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/SelfRemovingSwitchPreference.java

@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2016 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.util.AttributeSet;
+
+import androidx.preference.PreferenceDataStore;
+import androidx.preference.PreferenceViewHolder;
+import androidx.preference.SwitchPreference;
+
+/**
+ * A SwitchPreference which can automatically remove itself from the hierarchy
+ * based on constraints set in XML.
+ */
+public abstract class SelfRemovingSwitchPreference extends SwitchPreference {
+
+    private final ConstraintsHelper mConstraints;
+
+    public SelfRemovingSwitchPreference(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        mConstraints = new ConstraintsHelper(context, attrs, this);
+        setPreferenceDataStore(new DataStore());
+    }
+
+    public SelfRemovingSwitchPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        mConstraints = new ConstraintsHelper(context, attrs, this);
+        setPreferenceDataStore(new DataStore());
+    }
+
+    public SelfRemovingSwitchPreference(Context context) {
+        super(context);
+        mConstraints = new ConstraintsHelper(context, null, this);
+        setPreferenceDataStore(new DataStore());
+    }
+
+    @Override
+    public void onAttached() {
+        super.onAttached();
+        mConstraints.onAttached();
+    }
+
+    @Override
+    public void onBindViewHolder(PreferenceViewHolder holder) {
+        super.onBindViewHolder(holder);
+        mConstraints.onBindViewHolder(holder);
+    }
+
+    public void setAvailable(boolean available) {
+        mConstraints.setAvailable(available);
+    }
+
+    public boolean isAvailable() {
+        return mConstraints.isAvailable();
+    }
+
+    protected abstract boolean isPersisted();
+    protected abstract void putBoolean(String key, boolean value);
+    protected abstract boolean getBoolean(String key, boolean defaultValue);
+
+    @Override
+    protected void onSetInitialValue(boolean restorePersistedValue, Object defaultValue) {
+        final boolean checked;
+        if (!restorePersistedValue || !isPersisted()) {
+            if (defaultValue == null) {
+                return;
+            }
+            checked = (boolean) defaultValue;
+            if (shouldPersist()) {
+                persistBoolean(checked);
+            }
+        } else {
+            // Note: the default is not used because to have got here
+            // isPersisted() must be true.
+            checked = getBoolean(getKey(), false /* not used */);
+        }
+        setChecked(checked);
+    }
+
+    private class DataStore extends PreferenceDataStore {
+        @Override
+        public void putBoolean(String key, boolean value) {
+            SelfRemovingSwitchPreference.this.putBoolean(key, value);
+        }
+
+        @Override
+        public boolean getBoolean(String key, boolean defaultValue) {
+            return SelfRemovingSwitchPreference.this.getBoolean(key, defaultValue);
+        }
+    }
+}