Merge "Show topology pane in per-display fragment" into main

src/com/android/settings/connecteddevice/display/DisplayTopology.kt

@@ -159,8 +159,6 @@ class TopologyScale(
     }
 }
 
-const val TOPOLOGY_PREFERENCE_KEY = "display_topology_preference"
-
 /** Represents a draggable block in the topology pane. */
 class DisplayBlock(context : Context) : Button(context) {
     @VisibleForTesting var mSelectedImage: Drawable = ColorDrawable(Color.BLACK)
@@ -240,7 +238,6 @@ class DisplayTopologyPreference(context : Context)
         // Prevent highlight when hovering with mouse.
         isSelectable = false
 
-        key = TOPOLOGY_PREFERENCE_KEY
         isPersistent = false
 
         injector = Injector(context)

src/com/android/settings/connecteddevice/display/ExternalDisplayPreferenceFragment.java

@@ -64,33 +64,69 @@ import java.util.List;
  * The Settings screen for External Displays configuration and connection management.
  */
 public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmentBase {
+    @VisibleForTesting enum PrefBasics {
+        DISPLAY_TOPOLOGY(10, "display_topology_preference", null),
+        MIRROR(20, "mirror_preference", null),
+
+        // If shown, use toggle should be before other per-display settings.
+        EXTERNAL_DISPLAY_USE(30, "external_display_use_preference",
+                R.string.external_display_use_title),
+
+        ILLUSTRATION(35, "external_display_illustration", null),
+
+        // If shown, external display size is before other per-display settings.
+        EXTERNAL_DISPLAY_SIZE(40, "external_display_size", R.string.screen_zoom_title),
+        EXTERNAL_DISPLAY_ROTATION(50, "external_display_rotation",
+                R.string.external_display_rotation),
+        EXTERNAL_DISPLAY_RESOLUTION(60, "external_display_resolution",
+                R.string.external_display_resolution_settings_title),
+
+        // Built-in display link is after per-display settings.
+        BUILTIN_DISPLAY_LIST(70, "builtin_display_list_preference",
+                R.string.builtin_display_settings_category),
+
+        DISPLAYS_LIST(80, "displays_list_preference", null),
+
+        // If shown, footer should appear below everything.
+        FOOTER(90, "footer_preference", null);
+
+
+        PrefBasics(int order, String key, @Nullable Integer titleResource) {
+            this.order = order;
+            this.key = key;
+            this.titleResource = titleResource;
+        }
+
+        // Fields must be public to make the linter happy.
+        public final int order;
+        public final String key;
+        @Nullable public final Integer titleResource;
+
+        void apply(Preference preference) {
+            if (order != -1) {
+                preference.setOrder(order);
+            }
+            if (titleResource != null) {
+                preference.setTitle(titleResource);
+            }
+            preference.setKey(key);
+            preference.setPersistent(false);
+        }
+    }
+
     static final int EXTERNAL_DISPLAY_SETTINGS_RESOURCE = R.xml.external_display_settings;
-    static final String DISPLAYS_LIST_PREFERENCE_KEY = "displays_list_preference";
-    static final String BUILTIN_DISPLAY_LIST_PREFERENCE_KEY = "builtin_display_list_preference";
-    static final String EXTERNAL_DISPLAY_USE_PREFERENCE_KEY = "external_display_use_preference";
-    static final String EXTERNAL_DISPLAY_ROTATION_KEY = "external_display_rotation";
-    static final String EXTERNAL_DISPLAY_RESOLUTION_PREFERENCE_KEY = "external_display_resolution";
-    static final String EXTERNAL_DISPLAY_SIZE_PREFERENCE_KEY = "external_display_size";
     static final int EXTERNAL_DISPLAY_CHANGE_RESOLUTION_FOOTER_RESOURCE =
             R.string.external_display_change_resolution_footer_title;
     static final int EXTERNAL_DISPLAY_LANDSCAPE_DRAWABLE =
             R.drawable.external_display_mirror_landscape;
     static final int EXTERNAL_DISPLAY_TITLE_RESOURCE =
             R.string.external_display_settings_title;
-    static final int EXTERNAL_DISPLAY_USE_TITLE_RESOURCE =
-            R.string.external_display_use_title;
     static final int EXTERNAL_DISPLAY_NOT_FOUND_FOOTER_RESOURCE =
             R.string.external_display_not_found_footer_title;
     static final int EXTERNAL_DISPLAY_PORTRAIT_DRAWABLE =
             R.drawable.external_display_mirror_portrait;
-    static final int EXTERNAL_DISPLAY_ROTATION_TITLE_RESOURCE =
-            R.string.external_display_rotation;
-    static final int EXTERNAL_DISPLAY_RESOLUTION_TITLE_RESOURCE =
-            R.string.external_display_resolution_settings_title;
-    static final int EXTERNAL_DISPLAY_SIZE_TITLE_RESOURCE = R.string.screen_zoom_title;
     static final int EXTERNAL_DISPLAY_SIZE_SUMMARY_RESOURCE = R.string.screen_zoom_short_summary;
