Merge "Fix bluetooth settings pairing page stuck" into udc-qpr-dev

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

@@ -128,7 +128,7 @@ public abstract class BluetoothDevicePairingDetailBase extends DeviceListPrefere
             if (device != null && mSelectedList.contains(device)) {
                 setResult(RESULT_OK);
                 finish();
-            } else if (mDevicePreferenceMap.containsKey(cachedDevice)) {
+            } else {
                 onDeviceDeleted(cachedDevice);
             }
         }
@@ -175,8 +175,6 @@ public abstract class BluetoothDevicePairingDetailBase extends DeviceListPrefere
     public void updateContent(int bluetoothState) {
         switch (bluetoothState) {
             case BluetoothAdapter.STATE_ON:
-                mDevicePreferenceMap.clear();
-                clearPreferenceGroupCache();
                 mBluetoothAdapter.enable();
                 enableScanning();
                 break;
@@ -187,14 +185,6 @@ public abstract class BluetoothDevicePairingDetailBase extends DeviceListPrefere
         }
     }
 
-    /**
-     * Clears all cached preferences in {@code preferenceGroup}.
-     */
-    private void clearPreferenceGroupCache() {
-        cacheRemoveAllPrefs(mAvailableDevicesCategory);
-        removeCachedPrefs(mAvailableDevicesCategory);
-    }
-
     @VisibleForTesting
     void showBluetoothTurnedOnToast() {
         Toast.makeText(getContext(), R.string.connected_device_bluetooth_turned_on_toast,

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008 The Android Open Source Project
+ * Copyright (C) 2023 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.
@@ -35,6 +35,8 @@ import android.view.View;
 import android.widget.ImageView;
 
 import androidx.annotation.IntDef;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
 import androidx.appcompat.app.AlertDialog;
 import androidx.preference.Preference;
@@ -52,6 +54,7 @@ import java.lang.annotation.RetentionPolicy;
 import java.util.HashSet;
 import java.util.Set;
 import java.util.concurrent.RejectedExecutionException;
+import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * BluetoothDevicePreference is the preference type used to display each remote
@@ -79,7 +82,9 @@ public final class BluetoothDevicePreference extends GearPreference {
     @VisibleForTesting
     BluetoothAdapter mBluetoothAdapter;
     private final boolean mShowDevicesWithoutNames;
-    private final long mCurrentTime;
+    @NonNull
+    private static final AtomicInteger sNextId = new AtomicInteger();
+    private final int mId;
     private final int mType;
 
     private AlertDialog mDisconnectDialog;
@@ -127,8 +132,9 @@ public final class BluetoothDevicePreference extends GearPreference {
 
         mCachedDevice = cachedDevice;
         mCallback = new BluetoothDevicePreferenceCallback();
-        mCurrentTime = System.currentTimeMillis();
+        mId = sNextId.getAndIncrement();
         mType = type;
+        setVisible(false);
 
         onPreferenceAttributesChanged();
     }
@@ -229,35 +235,41 @@ public final class BluetoothDevicePreference extends GearPreference {
 
     @SuppressWarnings("FutureReturnValueIgnored")
     void onPreferenceAttributesChanged() {
-        Pair<Drawable, String> pair = mCachedDevice.getDrawableWithDescription();
-        setIcon(pair.first);
-        contentDescription = pair.second;
-
-        /*
-         * The preference framework takes care of making sure the value has
-         * changed before proceeding. It will also call notifyChanged() if
-         * any preference info has changed from the previous value.
-         */
-        setTitle(mCachedDevice.getName());
         try {
             ThreadUtils.postOnBackgroundThread(() -> {
+                @Nullable String name = mCachedDevice.getName();
                 // Null check is done at the framework
-                ThreadUtils.postOnMainThread(() -> setSummary(getConnectionSummary()));
+                @Nullable String connectionSummary = getConnectionSummary();
+                @NonNull Pair<Drawable, String> pair = mCachedDevice.getDrawableWithDescription();
+                boolean isBusy = mCachedDevice.isBusy();
+                // Device is only visible in the UI if it has a valid name besides MAC address or
+                // when user allows showing devices without user-friendly name in developer settings
+                boolean isVisible =
+                        mShowDevicesWithoutNames || mCachedDevice.hasHumanReadableName();
+
+                ThreadUtils.postOnMainThread(() -> {
+                    /*
+                     * The preference framework takes care of making sure the value has
+                     * changed before proceeding. It will also call notifyChanged() if
+                     * any preference info has changed from the previous value.
+                     */
+                    setTitle(name);
+                    setSummary(connectionSummary);
+                    setIcon(pair.first);
+                    contentDescription = pair.second;
+                    // Used to gray out the item
+                    setEnabled(!isBusy);
+                    setVisible(isVisible);
+
+                    // This could affect ordering, so notify that
+                    if (mNeedNotifyHierarchyChanged) {
+                        notifyHierarchyChanged();
+                    }
+                });
             });
         } catch (RejectedExecutionException e) {
             Log.w(TAG, "Handler thread unavailable, skipping getConnectionSummary!");
         }
-        // Used to gray out the item
-        setEnabled(!mCachedDevice.isBusy());
-
-        // Device is only visible in the UI if it has a valid name besides MAC address or when user
-        // allows showing devices without user-friendly name in developer settings
-        setVisible(mShowDevicesWithoutNames || mCachedDevice.hasHumanReadableName());
-
-        // This could affect ordering, so notify that
-        if (mNeedNotifyHierarchyChanged) {
-            notifyHierarchyChanged();
-        }
     }
 
