRule);
 
         FragmentTestUtil.assertChildren(container, fragment);
         assertFalse(fragment.isHidden());
-        assertEquals(View.VISIBLE, fragment.getView().getVisibility());
+        assertEquals(View.VISIBLE, fragment.requireView().getVisibility());
     }
 
     // Hiding a hidden fragment should not throw
@@ -391,21 +391,21 @@ public class FragmentViewTests {
 
         FragmentTestUtil.assertChildren(container, fragment);
         assertTrue(fragment.isHidden());
-        assertEquals(View.GONE, fragment.getView().getVisibility());
+        assertEquals(View.GONE, fragment.requireView().getVisibility());
 
         fm.beginTransaction().show(fragment).addToBackStack(null).commit();
         FragmentTestUtil.executePendingTransactions(mActivityRule);
 
         FragmentTestUtil.assertChildren(container, fragment);
         assertFalse(fragment.isHidden());
-        assertEquals(View.VISIBLE, fragment.getView().getVisibility());
+        assertEquals(View.VISIBLE, fragment.requireView().getVisibility());
 
         fm.popBackStack();
         FragmentTestUtil.executePendingTransactions(mActivityRule);
 
         FragmentTestUtil.assertChildren(container, fragment);
         assertTrue(fragment.isHidden());
-        assertEquals(View.GONE, fragment.getView().getVisibility());
+        assertEquals(View.GONE, fragment.requireView().getVisibility());
     }
 
     // Showing a shown fragment should not throw
@@ -447,7 +447,7 @@ public class FragmentViewTests {
 
         FragmentTestUtil.assertChildren(container, fragment);
         assertFalse(fragment.isDetached());
-        assertEquals(View.VISIBLE, fragment.getView().getVisibility());
+        assertEquals(View.VISIBLE, fragment.requireView().getVisibility());
 
         fm.beginTransaction().detach(fragment).addToBackStack(null).commit();
         FragmentTestUtil.executePendingTransactions(mActivityRule);
@@ -460,7 +460,7 @@ public class FragmentViewTests {
 
         FragmentTestUtil.assertChildren(container, fragment);
         assertFalse(fragment.isDetached());
-        assertEquals(View.VISIBLE, fragment.getView().getVisibility());
+        assertEquals(View.VISIBLE, fragment.requireView().getVisibility());
     }
 
     // Detaching a hidden fragment should remove the View from the hierarchy. Then popping it should
@@ -478,7 +478,7 @@ public class FragmentViewTests {
         FragmentTestUtil.assertChildren(container, fragment);
         assertFalse(fragment.isDetached());
         assertTrue(fragment.isHidden());
-        assertEquals(View.GONE, fragment.getView().getVisibility());
+        assertEquals(View.GONE, fragment.requireView().getVisibility());
 
         fm.beginTransaction().detach(fragment).addToBackStack(null).commit();
         FragmentTestUtil.executePendingTransactions(mActivityRule);
@@ -493,7 +493,7 @@ public class FragmentViewTests {
         FragmentTestUtil.assertChildren(container, fragment);
         assertTrue(fragment.isHidden());
         assertFalse(fragment.isDetached());
-        assertEquals(View.GONE, fragment.getView().getVisibility());
+        assertEquals(View.GONE, fragment.requireView().getVisibility());
     }
 
     // Detaching a detached fragment should not throw
@@ -542,7 +542,7 @@ public class FragmentViewTests {
 
         FragmentTestUtil.assertChildren(container, fragment);
         assertFalse(fragment.isDetached());
-        assertEquals(View.VISIBLE, fragment.getView().getVisibility());
+        assertEquals(View.VISIBLE, fragment.requireView().getVisibility());
 
         fm.popBackStack();
         FragmentTestUtil.executePendingTransactions(mActivityRule);
@@ -577,7 +577,7 @@ public class FragmentViewTests {
         FragmentTestUtil.assertChildren(container, fragment);
         assertTrue(fragment.isHidden());
         assertFalse(fragment.isDetached());
-        assertEquals(View.GONE, fragment.getView().getVisibility());
+        assertEquals(View.GONE, fragment.requireView().getVisibility());
 
         fm.popBackStack();
         FragmentTestUtil.executePendingTransactions(mActivityRule);
@@ -633,7 +633,7 @@ public class FragmentViewTests {
         FragmentTestUtil.executePendingTransactions(mActivityRule);
 
