feat(#MagnificationJoystick): add preference for enabling Joystick to Settings

Hide behind feature flag so no one sees the preference unless its enabled.

Bug: b/265688847

Test: atest MagnificationJoystickPreferenceControllerTest

Change-Id: Id5cc9385f25395f53809a79ba70c84205f9758c2

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

@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2022 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 static com.android.settings.accessibility.AccessibilityUtil.State.OFF;
+import static com.android.settings.accessibility.AccessibilityUtil.State.ON;
+
+import android.content.Context;
+import android.provider.Settings;
+
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.LifecycleObserver;
+import androidx.lifecycle.OnLifecycleEvent;
+import androidx.preference.PreferenceScreen;
+import androidx.preference.SwitchPreference;
+
+import com.android.settings.R;
+import com.android.settings.core.TogglePreferenceController;
+
+/**
+ * Controller that accesses and switches the preference status of the magnification joystick feature
+ */
+public class MagnificationJoystickPreferenceController extends TogglePreferenceController
+        implements LifecycleObserver {
+
+    private static final String TAG =
+            MagnificationJoystickPreferenceController.class.getSimpleName();
+    static final String PREF_KEY = Settings.Secure.ACCESSIBILITY_MAGNIFICATION_JOYSTICK_ENABLED;
+
+    private SwitchPreference mSwitchPreference;
+
+    public MagnificationJoystickPreferenceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+
+    @Override
+    public boolean isChecked() {
+        return Settings.Secure.getInt(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_MAGNIFICATION_JOYSTICK_ENABLED, OFF) == ON;
+    }
+
+    @Override
+    public boolean setChecked(boolean isChecked) {
+        return Settings.Secure.putInt(mContext.getContentResolver(),
+                Settings.Secure.ACCESSIBILITY_MAGNIFICATION_JOYSTICK_ENABLED,
+                (isChecked ? ON : OFF));
+    }
+
+    @Override
+    public int getSliceHighlightMenuRes() {
+        return R.string.menu_key_accessibility;
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+        mSwitchPreference = screen.findPreference(getPreferenceKey());
+    }
+
+    // TODO(b/186731461): Remove it when this controller is used in DashBoardFragment only.
+    @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
+    void onResume() {
+        updateState();
+    }
+
+    /**
+     * Updates the state of preference components which has been displayed by
+     * {@link MagnificationJoystickPreferenceController#displayPreference}.
+     */
+    void updateState() {
+        updateState(mSwitchPreference);
+    }
+}