-    static final int BUILTIN_DISPLAY_SETTINGS_CATEGORY_RESOURCE =
+
-            R.string.builtin_display_settings_category;
     @VisibleForTesting
     static final String PREVIOUSLY_SHOWN_LIST_KEY = "mPreviouslyShownListOfDisplays";
     private boolean mStarted;
@@ -253,9 +289,7 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
     ListPreference getRotationPreference(@NonNull Context context) {
         if (mRotationPref == null) {
             mRotationPref = new ListPreference(context);
-            mRotationPref.setPersistent(false);
+            PrefBasics.EXTERNAL_DISPLAY_ROTATION.apply(mRotationPref);
-            mRotationPref.setKey(EXTERNAL_DISPLAY_ROTATION_KEY);
-            mRotationPref.setTitle(EXTERNAL_DISPLAY_ROTATION_TITLE_RESOURCE);
         }
         return mRotationPref;
     }
@@ -265,9 +299,7 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
     Preference getResolutionPreference(@NonNull Context context) {
         if (mResolutionPreference == null) {
             mResolutionPreference = new Preference(context);
-            mResolutionPreference.setPersistent(false);
+            PrefBasics.EXTERNAL_DISPLAY_RESOLUTION.apply(mResolutionPreference);
-            mResolutionPreference.setKey(EXTERNAL_DISPLAY_RESOLUTION_PREFERENCE_KEY);
-            mResolutionPreference.setTitle(EXTERNAL_DISPLAY_RESOLUTION_TITLE_RESOURCE);
         }
         return mResolutionPreference;
     }
@@ -277,9 +309,7 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
     MainSwitchPreference getUseDisplayPreference(@NonNull Context context) {
         if (mUseDisplayPref == null) {
             mUseDisplayPref = new MainSwitchPreference(context);
-            mUseDisplayPref.setPersistent(false);
+            PrefBasics.EXTERNAL_DISPLAY_USE.apply(mUseDisplayPref);
-            mUseDisplayPref.setKey(EXTERNAL_DISPLAY_USE_PREFERENCE_KEY);
-            mUseDisplayPref.setTitle(EXTERNAL_DISPLAY_USE_TITLE_RESOURCE);
         }
         return mUseDisplayPref;
     }
@@ -289,8 +319,7 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
     IllustrationPreference getIllustrationPreference(@NonNull Context context) {
         if (mImagePreference == null) {
             mImagePreference = new IllustrationPreference(context);
-            mImagePreference.setPersistent(false);
+            PrefBasics.ILLUSTRATION.apply(mImagePreference);
-            mImagePreference.setKey("external_display_illustration");
         }
         return mImagePreference;
     }
@@ -308,9 +337,7 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
     private PreferenceCategory getDisplaysListPreference(@NonNull Context context) {
         if (mDisplaysPreference == null) {
             mDisplaysPreference = new PreferenceCategory(context);
-            mDisplaysPreference.setPersistent(false);
+            PrefBasics.DISPLAYS_LIST.apply(mDisplaysPreference);
-            mDisplaysPreference.setOrder(40);
-            mDisplaysPreference.setKey(DISPLAYS_LIST_PREFERENCE_KEY);
         }
         return mDisplaysPreference;
     }
@@ -319,10 +346,7 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
     private PreferenceCategory getBuiltinDisplayListPreference(@NonNull Context context) {
         if (mBuiltinDisplayPreference == null) {
             mBuiltinDisplayPreference = new PreferenceCategory(context);
-            mBuiltinDisplayPreference.setPersistent(false);
+            PrefBasics.BUILTIN_DISPLAY_LIST.apply(mBuiltinDisplayPreference);
-            mBuiltinDisplayPreference.setOrder(30);
-            mBuiltinDisplayPreference.setKey(BUILTIN_DISPLAY_LIST_PREFERENCE_KEY);
-            mBuiltinDisplayPreference.setTitle(BUILTIN_DISPLAY_SETTINGS_CATEGORY_RESOURCE);
         }
         return mBuiltinDisplayPreference;
     }
@@ -338,7 +362,7 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
     @NonNull Preference getDisplayTopologyPreference(@NonNull Context context) {
         if (mDisplayTopologyPreference == null) {
             mDisplayTopologyPreference = new DisplayTopologyPreference(context);
-            mDisplayTopologyPreference.setOrder(10);
+            PrefBasics.DISPLAY_TOPOLOGY.apply(mDisplayTopologyPreference);
         }
         return mDisplayTopologyPreference;
     }
@@ -346,7 +370,7 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
     @NonNull Preference getMirrorPreference(@NonNull Context context) {
         if (mMirrorPreference == null) {
             mMirrorPreference = new MirrorPreference(context);
-            mMirrorPreference.setOrder(20);
+            PrefBasics.MIRROR.apply(mMirrorPreference);
         }
         return mMirrorPreference;
     }
@@ -386,16 +410,18 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
 
