Add a CMSystemSettingDropDownPreference.

Change-Id: Ic3b7589fe3a33b62fba3949e968789a3a99cf9f6

sdk/src/java/cyanogenmod/preference/CMSystemSettingDropDownPreference.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2016 The CyanogenMod 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 cyanogenmod.preference;
+
+import android.content.Context;
+import android.util.AttributeSet;
+
+import cyanogenmod.providers.CMSettings;
+
+
+public class CMSystemSettingDropDownPreference extends SelfRemovingDropDownPreference {
+    public CMSystemSettingDropDownPreference(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+    }
+
+    public CMSystemSettingDropDownPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    protected boolean persistString(String value) {
+        if (shouldPersist()) {
+            if (value == getPersistedString(null)) {
+                // It's already there, so the same as persisting
+                return true;
+            }
+            CMSettings.System.putString(getContext().getContentResolver(), getKey(), value);
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    protected String getPersistedString(String defaultReturnValue) {
+        if (!shouldPersist()) {
+            return defaultReturnValue;
+        }
+        String value = CMSettings.System.getString(getContext().getContentResolver(), getKey());
+        return value == null ? defaultReturnValue : value;
+    }
+
+    @Override
+    protected boolean isPersisted() {
+        return CMSettings.System.getString(getContext().getContentResolver(), getKey()) != null;
+    }
+
+    public int getIntValue(int defValue) {
+        return getValue() == null ? defValue : Integer.valueOf(getValue());
+    }
+}

sdk/src/java/cyanogenmod/preference/SelfRemovingDropDownPreference.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2016 The CyanogenMod 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 cyanogenmod.preference;
+
+import android.content.Context;
+import android.support.v7.preference.DropDownPreference;
+import android.support.v7.preference.PreferenceViewHolder;
+import android.util.AttributeSet;
+
+/**
+ * A Preference which can automatically remove itself from the hierarchy
+ * based on constraints set in XML.
+ */
+public class SelfRemovingDropDownPreference extends DropDownPreference {
+
+    private final ConstraintsHelper mConstraints;
+
+    public SelfRemovingDropDownPreference(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        mConstraints = new ConstraintsHelper(context, attrs, this);
+    }
+
+    public SelfRemovingDropDownPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        mConstraints = new ConstraintsHelper(context, attrs, this);
+    }
+
+    public SelfRemovingDropDownPreference(Context context) {
+        super(context);
+        mConstraints = new ConstraintsHelper(context, null, this);
+    }
+
+    @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();
+    }
+}