         FragmentTestUtil.assertChildren(container, fragment2);
-        assertEquals(View.VISIBLE, fragment2.getView().getVisibility());
+        assertEquals(View.VISIBLE, fragment2.requireView().getVisibility());
 
         fm.popBackStack();
         FragmentTestUtil.executePendingTransactions(mActivityRule);
@@ -644,7 +644,7 @@ public class FragmentViewTests {
         assertFalse(replacement1.isHidden());
         assertTrue(replacement1.isAdded());
         assertFalse(replacement1.isDetached());
-        assertEquals(View.VISIBLE, replacement1.getView().getVisibility());
+        assertEquals(View.VISIBLE, replacement1.requireView().getVisibility());
     }
 
     // Replace of multiple fragments in a container. Popping should replace it back again
@@ -673,7 +673,7 @@ public class FragmentViewTests {
         FragmentTestUtil.executePendingTransactions(mActivityRule);
 
         FragmentTestUtil.assertChildren(container, fragment3);
-        assertEquals(View.VISIBLE, fragment3.getView().getVisibility());
+        assertEquals(View.VISIBLE, fragment3.requireView().getVisibility());
 
         fm.popBackStack();
         FragmentTestUtil.executePendingTransactions(mActivityRule);
@@ -686,13 +686,13 @@ public class FragmentViewTests {
         assertFalse(replacement1.isHidden());
         assertTrue(replacement1.isAdded());
         assertFalse(replacement1.isDetached());
-        assertEquals(View.VISIBLE, replacement1.getView().getVisibility());
+        assertEquals(View.VISIBLE, replacement1.requireView().getVisibility());
 
         // fragment2 was hidden, so it should be returned hidden
         assertTrue(replacement2.isHidden());
         assertTrue(replacement2.isAdded());
         assertFalse(replacement2.isDetached());
-        assertEquals(View.GONE, replacement2.getView().getVisibility());
+        assertEquals(View.GONE, replacement2.requireView().getVisibility());
     }
 
     // Replace of empty container. Should act as add and popping should just remove the fragment
@@ -711,7 +711,7 @@ public class FragmentViewTests {
         FragmentTestUtil.executePendingTransactions(mActivityRule);
 
         FragmentTestUtil.assertChildren(container, fragment);
-        assertEquals(View.VISIBLE, fragment.getView().getVisibility());
+        assertEquals(View.VISIBLE, fragment.requireView().getVisibility());
 
         fm.popBackStack();
         FragmentTestUtil.executePendingTransactions(mActivityRule);
@@ -845,7 +845,7 @@ public class FragmentViewTests {
         FragmentTestUtil.executePendingTransactions(mActivityRule);
         FragmentTestUtil.assertChildren(container, fragment1);
 
-        assertEquals(View.INVISIBLE, fragment1.getView().getVisibility());
+        assertEquals(View.INVISIBLE, fragment1.requireView().getVisibility());
 
         final InvisibleFragment fragment2 = new InvisibleFragment();
         fragment2.visibility = View.GONE;
@@ -856,7 +856,7 @@ public class FragmentViewTests {
         FragmentTestUtil.executePendingTransactions(mActivityRule);
         FragmentTestUtil.assertChildren(container, fragment2);
 
-        assertEquals(View.GONE, fragment2.getView().getVisibility());
+        assertEquals(View.GONE, fragment2.requireView().getVisibility());
     }
 
     // Test to ensure that popping and adding a fragment properly track the fragments added
@@ -951,8 +951,7 @@ public class FragmentViewTests {
         FragmentTestUtil.executePendingTransactions(mActivityRule);
 
         FragmentTestUtil.assertChildren(container, fragment1);
-        ViewGroup innerContainer = (ViewGroup)
-                fragment1.getView().findViewById(R.id.fragmentContainer1);
+        ViewGroup innerContainer = fragment1.requireView().findViewById(R.id.fragmentContainer1);
 
         Fragment fragment2 = fragment1.getChildFragmentManager().findFragmentByTag("inner");
         FragmentTestUtil.assertChildren(innerContainer, fragment2);
diff --git a/fragment/src/androidTest/java/androidx/fragment/app/PostponedTransitionTest.java b/fragment/src/androidTest/java/androidx/fragment/app/PostponedTransitionTest.java
index 86e68e62fdf..1a52b437533 100644
--- a/fragment/src/androidTest/java/androidx/fragment/app/PostponedTransitionTest.java
+++ b/fragment/src/androidTest/java/androidx/fragment/app/PostponedTransitionTest.java
@@ -367,8 +367,8 @@ public class PostponedTransitionTest {
         clearTargets(fragment1);
         clearTargets(fragment2);
 
-        final View startBlue1 = fragment1.getView().findViewById(R.id.blueSquare);
-        final View startBlue2 = fragment2.getView().findViewById(R.id.blueSquare);
+        final View startBlue1 = fragment1.requireView().findViewById(R.id.blueSquare);
+        final View startBlue2 = fragment2.requireView().findViewById(R.id.blueSquare);
 
         final TransitionFragment fragment3 = new PostponedFragment2();
 
