Add accessibility shortcuts fragment in a11y settings

Accessibility settings category restructure, add accessibility shortcuts
fragment for related accessibility services.

Bug: 174829936
Test: atest AccessibilityShortcutsFragmentTest, atest AccessibilitySettingsTest
Change-Id: I9706906863872bc60d31eae54bbf3a35d70e812e

src/com/android/settings/accessibility/AccessibilitySettings.java

@@ -372,6 +372,9 @@ public class AccessibilitySettings extends DashboardFragment {
         } else {
             getPreferenceScreen().addPreference(downloadedServicesCategory);
         }
+
+        // Hide screen reader category if it is empty.
+        updatePreferenceCategoryVisibility(CATEGORY_SCREEN_READER);
     }
 
     private List<RestrictedPreference> getInstalledAccessibilityList(Context context) {
@@ -452,6 +455,16 @@ public class AccessibilitySettings extends DashboardFragment {
         }
     }
 
+    /**
+     * Updates the visibility of a category according to its child preference count.
+     *
+     * @param categoryKey The key of the category which needs to check
+     */
+    private void updatePreferenceCategoryVisibility(String categoryKey) {
+        final PreferenceCategory category = mCategoryToPrefCategoryMap.get(categoryKey);
+        category.setVisible(category.getPreferenceCount() != 0);
+    }
+
     /**
      * Updates preferences related to system configurations.
      */

src/com/android/settings/accessibility/ShortcutsSettingsFragment.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2021 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.accessibility;
+
+import android.app.settings.SettingsEnums;
+
+import com.android.settings.R;
+import com.android.settings.dashboard.DashboardFragment;
+import com.android.settings.search.BaseSearchIndexProvider;
+
+/** Accessibility settings for accessibility shortcuts. */
+public class ShortcutsSettingsFragment extends DashboardFragment {
+
+    private static final String TAG = "ShortcutsSettingsFragment";
+
+    @Override
+    public int getMetricsCategory() {
+        return SettingsEnums.ACCESSIBILITY_SHORTCUTS_SETTINGS;
+    }
+
+    @Override
+    protected int getPreferenceScreenResId() {
+        return R.xml.accessibility_shortcuts_settings;
+    }
+
+    @Override
+    protected String getLogTag() {
+        return TAG;
+    }
+
+    public static final BaseSearchIndexProvider SEARCH_INDEX_DATA_PROVIDER =
+            new BaseSearchIndexProvider(R.xml.accessibility_shortcuts_settings);
+
+}