Refactor nfc preference controller

- Remove BaseNfcPreferenceController.
- NfcPreferenceController inherit from TogglePreferenceController.
- AndroidBeamPreferenceController inherit from BasePreferenceController.
- Override getIntentFilter in NfcPreferenceController to listen changes.
- Add an API (hasAsyncUpdate) into BasePreferenceController to
distinguish the setting which is updated asynchronously.

Change-Id: I1abe4410169e305a0d6106e24c54e7f2e763fc91
Merged-In: I7c9c48ea7f1ad01a02524beabf9d30baa3db891f
Fixes: 67997761
Fixes: 74887543
Test: RunSettingsRoboTests

src/com/android/settings/nfc/NfcAirplaneModeObserver.java

@@ -0,0 +1,81 @@
+/*
+ * 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.nfc;
+
+import android.content.Context;
+import android.database.ContentObserver;
+import android.net.Uri;
+import android.nfc.NfcAdapter;
+import android.os.Handler;
+import android.os.Looper;
+import android.provider.Settings;
+import android.support.annotation.VisibleForTesting;
+import android.support.v7.preference.Preference;
+
+/**
+ * NfcAirplaneModeObserver is a helper to manage the Nfc on/off when airplane mode status
+ * is changed.
+ */
+public class NfcAirplaneModeObserver extends ContentObserver {
+
+    private final Context mContext;
+    private final NfcAdapter mNfcAdapter;
+    private final Preference mPreference;
+    private int mAirplaneMode;
+
+    @VisibleForTesting
+    final static Uri AIRPLANE_MODE_URI =
+            Settings.Global.getUriFor(Settings.Global.AIRPLANE_MODE_ON);
+
+    public NfcAirplaneModeObserver(Context context, NfcAdapter nfcAdapter, Preference preference) {
+        super(new Handler(Looper.getMainLooper()));
+        mContext = context;
+        mNfcAdapter = nfcAdapter;
+        mPreference = preference;
+        updateNfcPreference();
+    }
+
+    public void register() {
+        mContext.getContentResolver().registerContentObserver(AIRPLANE_MODE_URI, false, this);
+    }
+
+    public void unregister() {
+        mContext.getContentResolver().unregisterContentObserver(this);
+    }
+
+    @Override
+    public void onChange(boolean selfChange, Uri uri) {
+        super.onChange(selfChange, uri);
+        updateNfcPreference();
+    }
+
+    private void updateNfcPreference() {
+        final int airplaneMode = Settings.Global.getInt(
+                mContext.getContentResolver(), Settings.Global.AIRPLANE_MODE_ON, mAirplaneMode);
+        if (airplaneMode == mAirplaneMode) {
+            return;
+        }
+
+        mAirplaneMode = airplaneMode;
+        boolean toggleable = mAirplaneMode != 1;
+        if (toggleable) {
+            mNfcAdapter.enable();
+        } else {
+            mNfcAdapter.disable();
+        }
+        mPreference.setEnabled(toggleable);
+    }
+}