Add infrastructure for connected device group.

The core thing is to find out a way to update group when devices
(bt device and usb device)are updated.

The infrastructure contains three parts:
1. ConnectedDeviceController
Normal PreferenceController. Get info from sub controller and update
the preferenceGroup.

2. BluetoothDeviceUpdater
Listen to bluetooth callback, decide whether to add/remove devices

3. DevicePreferenceCallback
Interface to add/remove preference. This interface will be used in
ConntectedDeviceController and future SavedDeviceController

Bug: 69333961
Test: RunsettingsRoboTests
Change-Id: I85a9ef216a801d5f0dd1cf0130d53850a68be4bd

src/com/android/settings/bluetooth/BluetoothDeviceUpdater.java

@@ -0,0 +1,181 @@
+/*
+ * Copyright (C) 2017 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.bluetooth;
+
+import android.bluetooth.BluetoothDevice;
+import android.content.Context;
+import android.os.Bundle;
+import android.os.SystemProperties;
+import android.support.annotation.VisibleForTesting;
+import android.support.v7.preference.Preference;
+
+import com.android.settings.R;
+import com.android.settings.SettingsActivity;
+import com.android.settings.dashboard.DashboardFragment;
+import com.android.settings.connecteddevice.DevicePreferenceCallback;
+import com.android.settings.widget.GearPreference;
+import com.android.settingslib.bluetooth.BluetoothCallback;
+import com.android.settingslib.bluetooth.BluetoothDeviceFilter;
+import com.android.settingslib.bluetooth.CachedBluetoothDevice;
+import com.android.settingslib.bluetooth.LocalBluetoothManager;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Update the bluetooth devices. It gets bluetooth event from {@link LocalBluetoothManager} using
+ * {@link BluetoothCallback}. It notifies the upper level whether to add/remove the preference
+ * through {@link DevicePreferenceCallback}
+ *
+ * In {@link BluetoothDeviceUpdater}, it uses {@link BluetoothDeviceFilter.Filter} to detect
+ * whether the {@link CachedBluetoothDevice} is relevant.
+ */
+public abstract class BluetoothDeviceUpdater implements BluetoothCallback {
+    private static final String BLUETOOTH_SHOW_DEVICES_WITHOUT_NAMES_PROPERTY =
+            "persist.bluetooth.showdeviceswithoutnames";
+
+    protected final LocalBluetoothManager mLocalManager;
+    protected final DevicePreferenceCallback mDevicePreferenceCallback;
+    protected final Map<BluetoothDevice, Preference> mPreferenceMap;
+    protected Context mPrefContext;
+
+    private final boolean mShowDeviceWithoutNames;
+    private DashboardFragment mFragment;
+
+    @VisibleForTesting
+    final GearPreference.OnGearClickListener mDeviceProfilesListener = pref -> {
+        final CachedBluetoothDevice device =
+                ((BluetoothDevicePreference) pref).getBluetoothDevice();
+        if (device == null) {
+            return;
+        }
+        final Bundle args = new Bundle();
+        args.putString(BluetoothDeviceDetailsFragment.KEY_DEVICE_ADDRESS,
+                device.getDevice().getAddress());
+        final SettingsActivity activity = (SettingsActivity) mFragment.getActivity();
+        activity.startPreferencePanel(mFragment,
+                BluetoothDeviceDetailsFragment.class.getName(), args,
+                R.string.device_details_title, null, null, 0);
+
+    };
+
+    public BluetoothDeviceUpdater(DashboardFragment fragment,
+            DevicePreferenceCallback devicePreferenceCallback) {
+        this(fragment, devicePreferenceCallback, Utils.getLocalBtManager(fragment.getContext()));
+    }
+
+    @VisibleForTesting
+    BluetoothDeviceUpdater(DashboardFragment fragment,
+            DevicePreferenceCallback devicePreferenceCallback, LocalBluetoothManager localManager) {
+        mFragment = fragment;
+        mDevicePreferenceCallback = devicePreferenceCallback;
+        mShowDeviceWithoutNames = SystemProperties.getBoolean(
+                BLUETOOTH_SHOW_DEVICES_WITHOUT_NAMES_PROPERTY, false);
+        mPreferenceMap = new HashMap<>();
+        mLocalManager = localManager;
+    }
+
+    /**
+     * Register the bluetooth event callback and update the list
+     */
+    public void registerCallback() {
+        mLocalManager.setForegroundActivity(mFragment.getContext());
+        mLocalManager.getEventManager().registerCallback(this);
+        forceUpdate();
+    }
+
+    /**
+     * Unregister the bluetooth event callback
+     */
+    public void unregisterCallback() {
+        mLocalManager.setForegroundActivity(null);
+        mLocalManager.getEventManager().unregisterCallback(this);
+    }
+
+    /**
+     * Force to update the list of bluetooth devices
+     */
+    public void forceUpdate() {
+        Collection<CachedBluetoothDevice> cachedDevices =
+                mLocalManager.getCachedDeviceManager().getCachedDevicesCopy();
+        for (CachedBluetoothDevice cachedBluetoothDevice : cachedDevices) {
+            update(cachedBluetoothDevice);
+        }
+    }
+
+    @Override
+    public void onBluetoothStateChanged(int bluetoothState) {
+        forceUpdate();
+    }
+
+    @Override
+    public void onScanningStateChanged(boolean started) {}
+
+    @Override
+    public void onDeviceAdded(CachedBluetoothDevice cachedDevice) {
+        update(cachedDevice);
+    }
+
+    @Override
+    public void onDeviceDeleted(CachedBluetoothDevice cachedDevice) {}
+
+    @Override
+    public void onDeviceBondStateChanged(CachedBluetoothDevice cachedDevice, int bondState) {
+        update(cachedDevice);
+    }
+
+    @Override
+    public void onConnectionStateChanged(CachedBluetoothDevice cachedDevice, int state) {}
+
+    /**
+     * Set the context to generate the {@link Preference}, so it could get the correct theme.
+     */
+    public void setPrefContext(Context context) {
+        mPrefContext = context;
+    }
+
+    /**
+     * Update whether to show {@cde cachedBluetoothDevice} in the list.
+     */
+    abstract public void update(CachedBluetoothDevice cachedBluetoothDevice);
+
+    /**
+     * Add the {@link Preference} that represents the {@code cachedDevice}
+     */
+    protected void addPreference(CachedBluetoothDevice cachedDevice) {
+        final BluetoothDevice device = cachedDevice.getDevice();
+        if (!mPreferenceMap.containsKey(device)) {
+            BluetoothDevicePreference btPreference =
+                    new BluetoothDevicePreference(mPrefContext, cachedDevice,
+                            mShowDeviceWithoutNames);
+            btPreference.setOnGearClickListener(mDeviceProfilesListener);
+            mPreferenceMap.put(device, btPreference);
+            mDevicePreferenceCallback.onDeviceAdded(btPreference);
+        }
+    }
+
+    /**
+     * Remove the {@link Preference} that represents the {@code cachedDevice}
+     */
+    protected void removePreference(CachedBluetoothDevice cachedDevice) {
+        final BluetoothDevice device = cachedDevice.getDevice();
+        if (mPreferenceMap.containsKey(device)) {
+            mDevicePreferenceCallback.onDeviceRemoved(mPreferenceMap.get(device));
+            mPreferenceMap.remove(device);
+        }
+    }
+}