@@ -465,8 +465,8 @@ public class PostponedTransitionTest {
         clearTargets(fragment1);
         clearTargets(fragment2);
 
-        final View startBlue1 = fragment1.getView().findViewById(R.id.blueSquare);
-        final View startBlue2 = fragment2.getView().findViewById(R.id.blueSquare);
+        final View startBlue1 = fragment1.requireView().findViewById(R.id.blueSquare);
+        final View startBlue2 = fragment2.requireView().findViewById(R.id.blueSquare);
 
         final TransitionFragment fragment3 = new PostponedFragment2();
 
@@ -563,8 +563,8 @@ public class PostponedTransitionTest {
         clearTargets(fragment1);
         clearTargets(fragment2);
 
-        final View startBlue1 = fragment1.getView().findViewById(R.id.blueSquare);
-        final View startBlue2 = fragment2.getView().findViewById(R.id.blueSquare);
+        final View startBlue1 = fragment1.requireView().findViewById(R.id.blueSquare);
+        final View startBlue2 = fragment2.requireView().findViewById(R.id.blueSquare);
 
         final TransitionFragment fragment3 = new PostponedFragment2();
         final StrictFragment strictFragment1 = new StrictFragment();
@@ -621,7 +621,7 @@ public class PostponedTransitionTest {
     @Test
     public void commitNowStartsPostponed() throws Throwable {
         final FragmentManager fm = mActivityRule.getActivity().getSupportFragmentManager();
-        final View startBlue1 = mBeginningFragment.getView().findViewById(R.id.blueSquare);
+        final View startBlue1 = mBeginningFragment.requireView().findViewById(R.id.blueSquare);
 
         final TransitionFragment fragment2 = new PostponedFragment2();
         final TransitionFragment fragment1 = new PostponedFragment1();
@@ -634,7 +634,7 @@ public class PostponedTransitionTest {
                 .commit();
         FragmentTestUtil.waitForExecution(mActivityRule);
 
-        final View startBlue2 = fragment2.getView().findViewById(R.id.blueSquare);
+        final View startBlue2 = fragment2.requireView().findViewById(R.id.blueSquare);
 
         mInstrumentation.runOnMainSync(new Runnable() {
             @Override
@@ -709,7 +709,7 @@ public class PostponedTransitionTest {
     @Test
     public void popPostponedTransaction() throws Throwable {
         final FragmentManager fm = mActivityRule.getActivity().getSupportFragmentManager();
-        final View startBlue = mBeginningFragment.getView().findViewById(R.id.blueSquare);
+        final View startBlue = mBeginningFragment.requireView().findViewById(R.id.blueSquare);
 
         final TransitionFragment fragment = new PostponedFragment2();
 
@@ -892,7 +892,7 @@ public class PostponedTransitionTest {
         assertEquals(0, start.sharedElementReturn.targets.size());
         assertEquals(0, end.sharedElementReturn.targets.size());
 
-        final View blue = end.getView().findViewById(R.id.blueSquare);
+        final View blue = end.requireView().findViewById(R.id.blueSquare);
         assertTrue(end.sharedElementEnter.targets.contains(blue));
         assertEquals("blueSquare", end.sharedElementEnter.targets.get(0).getTransitionName());
         assertEquals("blueSquare", end.sharedElementEnter.targets.get(1).getTransitionName());
@@ -926,7 +926,7 @@ public class PostponedTransitionTest {
         assertEquals(2, start.sharedElementReturn.targets.size());
         assertEquals(0, end.sharedElementReturn.targets.size());
 
-        final View blue = end.getView().findViewById(R.id.blueSquare);
+        final View blue = end.requireView().findViewById(R.id.blueSquare);
         assertTrue(start.sharedElementReturn.targets.contains(blue));
         assertEquals("blueSquare", start.sharedElementReturn.targets.get(0).getTransitionName());
         assertEquals("blueSquare", start.sharedElementReturn.targets.get(1).getTransitionName());
diff --git a/fragment/src/main/java/androidx/fragment/app/Fragment.java b/fragment/src/main/java/androidx/fragment/app/Fragment.java
index 7e3c0f843dc..a9f08dfd3c9 100644
--- a/fragment/src/main/java/androidx/fragment/app/Fragment.java
+++ b/fragment/src/main/java/androidx/fragment/app/Fragment.java
@@ -1597,6 +1597,22 @@ public class Fragment implements ComponentCallbacks, OnCreateContextMenuListener
     }
 