     private void updateScreenForDisplayId(final int displayId,
             @NonNull final PrefRefresh screen, @NonNull Context context) {
-        final boolean forceShowList = displayId == INVALID_DISPLAY
-                && isTopologyPaneEnabled(mInjector);
         final var displaysToShow = externalDisplaysToShow(displayId);
 
-        if (!forceShowList && displaysToShow.isEmpty() && displayId == INVALID_DISPLAY) {
+        if (displaysToShow.isEmpty() && displayId == INVALID_DISPLAY) {
             showTextWhenNoDisplaysToShow(screen, context);
-        } else if (!forceShowList && displaysToShow.size() == 1
+        } else if (displaysToShow.size() == 1
                 && ((displayId == INVALID_DISPLAY && !mPreviouslyShownListOfDisplays)
                         || displaysToShow.get(0).getDisplayId() == displayId)) {
             showDisplaySettings(displaysToShow.get(0), screen, context);
+            if (displayId == INVALID_DISPLAY && isTopologyPaneEnabled(mInjector)) {
+                // Only show the topology pane if the user did not arrive via the displays list.
+                maybeAddV2Components(context, screen);
+            }
         } else if (displayId == INVALID_DISPLAY) {
             // If ever shown a list of displays - keep showing it for consistency after
             // disconnecting one of the displays, and only one display is left.
@@ -446,21 +472,30 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
         screen.addPreference(updateResolutionPreference(context, display));
         screen.addPreference(updateRotationPreference(context, display, displayRotation));
         if (isResolutionSettingEnabled(mInjector)) {
+            // Do not show the footer about changing resolution affecting apps. This is not in the
+            // UX design for v2, and there is no good place to put it, since (a) if it is on the
+            // bottom of the screen, the external resolution setting must be below the built-in
+            // display options for the per-display fragment, which is too hidden for the per-display
+            // fragment, or (b) the footer is above the Built-in display settings, rather than the
+            // bottom of the screen, which contradicts the visual style and purpose of the
+            // FooterPreference class, or (c) we must hide the built-in display settings, which is
+            // inconsistent with the topology pane, which shows that display.
+            // TODO(b/352648432): probably remove footer once the pane and rest of v2 UI is in
+            // place.
+            if (!isTopologyPaneEnabled(mInjector)) {
                 screen.addPreference(updateFooterPreference(context,
                         EXTERNAL_DISPLAY_CHANGE_RESOLUTION_FOOTER_RESOURCE));
             }
+        }
         if (isDisplaySizeSettingEnabled(mInjector)) {
             screen.addPreference(updateSizePreference(context));
         }
     }
 
