Add a Preference into "Network & internet" for new tethering UI

Adding a MasterSwitchPreference into "Network & internet" and create
corresponding controller. The preference is hidden by the feature flag.
It does NOT affect the existing UI.

Bug: 146147778
Test: CodeInspectionTest, TetherPreferenceControllerTest,
NetworkDashboardFragmentTest
Change-Id: Ida8e088efbb22d0c983acecbc420672206392dad

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

@@ -0,0 +1,151 @@
+/*
+ * 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;
+
+import static android.os.UserManager.DISALLOW_CONFIG_TETHERING;
+
+import static com.android.settingslib.RestrictedLockUtilsInternal.checkIfRestrictionEnforced;
+
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothPan;
+import android.bluetooth.BluetoothProfile;
+import android.content.Context;
+import android.os.UserHandle;
+import android.util.FeatureFlagUtils;
+import android.util.Log;
+
+import androidx.annotation.VisibleForTesting;
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.Lifecycle.Event;
+import androidx.lifecycle.LifecycleObserver;
+import androidx.lifecycle.OnLifecycleEvent;
+import androidx.preference.PreferenceScreen;
+
+import com.android.settings.TetherSettings;
+import com.android.settings.core.BasePreferenceController;
+import com.android.settings.core.FeatureFlags;
+import com.android.settings.widget.MasterSwitchController;
+import com.android.settings.widget.MasterSwitchPreference;
+import com.android.settingslib.TetherUtil;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * This controller helps to manage the switch state and visibility of "Hotspot & tethering" switch
+ * preference. It updates the preference summary text based on tethering state.
+ */
+public class AllInOneTetherPreferenceController extends BasePreferenceController implements
+        LifecycleObserver {
+    private static final String TAG = "AllInOneTetherPreferenceController";
+
+    private final boolean mAdminDisallowedTetherConfig;
+    private final AtomicReference<BluetoothPan> mBluetoothPan;
+    private final BluetoothAdapter mBluetoothAdapter;
+    @VisibleForTesting
+    final BluetoothProfile.ServiceListener mBtProfileServiceListener =
+            new BluetoothProfile.ServiceListener() {
+                @Override
+                public void onServiceConnected(int profile, BluetoothProfile proxy) {
+                    mBluetoothPan.set((BluetoothPan) proxy);
+                }
+
+                @Override
+                public void onServiceDisconnected(int profile) {
+                    mBluetoothPan.set(null);
+                }
+            };
+
+    private MasterSwitchPreference mPreference;
+
+    @VisibleForTesting(otherwise = VisibleForTesting.NONE)
+    AllInOneTetherPreferenceController() {
+        super(null /*context*/, "test");
+        mAdminDisallowedTetherConfig = false;
+        mBluetoothPan = new AtomicReference<>();
+        mBluetoothAdapter = null;
+    }
+
+    public AllInOneTetherPreferenceController(Context context, String key) {
+        super(context, key);
+        mBluetoothPan = new AtomicReference<>();
+        mAdminDisallowedTetherConfig = checkIfRestrictionEnforced(
+                context, DISALLOW_CONFIG_TETHERING, UserHandle.myUserId()) != null;
+        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+        mPreference = screen.findPreference(mPreferenceKey);
+        if (mPreference != null && !mAdminDisallowedTetherConfig) {
+            // Grey out if provisioning is not available.
+            mPreference.setEnabled(!TetherSettings.isProvisioningNeededButUnavailable(mContext));
+        }
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        if (!TetherUtil.isTetherAvailable(mContext)
+                || !FeatureFlagUtils.isEnabled(mContext, FeatureFlags.TETHER_ALL_IN_ONE)) {
+            return CONDITIONALLY_UNAVAILABLE;
+        } else {
+            return AVAILABLE;
+        }
+    }
+
+    @Override
+    public CharSequence getSummary() {
+        if (mPreference != null && mPreference.isChecked()) {
+            // TODO(b/149256198) update summary accordingly.
+            return "Tethering";
+        }
+
+        return "Not sharing internet with other devices";
+    }
+
+    @OnLifecycleEvent(Event.ON_CREATE)
+    public void onCreate() {
+        if (mBluetoothAdapter != null
+                && mBluetoothAdapter.getState() == BluetoothAdapter.STATE_ON) {
+            mBluetoothAdapter.getProfileProxy(mContext, mBtProfileServiceListener,
+                        BluetoothProfile.PAN);
+        }
+    }
+
+    @OnLifecycleEvent(Event.ON_DESTROY)
+    public void onDestroy() {
+        final BluetoothProfile profile = mBluetoothPan.getAndSet(null);
+        if (profile != null && mBluetoothAdapter != null) {
+            mBluetoothAdapter.closeProfileProxy(BluetoothProfile.PAN, profile);
+        }
+    }
+
+    void init(Lifecycle lifecycle) {
+        lifecycle.addObserver(this);
+    }
+
+    void initEnabler(Lifecycle lifecycle) {
+        if (mPreference != null) {
+            TetherEnabler tetherEnabler = new TetherEnabler(
+                    mContext, new MasterSwitchController(mPreference), mBluetoothPan);
+            if (lifecycle != null) {
+                lifecycle.addObserver(tetherEnabler);
+            }
+        } else {
+            Log.e(TAG, "TetherEnabler is not initialized");
+        }
+    }
+}