Improve the performance of displaying preference.

- Set a variable to record the status then replace getAvailabilityStatus() with it.

Test: manual test, use command to run MobileNetworkSettings and record it.
Bug: 154061428
Merged-In: Ia13a75a3821bb6c17d0dfeffb5043f47b60adf61
Change-Id: Ia13a75a3821bb6c17d0dfeffb5043f47b60adf61

src/com/android/settings/network/telephony/TelephonyAvailabilityHandler.java

@@ -0,0 +1,38 @@
+/*
+ * 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.
+ */
+
+/**
+ * Interface letting {@link TelephonyTogglePreferenceController and
+ * @link TelephonyBasePreferenceController} can handle availability status.
+ */
+package com.android.settings.network.telephony;
+
+import android.content.Context;
+
+public interface TelephonyAvailabilityHandler {
+
+    /**
+     * Set availability to preference controller.
+     */
+    public void setAvailabilityStatus(int status);
+
+    /**
+     * Do not set availability, use
+     * {@link MobileNetworkUtils#getAvailability(Context, int, TelephonyAvailabilityCallback)}
+     * to get the availability.
+     */
+    public void unsetAvailabilityStatus(boolean enable);
+}