     @Override
@@ -311,7 +323,7 @@ public final class BluetoothDevicePreference extends GearPreference {
                 return mCachedDevice
                         .compareTo(((BluetoothDevicePreference) another).mCachedDevice);
             case SortType.TYPE_FIFO:
-                return mCurrentTime > ((BluetoothDevicePreference) another).mCurrentTime ? 1 : -1;
+                return mId > ((BluetoothDevicePreference) another).mId ? 1 : -1;
             default:
                 return super.compareTo(another);
         }

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

@@ -1,351 +0,0 @@
-/*
- * Copyright (C) 2011 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.BluetoothAdapter;
-import android.bluetooth.BluetoothDevice;
-import android.bluetooth.le.BluetoothLeScanner;
-import android.bluetooth.le.ScanCallback;
-import android.bluetooth.le.ScanFilter;
-import android.bluetooth.le.ScanResult;
-import android.bluetooth.le.ScanSettings;
-import android.os.Bundle;
-import android.os.SystemProperties;
-import android.text.BidiFormatter;
-import android.util.Log;
-
-import androidx.annotation.VisibleForTesting;
-import androidx.preference.Preference;
-import androidx.preference.PreferenceCategory;
-import androidx.preference.PreferenceGroup;
-
-import com.android.settings.R;
-import com.android.settings.dashboard.RestrictedDashboardFragment;
-import com.android.settingslib.bluetooth.BluetoothCallback;
-import com.android.settingslib.bluetooth.BluetoothDeviceFilter;
-import com.android.settingslib.bluetooth.CachedBluetoothDevice;
-import com.android.settingslib.bluetooth.CachedBluetoothDeviceManager;
-import com.android.settingslib.bluetooth.LocalBluetoothManager;
-
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.List;
-
-/**
- * Parent class for settings fragments that contain a list of Bluetooth
- * devices.
- *
- * @see DevicePickerFragment
- */
-// TODO: Refactor this fragment
-public abstract class DeviceListPreferenceFragment extends
-        RestrictedDashboardFragment implements BluetoothCallback {
-
-    private static final String TAG = "DeviceListPreferenceFragment";
-
-    private static final String KEY_BT_SCAN = "bt_scan";
-
-    // Copied from BluetoothDeviceNoNamePreferenceController.java
-    private static final String BLUETOOTH_SHOW_DEVICES_WITHOUT_NAMES_PROPERTY =
-            "persist.bluetooth.showdeviceswithoutnames";
-
-    private BluetoothDeviceFilter.Filter mFilter;
-    private List<ScanFilter> mLeScanFilters;
-    private ScanCallback mScanCallback;
-
-    @VisibleForTesting
-    protected boolean mScanEnabled;
-
-    protected BluetoothDevice mSelectedDevice;
-
-    protected BluetoothAdapter mBluetoothAdapter;
-    protected LocalBluetoothManager mLocalManager;
-    protected CachedBluetoothDeviceManager mCachedDeviceManager;
-
-    @VisibleForTesting
-    protected PreferenceGroup mDeviceListGroup;
-
-    protected final HashMap<CachedBluetoothDevice, BluetoothDevicePreference> mDevicePreferenceMap =
-            new HashMap<>();
-    protected final List<BluetoothDevice> mSelectedList = new ArrayList<>();
-
-    protected boolean mShowDevicesWithoutNames;
-
-    public DeviceListPreferenceFragment(String restrictedKey) {
-        super(restrictedKey);
-        mFilter = BluetoothDeviceFilter.ALL_FILTER;
-    }
-
-    protected final void setFilter(BluetoothDeviceFilter.Filter filter) {
-        mFilter = filter;
-    }
-
-    protected final void setFilter(int filterType) {
-        mFilter = BluetoothDeviceFilter.getFilter(filterType);
-    }
-
-    /**
-     * Sets the bluetooth device scanning filter with {@link ScanFilter}s. It will change to start
-     * {@link BluetoothLeScanner} which will scan BLE device only.
-     *
-     * @param leScanFilters list of settings to filter scan result
-     */
-    protected void setFilter(List<ScanFilter> leScanFilters) {
-        mFilter = null;
-        mLeScanFilters = leScanFilters;
-    }
-
-    @Override
-    public void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-
-        mLocalManager = Utils.getLocalBtManager(getActivity());
-        if (mLocalManager == null) {
-            Log.e(TAG, "Bluetooth is not supported on this device");
-            return;
-        }
-        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
-        mCachedDeviceManager = mLocalManager.getCachedDeviceManager();
-        mShowDevicesWithoutNames = SystemProperties.getBoolean(
-                BLUETOOTH_SHOW_DEVICES_WITHOUT_NAMES_PROPERTY, false);
-
-        initPreferencesFromPreferenceScreen();
-
-        mDeviceListGroup = (PreferenceCategory) findPreference(getDeviceListKey());
-    }
-
-    /** find and update preference that already existed in preference screen */
-    protected abstract void initPreferencesFromPreferenceScreen();
-
-    @Override
-    public void onStart() {
-        super.onStart();
-        if (mLocalManager == null || isUiRestricted()) return;
-
-        mLocalManager.setForegroundActivity(getActivity());
-        mLocalManager.getEventManager().registerCallback(this);
-    }
-
-    @Override
-    public void onStop() {
-        super.onStop();
-        if (mLocalManager == null || isUiRestricted()) {
-            return;
-        }
-
-        removeAllDevices();
-        mLocalManager.setForegroundActivity(null);
-        mLocalManager.getEventManager().unregisterCallback(this);
-    }
-
-    void removeAllDevices() {
-        mDevicePreferenceMap.clear();
-        mDeviceListGroup.removeAll();
-    }
-
-    void addCachedDevices() {
-        Collection<CachedBluetoothDevice> cachedDevices =
-                mCachedDeviceManager.getCachedDevicesCopy();
-        for (CachedBluetoothDevice cachedDevice : cachedDevices) {
-            onDeviceAdded(cachedDevice);
-        }
-    }
-
-    @Override
-    public boolean onPreferenceTreeClick(Preference preference) {
-        if (KEY_BT_SCAN.equals(preference.getKey())) {
-            startScanning();
-            return true;
-        }
-
-        if (preference instanceof BluetoothDevicePreference) {