-    private void showDisplaysList(@NonNull List<Display> displaysToShow,
+    private void maybeAddV2Components(Context context, PrefRefresh screen) {
-                                  @NonNull PrefRefresh screen, @NonNull Context context) {
         if (isTopologyPaneEnabled(mInjector)) {
             screen.addPreference(getDisplayTopologyPreference(context));
-            if (!displaysToShow.isEmpty()) {
             screen.addPreference(getMirrorPreference(context));
-            }
 
             // If topology is shown, we also show a preference for the built-in display for
             // consistency with the topology.
@@ -468,7 +503,11 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
             screen.addPreference(builtinCategory);
             builtinCategory.addPreference(getBuiltinDisplaySizeAndTextPreference(context));
         }
+    }
 
+    private void showDisplaysList(@NonNull List<Display> displaysToShow,
+                                  @NonNull PrefRefresh screen, @NonNull Context context) {
+        maybeAddV2Components(context, screen);
         var displayGroupPref = getDisplaysListPreference(context);
         if (!displaysToShow.isEmpty()) {
             screen.addPreference(displayGroupPref);
@@ -501,8 +540,9 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
             groupCleanable.addPreference(category);
 
             var prefItem = new DisplayPreference(context, display);
-            prefItem.setTitle(context.getString(EXTERNAL_DISPLAY_RESOLUTION_TITLE_RESOURCE)
+            prefItem.setTitle(
-                    + " | " + context.getString(EXTERNAL_DISPLAY_ROTATION_TITLE_RESOURCE));
+                    context.getString(PrefBasics.EXTERNAL_DISPLAY_RESOLUTION.titleResource) + " | "
+                    + context.getString(PrefBasics.EXTERNAL_DISPLAY_ROTATION.titleResource));
             prefItem.setKey(itemKey);
 
             category.addPreference(prefItem);
@@ -577,6 +617,7 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
     private Preference updateFooterPreference(@NonNull final Context context, final int title) {
         var pref = getFooterPreference(context);
         pref.setTitle(title);
+        PrefBasics.FOOTER.apply(pref);
         return pref;
     }
 
@@ -625,10 +666,8 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
 
     private Preference updateSizePreference(@NonNull final Context context) {
         var pref = (Preference) getSizePreference(context);
-        pref.setKey(EXTERNAL_DISPLAY_SIZE_PREFERENCE_KEY);
+        PrefBasics.EXTERNAL_DISPLAY_SIZE.apply(pref);
         pref.setSummary(EXTERNAL_DISPLAY_SIZE_SUMMARY_RESOURCE);
-        pref.setPersistent(false);
-        pref.setTitle(EXTERNAL_DISPLAY_SIZE_TITLE_RESOURCE);
         pref.setOnPreferenceClickListener(
                 (Preference p) -> {
                     writePreferenceClickMetric(p);

src/com/android/settings/connecteddevice/display/Mirroring.kt

@@ -23,8 +23,6 @@ import androidx.preference.SwitchPreferenceCompat
 
 import com.android.settings.R
 
-const val MIRROR_PREFERENCE_KEY = "mirror_builtin_display"
-
 /**
  * A switch preference which is backed by the MIRROR_BUILT_IN_DISPLAY global setting.
  */
@@ -32,7 +30,6 @@ class MirrorPreference(context: Context): SwitchPreferenceCompat(context) {
     init {
         setTitle(R.string.external_display_mirroring_title)
 
-        key = MIRROR_PREFERENCE_KEY
         isPersistent = false
     }
 

tests/unit/src/com/android/settings/connecteddevice/display/ExternalDisplayPreferenceFragmentTest.java

@@ -17,19 +17,10 @@ package com.android.settings.connecteddevice.display;
 
 import static android.view.Display.INVALID_DISPLAY;
 
-import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.DISPLAYS_LIST_PREFERENCE_KEY;
 import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_CHANGE_RESOLUTION_FOOTER_RESOURCE;
 import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_NOT_FOUND_FOOTER_RESOURCE;
-import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_RESOLUTION_PREFERENCE_KEY;
-import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_RESOLUTION_TITLE_RESOURCE;
-import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_ROTATION_KEY;
-import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_ROTATION_TITLE_RESOURCE;
 import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_SETTINGS_RESOURCE;
-import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_SIZE_PREFERENCE_KEY;
 import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_SIZE_SUMMARY_RESOURCE;
-import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_SIZE_TITLE_RESOURCE;
-import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_USE_PREFERENCE_KEY;
-import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_USE_TITLE_RESOURCE;
 import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.PREVIOUSLY_SHOWN_LIST_KEY;
 import static com.android.settings.flags.Flags.FLAG_DISPLAY_SIZE_CONNECTED_DISPLAY_SETTING;
 import static com.android.settings.flags.Flags.FLAG_DISPLAY_TOPOLOGY_PANE_IN_DISPLAY_LIST;
@@ -61,6 +52,7 @@ import androidx.test.annotation.UiThreadTest;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 
 import com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.DisplayPreference;
+import com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.PrefBasics;
 import com.android.settingslib.widget.FooterPreference;
 import com.android.settingslib.widget.MainSwitchPreference;
 
