Introduce SecondaryDisplaysPreferenceController

- Create new SecondaryDisplaysPreferenceController
 - Create controller inside the DashboardFragment
 - Port logic from DevelopmentSettings into the controller

Bug: 34203528
Test: make RunSettingsRoboTests -j40
Change-Id: Ib1a7164b4e8fcf9ae8af96290d2baa33e25648f7

src/com/android/settings/development/SecondaryDisplayPreferenceController.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2017 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.development;
+
+import android.content.Context;
+import android.provider.Settings;
+import android.support.v7.preference.ListPreference;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceScreen;
+import android.text.TextUtils;
+
+import com.android.settings.R;
+import com.android.settings.core.PreferenceControllerMixin;
+import com.android.settingslib.development.DeveloperOptionsPreferenceController;
+
+public class SecondaryDisplayPreferenceController extends
+        DeveloperOptionsPreferenceController implements
+        Preference.OnPreferenceChangeListener, PreferenceControllerMixin {
+
+    private static final String OVERLAY_DISPLAY_DEVICES_KEY = "overlay_display_devices";
+
+    private final String[] mListValues;
+    private final String[] mListSummaries;
+    private ListPreference mPreference;
+
+    public SecondaryDisplayPreferenceController(Context context) {
+        super(context);
+
+        mListValues = context.getResources().getStringArray(R.array.overlay_display_devices_values);
+        mListSummaries = context.getResources().getStringArray(
+                R.array.overlay_display_devices_entries);
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return OVERLAY_DISPLAY_DEVICES_KEY;
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+
+        mPreference = (ListPreference) screen.findPreference(getPreferenceKey());
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        writeSecondaryDisplayDevicesOption(newValue.toString());
+        return true;
+    }
+
+    @Override
+    public void updateState(Preference preference) {
+        updateSecondaryDisplayDevicesOptions();
+    }
+
+    @Override
+    protected void onDeveloperOptionsSwitchEnabled() {
+        mPreference.setEnabled(true);
+    }
+
+    @Override
+    protected void onDeveloperOptionsSwitchDisabled() {
+        writeSecondaryDisplayDevicesOption(null);
+        mPreference.setEnabled(false);
+    }
+
+    private void updateSecondaryDisplayDevicesOptions() {
+        final String value = Settings.Global.getString(mContext.getContentResolver(),
+                Settings.Global.OVERLAY_DISPLAY_DEVICES);
+        int index = 0; // default
+        for (int i = 0; i < mListValues.length; i++) {
+            if (TextUtils.equals(value, mListValues[i])) {
+                index = i;
+                break;
+            }
+        }
+        mPreference.setValue(mListValues[index]);
+        mPreference.setSummary(mListSummaries[index]);
+    }
+
+    private void writeSecondaryDisplayDevicesOption(String newValue) {
+        Settings.Global.putString(mContext.getContentResolver(),
+                Settings.Global.OVERLAY_DISPLAY_DEVICES, newValue);
+        updateSecondaryDisplayDevicesOptions();
+    }
+}