     /**
+     * Get the root view for the fragment's layout (the one returned by {@link #onCreateView}).
+     *
+     * @throws IllegalStateException if no view was returned by {@link #onCreateView}.
+     * @see #getView()
+     */
+    @NonNull
+    public final View requireView() {
+        View view = getView();
+        if (view == null) {
+            throw new IllegalStateException("Fragment " + this + " did not return a View from"
+                    + " onCreateView() or this was called before onCreateView().");
+        }
+        return view;
+    }
+
+    /**
      * Called when the fragment's activity has been created and this
      * fragment's view hierarchy instantiated.  It can be used to do final
      * initialization once these pieces are in place, such as retrieving
diff --git a/fragment/src/main/java/androidx/fragment/app/FragmentManagerImpl.java b/fragment/src/main/java/androidx/fragment/app/FragmentManagerImpl.java
index b70f69776c6..acee49928ea 100644
--- a/fragment/src/main/java/androidx/fragment/app/FragmentManagerImpl.java
+++ b/fragment/src/main/java/androidx/fragment/app/FragmentManagerImpl.java
@@ -1890,7 +1890,7 @@ final class FragmentManagerImpl extends FragmentManager implements LayoutInflate
         for (int i = 0; i < numAdded; i++) {
             final Fragment fragment = fragments.valueAt(i);
             if (!fragment.mAdded) {
-                final View view = fragment.getView();
+                final View view = fragment.requireView();
                 fragment.mPostponedAlpha = view.getAlpha();
                 view.setAlpha(0f);
             }
diff --git a/fragment/src/main/java/androidx/fragment/app/FragmentTransition.java b/fragment/src/main/java/androidx/fragment/app/FragmentTransition.java
index b8273a0471f..642058df2b6 100644
--- a/fragment/src/main/java/androidx/fragment/app/FragmentTransition.java
+++ b/fragment/src/main/java/androidx/fragment/app/FragmentTransition.java
@@ -561,7 +561,7 @@ class FragmentTransition {
         final Fragment inFragment = fragments.lastIn;
         final Fragment outFragment = fragments.firstOut;
         if (inFragment != null) {
-            inFragment.getView().setVisibility(View.VISIBLE);
+            inFragment.requireView().setVisibility(View.VISIBLE);
         }
         if (inFragment == null || outFragment == null) {
             return null; // no shared element without a fragment
@@ -786,7 +786,7 @@ class FragmentTransition {
         }
         final Fragment outFragment = fragments.firstOut;
         final ArrayMap<String, View> outSharedElements = new ArrayMap<>();
-        impl.findNamedViews(outSharedElements, outFragment.getView());
+        impl.findNamedViews(outSharedElements, outFragment.requireView());
 
         final SharedElementCallback sharedElementCallback;
         final ArrayList<String> names;
diff --git a/fragment/src/main/java/androidx/fragment/app/FragmentTransitionImpl.java b/fragment/src/main/java/androidx/fragment/app/FragmentTransitionImpl.java
index 33ba74ef363..7aeeab7066e 100644
--- a/fragment/src/main/java/androidx/fragment/app/FragmentTransitionImpl.java
+++ b/fragment/src/main/java/androidx/fragment/app/FragmentTransitionImpl.java
@@ -23,6 +23,7 @@ import android.graphics.Rect;
 import android.view.View;
 import android.view.ViewGroup;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.RestrictTo;
 import androidx.core.view.OneShotPreDrawListener;
 import androidx.core.view.ViewCompat;
@@ -211,7 +212,7 @@ public abstract class FragmentTransitionImpl {
      * Finds all views that have transition names in the hierarchy under the given view and
      * stores them in {@code namedViews} map with the name as the key.
      */
-    void findNamedViews(Map<String, View> namedViews, View view) {
+    void findNamedViews(Map<String, View> namedViews, @NonNull View view) {
         if (view.getVisibility() == View.VISIBLE) {
             String transitionName = ViewCompat.getTransitionName(view);
             if (transitionName != null) {
diff --git a/fragment/src/main/java/androidx/fragment/app/ListFragment.java b/fragment/src/main/java/androidx/fragment/app/ListFragment.java
index e1e087bd44b..adbcb677603 100644
--- a/fragment/src/main/java/androidx/fragment/app/ListFragment.java
+++ b/fragment/src/main/java/androidx/fragment/app/ListFragment.java
@@ -189,7 +189,7 @@ public class ListFragment extends Fragment {
             if (!mListShown && !hadAdapter) {
                 // The list was hidden, and previously didn't have an
                 // adapter.  It is now time to show it.
-                setListShown(true, getView().getWindowToken() != null);
+                setListShown(true, requireView().getWindowToken() != null);
             }
         }
     }