@@ -97,23 +89,22 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         fragment.onSaveInstanceStateCallback(outState);
         assertThat(outState.getBoolean(PREVIOUSLY_SHOWN_LIST_KEY)).isFalse();
         assertThat(mHandler.getPendingMessages().size()).isEqualTo(1);
-        PreferenceCategory pref = mPreferenceScreen.findPreference(DISPLAYS_LIST_PREFERENCE_KEY);
+        PreferenceCategory pref = mPreferenceScreen.findPreference(PrefBasics.DISPLAYS_LIST.key);
         assertThat(pref).isNull();
         verify(mMockedInjector, never()).getAllDisplays();
         mHandler.flush();
         assertThat(mHandler.getPendingMessages().size()).isEqualTo(0);
         verify(mMockedInjector).getAllDisplays();
-        pref = mPreferenceScreen.findPreference(DISPLAYS_LIST_PREFERENCE_KEY);
+        pref = mPreferenceScreen.findPreference(PrefBasics.DISPLAYS_LIST.key);
         assertThat(pref).isNotNull();
         assertThat(pref.getPreferenceCount()).isEqualTo(2);
         fragment.onSaveInstanceStateCallback(outState);
         assertThat(outState.getBoolean(PREVIOUSLY_SHOWN_LIST_KEY)).isTrue();
 
-        pref = mPreferenceScreen.findPreference(DisplayTopologyKt.TOPOLOGY_PREFERENCE_KEY);
+        pref = mPreferenceScreen.findPreference(PrefBasics.DISPLAY_TOPOLOGY.key);
         assertThat(pref).isNull();
 
-        pref = mPreferenceScreen.findPreference(
+        pref = mPreferenceScreen.findPreference(PrefBasics.BUILTIN_DISPLAY_LIST.key);
-                ExternalDisplayPreferenceFragment.BUILTIN_DISPLAY_LIST_PREFERENCE_KEY);
         assertThat(pref).isNull();
     }
 
@@ -126,56 +117,51 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         doReturn(new Display[] {mDisplays[1]}).when(mMockedInjector).getAllDisplays();
         mHandler.flush();
 
-        var pref = mPreferenceScreen.findPreference(DisplayTopologyKt.TOPOLOGY_PREFERENCE_KEY);
+        var pref = mPreferenceScreen.findPreference(PrefBasics.DISPLAY_TOPOLOGY.key);
         assertThat(pref).isNotNull();
-        pref = mPreferenceScreen.findPreference(MirroringKt.MIRROR_PREFERENCE_KEY);
+        pref = mPreferenceScreen.findPreference(PrefBasics.MIRROR.key);
         assertThat(pref).isNotNull();
 
-        PreferenceCategory listPref =
+        pref = mPreferenceScreen.findPreference(PrefBasics.DISPLAYS_LIST.key);
-                mPreferenceScreen.findPreference(DISPLAYS_LIST_PREFERENCE_KEY);
-        assertThat(listPref).isNotNull();
-        assertThat(listPref.getPreferenceCount()).isEqualTo(1);
-
-        listPref = mPreferenceScreen.findPreference(
-                ExternalDisplayPreferenceFragment.BUILTIN_DISPLAY_LIST_PREFERENCE_KEY);
-        assertThat(listPref).isNotNull();
-        assertThat(listPref.getPreferenceCount()).isEqualTo(1);
-    }
-
-    @Test
-    @UiThreadTest
-    public void testShowDisplayListWithPane_NoExternalDisplays() {
-        mFlags.setFlag(FLAG_DISPLAY_TOPOLOGY_PANE_IN_DISPLAY_LIST, true);
-
-        initFragment();
-        doReturn(new Display[0]).when(mMockedInjector).getAllDisplays();
-        mHandler.flush();
-
-        var pref = mPreferenceScreen.findPreference(DisplayTopologyKt.TOPOLOGY_PREFERENCE_KEY);
-        assertThat(pref).isNotNull();
-        pref = mPreferenceScreen.findPreference(MirroringKt.MIRROR_PREFERENCE_KEY);
         assertThat(pref).isNull();
 
