Add a helper class for listening to subscription and airplane mode changes

For the new multi subscriptions UX, in several places we need to listen
for both subscription changes (eg a sim card was inserted or removed),
as well as airplane mode changing state. This combines those in one
helper class that can be reused.

Bug: 116349402
Test: make RunSettingsRoboTests
Change-Id: Ibcbb669ae291a917f89735dbda043742efaa58c9

src/com/android/settings/network/SubscriptionsChangeListener.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2018 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;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.database.ContentObserver;
+import android.net.Uri;
+import android.os.Handler;
+import android.provider.Settings;
+import android.telephony.SubscriptionManager;
+import android.telephony.SubscriptionManager.OnSubscriptionsChangedListener;
+
+import com.android.internal.telephony.TelephonyIntents;
+
+/** Helper class for listening to changes in availability of telephony subscriptions */
+public class SubscriptionsChangeListener extends ContentObserver {
+
+    public interface SubscriptionsChangeListenerClient {
+        void onAirplaneModeChanged(boolean airplaneModeEnabled);
+        void onSubscriptionsChanged();
+    }
+
+    private Context mContext;
+    private SubscriptionsChangeListenerClient mClient;
+    private SubscriptionManager mSubscriptionManager;
+    private OnSubscriptionsChangedListener mSubscriptionsChangedListener;
+    private Uri mAirplaneModeSettingUri;
+    private BroadcastReceiver mBroadcastReceiver;
+
+    public SubscriptionsChangeListener(Context context, SubscriptionsChangeListenerClient client) {
+        super(new Handler());
+        mContext = context;
+        mClient = client;
+        mSubscriptionManager = mContext.getSystemService(SubscriptionManager.class);
+        mSubscriptionsChangedListener = new OnSubscriptionsChangedListener() {
+            @Override
+            public void onSubscriptionsChanged() {
+                subscriptionsChangedCallback();
+            }
+        };
+        mAirplaneModeSettingUri = Settings.Global.getUriFor(Settings.Global.AIRPLANE_MODE_ON);
+        mBroadcastReceiver = new BroadcastReceiver() {
+            @Override
+            public void onReceive(Context context, Intent intent) {
+                subscriptionsChangedCallback();
+            }
+        };
+    }
+
+    public void start() {
+        mSubscriptionManager.addOnSubscriptionsChangedListener(mSubscriptionsChangedListener);
+        mContext.getContentResolver()
+                .registerContentObserver(mAirplaneModeSettingUri, false, this);
+        final IntentFilter radioTechnologyChangedFilter = new IntentFilter(
+                TelephonyIntents.ACTION_RADIO_TECHNOLOGY_CHANGED);
+        mContext.registerReceiver(mBroadcastReceiver, radioTechnologyChangedFilter);
+    }
+
+    public void stop() {
+        mSubscriptionManager.removeOnSubscriptionsChangedListener(mSubscriptionsChangedListener);
+        mContext.getContentResolver().unregisterContentObserver(this);
+        mContext.unregisterReceiver(mBroadcastReceiver);
+    }
+
+    public boolean isAirplaneModeOn() {
+        return Settings.Global.getInt(mContext.getContentResolver(),
+                Settings.Global.AIRPLANE_MODE_ON, 0) != 0;
+    }
+
+    private void subscriptionsChangedCallback() {
+        mClient.onSubscriptionsChanged();
+    }
+
+    @Override
+    public void onChange(boolean selfChange, Uri uri) {
+        if (uri.equals(mAirplaneModeSettingUri)) {
+            mClient.onAirplaneModeChanged(isAirplaneModeOn());
+        }
+    }
+}