Topology pane in extended displays list

Show an empty topology pane in the extended displays list. Even show
when no external display is connected.

This will be tweaked in a follow-up CL to include the built-in display
in the pane and the displays list.

This fixes an issue where the displays list is not shown when *no*
external displays are connected, which was not the intent of the flag.
The previous flag CL ag/30358161 only respected the flag when 1 external
display was connected.

Based on mocks at go/al-mm-figma

Bug: b/352650922
Test: reboot with zero displays attached and verify display list and pane are shown
Test: on al-13 device, make the activity fullscreen and verify the margins on left and right of pane are larger
Flag: com.android.settings.flags.display_topology_pane_in_display_list
Change-Id: If39fefe943a26c817fa6f636f21eb8aaa080adde

res/drawable/display_topology_background.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2024 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+<inset xmlns:android="http://schemas.android.com/apk/res/android">
+    <shape android:shape="rectangle">
+        <corners android:radius="?android:attr/dialogCornerRadius" />
+        <solid android:color="@color/display_topology_background_color" />
+    </shape>
+</inset>

res/layout/display_topology_preference.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2024 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+<FrameLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:importantForAccessibility="no"
+    android:layout_height="160dp"
+    android:layout_width="match_parent"
+    android:paddingHorizontal="@dimen/display_topology_pane_margin"
+    android:orientation="horizontal">
+    <ImageView
+        android:importantForAccessibility="no"
+        android:layout_height="match_parent"
+        android:layout_width="match_parent"
+        android:src="@drawable/display_topology_background"/>
+    <FrameLayout
+        android:id="@+id/display_topology_container"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"/>
+    <TextView
+        android:id="@+id/topology_hint"
+        android:layout_height="wrap_content"
+        android:layout_width="wrap_content"
+        android:layout_gravity="top|center_horizontal"
+        android:paddingTop="10dp"
+        android:text="@string/external_display_topology_hint"/>
+</FrameLayout>

res/values-land/dimens.xml

@@ -30,4 +30,7 @@
 
     <!-- Keyboard -->
     <dimen name="keyboard_picker_margin">106dp</dimen>
+
+    <!-- Connected displays -->
+    <dimen name="display_topology_pane_margin">80dp</dimen>
 </resources>

res/values-night/colors.xml

@@ -79,5 +79,8 @@
 
     <!-- Pointer fill color setting outline color-->
     <color name="pointer_fill_outline_color">#FFFFFF</color>
+
+    <!-- Connected displays -->
+    <color name="display_topology_background_color">@color/settingslib_color_charcoal</color>
 </resources>
 

res/values/colors.xml

@@ -221,4 +221,7 @@
 
     <!-- Pointer fill color setting outline color-->
     <color name="pointer_fill_outline_color">#000000</color>
+
+    <!-- Connected displays -->
+    <color name="display_topology_background_color">@color/settingslib_color_grey100</color>
 </resources>

res/values/dimens.xml

@@ -539,4 +539,7 @@
     <dimen name="zen_mode_circular_icon_margin_between">4dp</dimen>
     <dimen name="zen_mode_circular_icon_margin_vertical">8dp</dimen>
     <dimen name="zen_mode_circular_icon_text_size">18dp</dimen>
+
+    <!-- Connected displays -->
+    <dimen name="display_topology_pane_margin">24dp</dimen>
 </resources>

res/values/strings.xml

@@ -2027,6 +2027,8 @@
     <string name="external_display_not_found_footer_title">Your device must be connected to an external display to mirror your screen</string>
     <!-- External Display settings. More resolution options -->
     <string name="external_display_more_options_title">More options</string>
+    <!-- External Display settings. -->
+    <string name="external_display_topology_hint">Hold and drag to rearrange displays.</string>
 
     <!-- Wifi Display settings. The title of the screen. [CHAR LIMIT=40] -->
     <string name="wifi_display_settings_title">Cast</string>

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

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.connecteddevice.display
+
+import com.android.settings.R
+
+import android.content.Context
+
+import androidx.preference.Preference
+
+const val PREFERENCE_KEY = "display_topology_preference"
+
+/**
+ * DisplayTopologyPreference allows the user to change the display topology
+ * when there is one or more extended display attached.
+ */
+class DisplayTopologyPreference(context : Context) : Preference(context) {
+    init {
+        layoutResource = R.layout.display_topology_preference
+
+        // Prevent highlight when hovering with mouse.
+        isSelectable = false
+
+        key = PREFERENCE_KEY
+    }
+}

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

@@ -97,6 +97,8 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
     @Nullable
     private FooterPreference mFooterPreference;
     @Nullable
+    private Preference mDisplayTopologyPreference;
+    @Nullable
     private PreferenceCategory mDisplaysPreference;
     @Nullable
     private Injector mInjector;
@@ -279,6 +281,14 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
         return mDisplaysPreference;
     }
 