-            BluetoothDevicePreference btPreference = (BluetoothDevicePreference) preference;
-            CachedBluetoothDevice device = btPreference.getCachedDevice();
-            mSelectedDevice = device.getDevice();
-            mSelectedList.add(mSelectedDevice);
-            onDevicePreferenceClick(btPreference);
-            return true;
-        }
-
-        return super.onPreferenceTreeClick(preference);
-    }
-
-    protected void onDevicePreferenceClick(BluetoothDevicePreference btPreference) {
-        btPreference.onClicked();
-    }
-
-    @Override
-    public void onDeviceAdded(CachedBluetoothDevice cachedDevice) {
-        if (mDevicePreferenceMap.get(cachedDevice) != null) {
-            return;
-        }
-
-        // Prevent updates while the list shows one of the state messages
-        if (mBluetoothAdapter.getState() != BluetoothAdapter.STATE_ON) {
-            return;
-        }
-
-        if (mFilter != null && mFilter.matches(cachedDevice.getDevice())) {
-            createDevicePreference(cachedDevice);
-        }
-    }
-
-    void createDevicePreference(CachedBluetoothDevice cachedDevice) {
-        if (mDeviceListGroup == null) {
-            Log.w(TAG, "Trying to create a device preference before the list group/category "
-                    + "exists!");
-            return;
-        }
-
-        String key = cachedDevice.getDevice().getAddress();
-        BluetoothDevicePreference preference = (BluetoothDevicePreference) getCachedPreference(key);
-
-        if (preference == null) {
-            preference = new BluetoothDevicePreference(getPrefContext(), cachedDevice,
-                    mShowDevicesWithoutNames, BluetoothDevicePreference.SortType.TYPE_FIFO);
-            preference.setKey(key);
-            //Set hideSecondTarget is true if it's bonded device.
-            preference.hideSecondTarget(true);
-            mDeviceListGroup.addPreference(preference);
-        }
-
-        initDevicePreference(preference);
-        mDevicePreferenceMap.put(cachedDevice, preference);
-    }
-
-    protected void initDevicePreference(BluetoothDevicePreference preference) {
-        // Does nothing by default
-    }
-
-    @VisibleForTesting
-    void updateFooterPreference(Preference myDevicePreference) {
-        final BidiFormatter bidiFormatter = BidiFormatter.getInstance();
-
-        myDevicePreference.setTitle(getString(
-                R.string.bluetooth_footer_mac_message,
-                bidiFormatter.unicodeWrap(mBluetoothAdapter.getAddress())));
-    }
-
-    @Override
-    public void onDeviceDeleted(CachedBluetoothDevice cachedDevice) {
-        BluetoothDevicePreference preference = mDevicePreferenceMap.remove(cachedDevice);
-        if (preference != null) {
-            mDeviceListGroup.removePreference(preference);
-        }
-    }
-
-    @VisibleForTesting
-    protected void enableScanning() {
-        // BluetoothAdapter already handles repeated scan requests
-        if (!mScanEnabled) {
-            startScanning();
-            mScanEnabled = true;
-        }
-    }
-
-    @VisibleForTesting
-    protected void disableScanning() {
-        if (mScanEnabled) {
-            stopScanning();
-            mScanEnabled = false;
-        }
-    }
-
-    @Override
-    public void onScanningStateChanged(boolean started) {
-        if (!started && mScanEnabled) {
-            startScanning();
-        }
-    }
-
-    /**
-     * Return the key of the {@link PreferenceGroup} that contains the bluetooth devices
-     */
-    public abstract String getDeviceListKey();
-
-    public boolean shouldShowDevicesWithoutNames() {
-        return mShowDevicesWithoutNames;
-    }
-
-    @VisibleForTesting
-    void startScanning() {
-        if (mFilter != null) {
-            startClassicScanning();
-        } else if (mLeScanFilters != null) {
-            startLeScanning();
-        }
-
-    }
-
-    @VisibleForTesting
-    void stopScanning() {
-        if (mFilter != null) {
-            stopClassicScanning();
-        } else if (mLeScanFilters != null) {
-            stopLeScanning();
-        }
-    }
-
-    private void startClassicScanning() {
-        if (!mBluetoothAdapter.isDiscovering()) {
-            mBluetoothAdapter.startDiscovery();
-        }
-    }
-
-    private void stopClassicScanning() {
-        if (mBluetoothAdapter.isDiscovering()) {
-            mBluetoothAdapter.cancelDiscovery();
-        }
-    }
-
-    private void startLeScanning() {
-        final BluetoothLeScanner scanner = mBluetoothAdapter.getBluetoothLeScanner();
-        final ScanSettings settings = new ScanSettings.Builder()
-                .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
-                .build();
-        mScanCallback = new ScanCallback() {
-            @Override
-            public void onScanResult(int callbackType, ScanResult result) {
-                final BluetoothDevice device = result.getDevice();
-                CachedBluetoothDevice cachedDevice = mCachedDeviceManager.findDevice(device);
-                if (cachedDevice == null) {
-                    cachedDevice = mCachedDeviceManager.addDevice(device);
-                }
-                // Only add device preference when it's not found in the map and there's no other
-                // state message showing in the list
-                if (mDevicePreferenceMap.get(cachedDevice) == null
-                        && mBluetoothAdapter.getState() == BluetoothAdapter.STATE_ON) {
-                    createDevicePreference(cachedDevice);
-                }
-            }
-
-            @Override
-            public void onScanFailed(int errorCode) {
-                Log.w(TAG, "BLE Scan failed with error code " + errorCode);
-            }
-        };
-        scanner.startScan(mLeScanFilters, settings, mScanCallback);
-    }
-
-    private void stopLeScanning() {
-        final BluetoothLeScanner scanner = mBluetoothAdapter.getBluetoothLeScanner();
-        if (scanner != null) {
-            scanner.stopScan(mScanCallback);
-        }
-    }
-}

