sdk: Introduce LineagePreferenceLib

Because of some nested dependency breakage, we can no longer include
Android libraries in main SDK lib, therefore we are moving all
preference related code to a separate package that Settings/LineageParts
will depend on.

Change-Id: Iea379a580a08ea13f71e3503aa096ba0ed7e7cef

packages/LineagePreferenceLib/java/lineageos/preference/SystemSettingSwitchPreference.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2013 The CyanogenMod Project
+ * Copyright (C) 2018 The LineageOS 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 lineageos.preference;
+
+import android.content.Context;
+import android.provider.Settings;
+import android.util.AttributeSet;
+
+public class SystemSettingSwitchPreference extends SelfRemovingSwitchPreference {
+
+    public SystemSettingSwitchPreference(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+    }
+
+    public SystemSettingSwitchPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public SystemSettingSwitchPreference(Context context) {
+        super(context, null);
+    }
+
+    @Override
+    protected boolean isPersisted() {
+        return Settings.System.getString(getContext().getContentResolver(), getKey()) != null;
+    }
+
+    @Override
+    protected void putBoolean(String key, boolean value) {
+        Settings.System.putInt(getContext().getContentResolver(), key, value ? 1 : 0);
+    }
+
+    @Override
+    protected boolean getBoolean(String key, boolean defaultValue) {
+        return Settings.System.getInt(getContext().getContentResolver(),
+                key, defaultValue ? 1 : 0) != 0;
+    }
+}