[Settings] add VolteQueryImsState for IMS

1. Code refactor
2. Introduce VolteQueryImsState for user enable/disable configuration

Bug: 140542283
Test: m RunSettingsRoboTests -j ROBOTEST_FILTER=Enhanced4gBasePreferenceControllerTest
Test: m RunSettingsRoboTests -j ROBOTEST_FILTER=Enhanced4gLteSliceHelperTest
Change-Id: I9c18c8900ac01909030d9433935650c1581a0fb0

src/com/android/settings/network/ims/VolteQueryImsState.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2020 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.network.ims;
+
+import android.content.Context;
+import android.telephony.SubscriptionManager;
+
+import com.android.ims.ImsManager;
+import com.android.settings.network.SubscriptionUtil;
+
+
+/**
+ * Controller class for querying Volte status
+ */
+public class VolteQueryImsState {
+
+    private Context mContext;
+    private int mSubId;
+
+    /**
+     * Constructor
+     *
+     * @param context {@code Context}
+     * @param subId subscription's id
+     */
+    public VolteQueryImsState(Context context, int subId) {
+        mContext = context;
+        mSubId = subId;
+    }
+
+    /**
+     * Get user's configuration
+     *
+     * @return true when user's configuration is ON otherwise false.
+     */
+    public boolean isEnabledByUser() {
+        if (!SubscriptionManager.isValidSubscriptionId(mSubId)) {
+            return false;
+        }
+        ImsManager imsManager = ImsManager.getInstance(mContext, SubscriptionUtil.getPhoneId(
+                    mContext, mSubId));
+        return imsManager.isEnhanced4gLteModeSettingEnabledByUser();
+    }
+}