         PreferenceCategory listPref =
-                mPreferenceScreen.findPreference(DISPLAYS_LIST_PREFERENCE_KEY);
+                mPreferenceScreen.findPreference(PrefBasics.BUILTIN_DISPLAY_LIST.key);
-        assertThat(listPref).isNull();
-
-        listPref = mPreferenceScreen.findPreference(
-                ExternalDisplayPreferenceFragment.BUILTIN_DISPLAY_LIST_PREFERENCE_KEY);
-        assertThat(listPref).isNotNull();
-        assertThat(listPref.getPreferenceCount()).isEqualTo(1);
         var builtinPref = listPref.getPreference(0);
         assertThat(builtinPref.getOnPreferenceClickListener().onPreferenceClick(builtinPref))
                 .isTrue();
         assertThat(mLaunchedBuiltinSettings).isTrue();
     }
 
+    @Test
+    @UiThreadTest
+    public void testDontShowDisplayListOrPane_NoExternalDisplays() {
+        mFlags.setFlag(FLAG_DISPLAY_TOPOLOGY_PANE_IN_DISPLAY_LIST, true);
+
+        initFragment();
+        doReturn(new Display[0]).when(mMockedInjector).getAllDisplays();
+        mHandler.flush();
+
+        // When no external display is attached, interactive preferences are omitted.
+        var pref = mPreferenceScreen.findPreference(PrefBasics.DISPLAY_TOPOLOGY.key);
+        assertThat(pref).isNull();
+        pref = mPreferenceScreen.findPreference(PrefBasics.MIRROR.key);
+        assertThat(pref).isNull();
+
+        PreferenceCategory listPref =
+                mPreferenceScreen.findPreference(PrefBasics.DISPLAYS_LIST.key);
+        assertThat(listPref).isNull();
+
+        listPref = mPreferenceScreen.findPreference(PrefBasics.BUILTIN_DISPLAY_LIST.key);
+        assertThat(listPref).isNull();
+    }
+
     @Test
     @UiThreadTest
     public void testLaunchDisplaySettingFromList() {
         initFragment();
         mHandler.flush();
-        PreferenceCategory pref = mPreferenceScreen.findPreference(DISPLAYS_LIST_PREFERENCE_KEY);
+        PreferenceCategory pref = mPreferenceScreen.findPreference(PrefBasics.DISPLAYS_LIST.key);
         assertThat(pref).isNotNull();
         var display1Category = (PreferenceCategory) pref.getPreference(0);
         var display1Pref = (DisplayPreference) display1Category.getPreference(0);
@@ -204,7 +190,7 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         // Only one display available
         doReturn(new Display[] {mDisplays[1]}).when(mMockedInjector).getAllDisplays();
         mHandler.flush();
-        PreferenceCategory pref = mPreferenceScreen.findPreference(DISPLAYS_LIST_PREFERENCE_KEY);
+        PreferenceCategory pref = mPreferenceScreen.findPreference(PrefBasics.DISPLAYS_LIST.key);
         assertThat(pref).isNotNull();
         assertThat(pref.getPreferenceCount()).isEqualTo(1);
     }
@@ -219,15 +205,15 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         // Init
         initFragment();
         mHandler.flush();
-        PreferenceCategory list = mPreferenceScreen.findPreference(DISPLAYS_LIST_PREFERENCE_KEY);
+        PreferenceCategory list = mPreferenceScreen.findPreference(PrefBasics.DISPLAYS_LIST.key);
         assertThat(list).isNull();
-        var pref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_RESOLUTION_PREFERENCE_KEY);
+        var pref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_RESOLUTION.key);
         assertThat(pref).isNotNull();
-        pref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_ROTATION_KEY);
+        pref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_ROTATION.key);
         assertThat(pref).isNotNull();
         var footerPref = (FooterPreference) mPreferenceScreen.findPreference(KEY_FOOTER);
         assertThat(footerPref).isNotNull();
-        var sizePref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_SIZE_PREFERENCE_KEY);
+        var sizePref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_SIZE.key);
         assertThat(sizePref).isNull();
         verify(footerPref).setTitle(EXTERNAL_DISPLAY_CHANGE_RESOLUTION_FOOTER_RESOURCE);
