Add a better fragment support in BaseSetupWizardActivity

 - by adding the frame layout for fragment rendering in
split-nav layouts
 - by adding necessary unit tests.

Test: added necessary unit tests.

BUG: 204211185

Change-Id: I27f234d6db1c280df56bcb06a180318b60c77454

2 files changed, 77 insertions, 8 deletions

diff --git a/library/main/src/com/android/car/setupwizardlib/BaseSetupWizardActivity.java b/library/main/src/com/android/car/setupwizardlib/BaseSetupWizardActivity.java
index 1addd71..f8d9342 100644
--- a/library/main/src/com/android/car/setupwizardlib/BaseSetupWizardActivity.java
+++ b/library/main/src/com/android/car/setupwizardlib/BaseSetupWizardActivity.java
@@ -176,6 +176,7 @@ abstract class BaseSetupWizardActivity extends FragmentActivity {
     @CallSuper
     protected void setContentFragmentWithBackstack(Fragment fragment) {
         if (mAllowFragmentCommits) {
+            inflateEmptyFragmentFrameLayout();
             getSupportFragmentManager().beginTransaction()
                     .replace(getFragmentContainerViewId(), fragment, CONTENT_FRAGMENT_TAG)
                     .addToBackStack(null)
@@ -199,6 +200,7 @@ abstract class BaseSetupWizardActivity extends FragmentActivity {
     @CallSuper
     protected void setContentFragment(Fragment fragment) {
         if (mAllowFragmentCommits) {
+            inflateEmptyFragmentFrameLayout();
             getSupportFragmentManager().beginTransaction()
                     .setCustomAnimations(
                             android.R.animator.fade_in,
@@ -539,17 +541,26 @@ abstract class BaseSetupWizardActivity extends FragmentActivity {
 
     @VisibleForTesting
     int getFragmentContainerViewId() {
-        if (isSplitNavLayoutSupported()) {
-            ViewStub viewStub = findViewById(R.id.layout_content_stub);
+        // Check if the inflated frame layout is still available. Add the fragment to frame
+        // layout only if it's available. Otherwise, fall back to default layout to attach
+        // fragment. Note that frame layout might not be available if hosting activity inflated
+        // viewStub already with other views than before calling setFragmentContent().
+        View frameLayout = findViewById(R.id.empty_fragment_frame_layout);
+        int containerViewId = frameLayout == null ? R.id.car_setup_wizard_layout :
+                R.id.empty_fragment_frame_layout;
+        Log.v(TAG, "fragmentContainerViewId: "
+                + getResources().getResourceEntryName(containerViewId));
+        return containerViewId;
+
+    }
+
+    @VisibleForTesting
+    void inflateEmptyFragmentFrameLayout() {
+        ViewStub viewStub = findViewById(R.id.layout_content_stub);
+        if (viewStub != null) {
             viewStub.setLayoutResource(R.layout.empty_fragment_frame_layout);
             viewStub.inflate();
-            Log.v(TAG, "fragmentContainerViewId: "
-                    + getResources().getResourceEntryName(R.id.empty_fragment_frame_layout));
-            return R.id.empty_fragment_frame_layout;
         }
-        Log.v(TAG, "fragmentContainerViewId: "
-                + getResources().getResourceEntryName(R.id.car_setup_wizard_layout));
-        return R.id.car_setup_wizard_layout;
     }
 
     @VisibleForTesting
diff --git a/library/main/tests/robotests/src/com/android/car/setupwizardlib/BaseCompatActivityTest.java b/library/main/tests/robotests/src/com/android/car/setupwizardlib/BaseCompatActivityTest.java
index 5cb9ef0..b504625 100644
--- a/library/main/tests/robotests/src/com/android/car/setupwizardlib/BaseCompatActivityTest.java
+++ b/library/main/tests/robotests/src/com/android/car/setupwizardlib/BaseCompatActivityTest.java
@@ -34,6 +34,7 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewStub;
 import android.widget.Button;
+import android.widget.FrameLayout;
 import android.widget.ImageView;
 
 import androidx.annotation.StyleRes;
@@ -626,4 +627,61 @@ public class BaseCompatActivityTest extends BaseRobolectricTest {
         spyBaseCompatActivity.nextAction(Activity.RESULT_OK);
         verify(spyBaseCompatActivity, times(2)).startActivity(Mockito.any());
     }
+
+    /**
+     * Test that {@link BaseCompatActivity#getFragmentContainerViewId()} returns
+     * layout_content_fragment when split-nav is enabled and view stub is not inflated yet.
+     */
+    @Test
+    public void testGetFragmentContainerViewId_viewStubNotInflated() {
+        BaseCompatActivity spyBaseCompatActivity = createSpyBaseCompatActivity();
+        FrameLayout mockFrameLayout = mock(FrameLayout.class);
+        ViewStub mockViewStub = mock(ViewStub.class);
+        when(spyBaseCompatActivity.findViewById(R.id.empty_fragment_frame_layout))
+                .thenReturn(mockFrameLayout);
+        when(spyBaseCompatActivity.findViewById(R.id.layout_content_stub)).thenReturn(mockViewStub);
+
+        int fragmentContainerViewId = spyBaseCompatActivity.getFragmentContainerViewId();
+
+        verify(mockViewStub, times(1)).inflate();
+        assertThat(fragmentContainerViewId).isEqualTo(R.id.empty_fragment_frame_layout);
+    }
+
+    /**
+     * Test that {@link BaseCompatActivity#getFragmentContainerViewId()} returns
+     * layout_content_fragment when split-nav is enabled and view stub is already inflated
+     * with frame layout for fragment attachment.
+     */
+    @Test
+    public void testGetFragmentContainerViewId_viewStubInflatedFrameLayout() {
+        BaseCompatActivity spyBaseCompatActivity = createSpyBaseCompatActivity();
+        FrameLayout mockFrameLayout = mock(FrameLayout.class);
+        when(spyBaseCompatActivity.findViewById(R.id.empty_fragment_frame_layout))
+                .thenReturn(mockFrameLayout);
+        when(spyBaseCompatActivity.findViewById(R.id.layout_content_stub))
+                .thenReturn(null);
+
+        int fragmentContainerViewId = spyBaseCompatActivity.getFragmentContainerViewId();
+
+        assertThat(fragmentContainerViewId).isEqualTo(R.id.empty_fragment_frame_layout);
+    }
+
+    /**
+     * Test that {@link BaseCompatActivity#getFragmentContainerViewId()} returns
+     * layout_content_fragment when split-nav is enabled and view stub is already inflated
+     * with some other view than fragment layout. The frame layout is not available for fragment
+     * attachment.
+     */
+    @Test
+    public void testGetFragmentContainerViewId_frameLayoutNotAvailable() {
+        BaseCompatActivity spyBaseCompatActivity = createSpyBaseCompatActivity();
+        when(spyBaseCompatActivity.findViewById(R.id.layout_content_stub))
+                .thenReturn(null);
+        when(spyBaseCompatActivity.findViewById(R.id.empty_fragment_frame_layout))
+                .thenReturn(null);
+
+        int fragmentContainerViewId = spyBaseCompatActivity.getFragmentContainerViewId();
+
+        assertThat(fragmentContainerViewId).isEqualTo(R.id.car_setup_wizard_layout);
+    }
 }