Update accesibility button to suuport accessibility gesutre

1. Add gesture preference controller for gesture navigation
2. Auto update the preview illustarion when screen reader is on
3. Auto update accessibility button title for system navigation

Bug: 190563948
Test: make RunSettingsRoboTests ROBOTEST_FILTER=AccessibilityButtonGesturePreferenceControllerTest ROBOTEST_FILTER=AccessibilityButtonPreviewPreferenceControllerTest ROBOTEST_FILTER=AccessibilityLayerDrawableTest ROBOTEST_FILTER=AccessibilityPreferenceControllerTest ROBOTEST_FILTER=AccessibilityButtonFooterPreferenceControllerTest
Change-Id: Ifa98fc029430d86d3143133b3203b239340f2e41

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

@@ -0,0 +1,82 @@
+/*
+ * 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.content.Context;
+import android.provider.Settings;
+
+import androidx.preference.ListPreference;
+import androidx.preference.Preference;
+
+import com.android.settings.R;
+import com.android.settings.core.BasePreferenceController;
+
+import com.google.common.primitives.Ints;
+
+import java.util.Optional;
+
+/** Preference controller that controls the button or gesture in accessibility button page. */
+public class AccessibilityButtonGesturePreferenceController extends BasePreferenceController
+        implements Preference.OnPreferenceChangeListener {
+
+    private Optional<Integer> mDefaultGesture = Optional.empty();
+
+    public AccessibilityButtonGesturePreferenceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AccessibilityUtil.isGestureNavigateEnabled(mContext)
+                ? AVAILABLE : CONDITIONALLY_UNAVAILABLE;
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        final ListPreference listPreference = (ListPreference) preference;
+        final Integer value = Ints.tryParse((String) newValue);
+        if (value != null) {
+            Settings.Secure.putInt(mContext.getContentResolver(),
+                    Settings.Secure.ACCESSIBILITY_BUTTON_MODE, value);
+            updateState(listPreference);
+        }
+        return true;
+    }
+
+    @Override
+    public void updateState(Preference preference) {
+        super.updateState(preference);
+        final ListPreference listPreference = (ListPreference) preference;
+
+        listPreference.setValue(getCurrentAccessibilityButtonMode());
+    }
+
+    private String getCurrentAccessibilityButtonMode() {
+        final int mode = Settings.Secure.getInt(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_BUTTON_MODE, getDefaultGestureValue());
+        return String.valueOf(mode);
+    }
+
+    private int getDefaultGestureValue() {
+        if (!mDefaultGesture.isPresent()) {
+            final String[] valuesList = mContext.getResources().getStringArray(
+                    R.array.accessibility_button_gesture_selector_values);
+            mDefaultGesture = Optional.of(Integer.parseInt(valuesList[0]));
+        }
+        return mDefaultGesture.get();
+    }
+}