     }
@@ -241,15 +227,15 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         // Init
         initFragment();
         mHandler.flush();
-        PreferenceCategory list = mPreferenceScreen.findPreference(DISPLAYS_LIST_PREFERENCE_KEY);
+        PreferenceCategory list = mPreferenceScreen.findPreference(PrefBasics.DISPLAYS_LIST.key);
         assertThat(list).isNull();
-        var pref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_RESOLUTION_PREFERENCE_KEY);
+        var pref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_RESOLUTION.key);
         assertThat(pref).isNotNull();
-        pref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_ROTATION_KEY);
+        pref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_ROTATION.key);
         assertThat(pref).isNotNull();
         var footerPref = (FooterPreference) mPreferenceScreen.findPreference(KEY_FOOTER);
         assertThat(footerPref).isNotNull();
-        var sizePref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_SIZE_PREFERENCE_KEY);
+        var sizePref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_SIZE.key);
         assertThat(sizePref).isNotNull();
         verify(footerPref).setTitle(EXTERNAL_DISPLAY_CHANGE_RESOLUTION_FOOTER_RESOURCE);
     }
@@ -263,13 +249,13 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         verify(mMockedInjector, never()).getDisplay(anyInt());
         mHandler.flush();
         verify(mMockedInjector).getDisplay(mDisplayIdArg);
-        var pref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_RESOLUTION_PREFERENCE_KEY);
+        var pref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_RESOLUTION.key);
         assertThat(pref).isNotNull();
-        pref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_ROTATION_KEY);
+        pref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_ROTATION.key);
         assertThat(pref).isNotNull();
         var footerPref = (FooterPreference) mPreferenceScreen.findPreference(KEY_FOOTER);
         assertThat(footerPref).isNotNull();
-        var sizePref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_SIZE_PREFERENCE_KEY);
+        var sizePref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_SIZE.key);
         assertThat(sizePref).isNotNull();
         verify(footerPref).setTitle(EXTERNAL_DISPLAY_CHANGE_RESOLUTION_FOOTER_RESOURCE);
     }
@@ -283,20 +269,20 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         mHandler.flush();
         verify(mMockedInjector).getDisplay(mDisplayIdArg);
         var mainPref = (MainSwitchPreference) mPreferenceScreen.findPreference(
-                EXTERNAL_DISPLAY_USE_PREFERENCE_KEY);
+                PrefBasics.EXTERNAL_DISPLAY_USE.key);
         assertThat(mainPref).isNotNull();
         assertThat("" + mainPref.getTitle()).isEqualTo(
-                getText(EXTERNAL_DISPLAY_USE_TITLE_RESOURCE));
+                getText(PrefBasics.EXTERNAL_DISPLAY_USE.titleResource));
         assertThat(mainPref.isChecked()).isFalse();
         assertThat(mainPref.isEnabled()).isTrue();
         assertThat(mainPref.getOnPreferenceChangeListener()).isNotNull();
-        var pref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_RESOLUTION_PREFERENCE_KEY);
+        var pref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_RESOLUTION.key);
         assertThat(pref).isNull();
-        pref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_ROTATION_KEY);
+        pref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_ROTATION.key);
         assertThat(pref).isNull();
         var footerPref = (FooterPreference) mPreferenceScreen.findPreference(KEY_FOOTER);
         assertThat(footerPref).isNull();
-        var sizePref = mPreferenceScreen.findPreference(EXTERNAL_DISPLAY_SIZE_PREFERENCE_KEY);
+        var sizePref = mPreferenceScreen.findPreference(PrefBasics.EXTERNAL_DISPLAY_SIZE.key);
         assertThat(sizePref).isNull();
     }
 