+    @NonNull Preference getDisplayTopologyPreference(@NonNull Context context) {
+        if (mDisplayTopologyPreference == null) {
+            mDisplayTopologyPreference = new DisplayTopologyPreference(context);
+            mDisplayTopologyPreference.setPersistent(false);
+        }
+        return mDisplayTopologyPreference;
+    }
+
     private void restoreState(@Nullable Bundle savedInstanceState) {
         if (savedInstanceState == null) {
             return;
@@ -296,20 +306,16 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
         updateScreenForDisplayId(getDisplayIdArg(), screen, mInjector.getContext());
     }
 
-    private boolean okayToBypassDisplayListSelection() {
-        if (mInjector != null && forceShowDisplayList(mInjector.getFlags())) {
-            return false;
-        }
-        return !mPreviouslyShownListOfDisplays;
-    }
-
     private void updateScreenForDisplayId(final int displayId,
             @NonNull final PreferenceScreen screen, @NonNull Context context) {
+        final boolean forceShowList = displayId == INVALID_DISPLAY
+                && mInjector != null && forceShowDisplayList(mInjector.getFlags());
         final var displaysToShow = getDisplaysToShow(displayId);
-        if (displaysToShow.isEmpty() && displayId == INVALID_DISPLAY) {
+
+        if (!forceShowList && displaysToShow.isEmpty() && displayId == INVALID_DISPLAY) {
             showTextWhenNoDisplaysToShow(screen, context);
-        } else if (displaysToShow.size() == 1
+        } else if (!forceShowList && displaysToShow.size() == 1
-                && ((displayId == INVALID_DISPLAY && okayToBypassDisplayListSelection())
+                && ((displayId == INVALID_DISPLAY && !mPreviouslyShownListOfDisplays)
                         || displaysToShow.get(0).getDisplayId() == displayId)) {
             showDisplaySettings(displaysToShow.get(0), screen, context);
         } else if (displayId == INVALID_DISPLAY) {
@@ -367,6 +373,11 @@ public class ExternalDisplayPreferenceFragment extends SettingsPreferenceFragmen
 
     private void showDisplaysList(@NonNull List<Display> displaysToShow,
             @NonNull PreferenceScreen screen, @NonNull Context context) {
+        if (mInjector != null
+                && mInjector.getFlags().displayTopologyPaneInDisplayList()) {
+            screen.addPreference(getDisplayTopologyPreference(context));
+        }
+
         var pref = getDisplaysListPreference(context);
         pref.setKey(DISPLAYS_LIST_PREFERENCE_KEY);
         pref.removeAll();

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

@@ -15,7 +15,6 @@
  */
 package com.android.settings.connecteddevice.display;
 
-
 import static android.view.Display.INVALID_DISPLAY;
 
 import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.PREVIOUSLY_SHOWN_LIST_KEY;
@@ -29,6 +28,7 @@ import static com.android.settings.connecteddevice.display.ExternalDisplayPrefer
 import static com.android.settings.connecteddevice.display.ExternalDisplayPreferenceFragment.EXTERNAL_DISPLAY_SETTINGS_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.flags.Flags.FLAG_DISPLAY_TOPOLOGY_PANE_IN_DISPLAY_LIST;
 import static com.android.settingslib.widget.FooterPreference.KEY_FOOTER;
 
 import static com.google.common.truth.Truth.assertThat;
@@ -85,6 +85,8 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
     @Test
     @UiThreadTest
     public void testShowDisplayList() {
+        mFlags.setFlag(FLAG_DISPLAY_TOPOLOGY_PANE_IN_DISPLAY_LIST, false);
+
         var fragment = initFragment();
         var outState = new Bundle();
         fragment.onSaveInstanceStateCallback(outState);
@@ -101,6 +103,46 @@ public class ExternalDisplayPreferenceFragmentTest extends ExternalDisplayTestBa
         assertThat(pref.getPreferenceCount()).isEqualTo(2);
         fragment.onSaveInstanceStateCallback(outState);
         assertThat(outState.getBoolean(PREVIOUSLY_SHOWN_LIST_KEY)).isTrue();
+
+        pref = mPreferenceScreen.findPreference(DisplayTopologyKt.PREFERENCE_KEY);
+        assertThat(pref).isNull();
+    }
+
+    @Test
+    @UiThreadTest
+    public void testShowDisplayListWithPane_OneExternalDisplay() {
+        mFlags.setFlag(FLAG_DISPLAY_TOPOLOGY_PANE_IN_DISPLAY_LIST, true);
+
+        initFragment();
+        doReturn(new Display[] {mDisplays[1]}).when(mMockedInjector).getAllDisplays();
+        mHandler.flush();
+
+        var pref = mPreferenceScreen.findPreference(DisplayTopologyKt.PREFERENCE_KEY);
+        assertThat(pref).isNotNull();
+
+        PreferenceCategory listPref =
+                mPreferenceScreen.findPreference(DISPLAYS_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.PREFERENCE_KEY);
+        assertThat(pref).isNotNull();
+
+        // TODO: add the built-in display to the list, which will cause this preference to not be
+        // null.
+        PreferenceCategory listPref =
+                mPreferenceScreen.findPreference(DISPLAYS_LIST_PREFERENCE_KEY);
+        assertThat(listPref).isNull();
     }
 
     @Test