@@ -307,10 +293,10 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         initFragment();
         mHandler.flush();
         var mainPref = (MainSwitchPreference) mPreferenceScreen.findPreference(
-                EXTERNAL_DISPLAY_USE_PREFERENCE_KEY);
+                PrefBasics.EXTERNAL_DISPLAY_USE.key);
         assertThat(mainPref).isNotNull();
         assertThat("" + mainPref.getTitle()).isEqualTo(
-                getText(EXTERNAL_DISPLAY_USE_TITLE_RESOURCE));
+                getText(PrefBasics.EXTERNAL_DISPLAY_USE.titleResource));
         assertThat(mainPref.isChecked()).isFalse();
         assertThat(mainPref.isEnabled()).isFalse();
         assertThat(mainPref.getOnPreferenceChangeListener()).isNull();
@@ -327,9 +313,9 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         var fragment = initFragment();
         mHandler.flush();
         var pref = fragment.getRotationPreference(mContext);
-        assertThat(pref.getKey()).isEqualTo(EXTERNAL_DISPLAY_ROTATION_KEY);
+        assertThat(pref.getKey()).isEqualTo(PrefBasics.EXTERNAL_DISPLAY_ROTATION.key);
         assertThat("" + pref.getTitle()).isEqualTo(
-                getText(EXTERNAL_DISPLAY_ROTATION_TITLE_RESOURCE));
+                getText(PrefBasics.EXTERNAL_DISPLAY_ROTATION.titleResource));
         assertThat(pref.getEntries().length).isEqualTo(4);
         assertThat(pref.getEntryValues().length).isEqualTo(4);
         assertThat(pref.getEntryValues()[0].toString()).isEqualTo("0");
@@ -359,9 +345,9 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         var fragment = initFragment();
         mHandler.flush();
         var pref = fragment.getResolutionPreference(mContext);
-        assertThat(pref.getKey()).isEqualTo(EXTERNAL_DISPLAY_RESOLUTION_PREFERENCE_KEY);
+        assertThat(pref.getKey()).isEqualTo(PrefBasics.EXTERNAL_DISPLAY_RESOLUTION.key);
         assertThat("" + pref.getTitle()).isEqualTo(
-                getText(EXTERNAL_DISPLAY_RESOLUTION_TITLE_RESOURCE));
+                getText(PrefBasics.EXTERNAL_DISPLAY_RESOLUTION.titleResource));
         assertThat("" + pref.getSummary()).isEqualTo("1920 x 1080");
         assertThat(pref.isEnabled()).isTrue();
         assertThat(pref.getOnPreferenceClickListener()).isNotNull();
@@ -378,8 +364,9 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         var fragment = initFragment();
         mHandler.flush();
         var pref = fragment.getSizePreference(mContext);
-        assertThat(pref.getKey()).isEqualTo(EXTERNAL_DISPLAY_SIZE_PREFERENCE_KEY);
+        assertThat(pref.getKey()).isEqualTo(PrefBasics.EXTERNAL_DISPLAY_SIZE.key);
-        assertThat("" + pref.getTitle()).isEqualTo(getText(EXTERNAL_DISPLAY_SIZE_TITLE_RESOURCE));
+        assertThat("" + pref.getTitle())
+                .isEqualTo(getText(PrefBasics.EXTERNAL_DISPLAY_SIZE.titleResource));
         assertThat("" + pref.getSummary())
                 .isEqualTo(getText(EXTERNAL_DISPLAY_SIZE_SUMMARY_RESOURCE));
         assertThat(pref.isEnabled()).isTrue();
@@ -398,8 +385,9 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         var fragment = initFragment();
         mHandler.flush();
         var pref = fragment.getUseDisplayPreference(mContext);
-        assertThat(pref.getKey()).isEqualTo(EXTERNAL_DISPLAY_USE_PREFERENCE_KEY);
+        assertThat(pref.getKey()).isEqualTo(PrefBasics.EXTERNAL_DISPLAY_USE.key);
-        assertThat("" + pref.getTitle()).isEqualTo(getText(EXTERNAL_DISPLAY_USE_TITLE_RESOURCE));
+        assertThat("" + pref.getTitle())
+                .isEqualTo(getText(PrefBasics.EXTERNAL_DISPLAY_USE.titleResource));
         assertThat(pref.isEnabled()).isTrue();
         assertThat(pref.isChecked()).isTrue();
         assertThat(pref.getOnPreferenceChangeListener()).isNotNull();