src/com/android/settings/bluetooth/DeviceListPreferenceFragment.kt

@@ -0,0 +1,348 @@
+/*
+ * Copyright (C) 2023 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.BluetoothAdapter
+import android.bluetooth.BluetoothDevice
+import android.bluetooth.le.BluetoothLeScanner
+import android.bluetooth.le.ScanCallback
+import android.bluetooth.le.ScanFilter
+import android.bluetooth.le.ScanResult
+import android.bluetooth.le.ScanSettings
+import android.os.Bundle
+import android.os.SystemProperties
+import android.text.BidiFormatter
+import android.util.Log
+import android.view.View
+import androidx.annotation.VisibleForTesting
+import androidx.lifecycle.LifecycleCoroutineScope
+import androidx.lifecycle.lifecycleScope
+import androidx.preference.Preference
+import androidx.preference.PreferenceCategory
+import androidx.preference.PreferenceGroup
+import com.android.settings.R
+import com.android.settings.dashboard.RestrictedDashboardFragment
+import com.android.settingslib.bluetooth.BluetoothCallback
+import com.android.settingslib.bluetooth.BluetoothDeviceFilter
+import com.android.settingslib.bluetooth.CachedBluetoothDevice
+import com.android.settingslib.bluetooth.CachedBluetoothDeviceManager
+import com.android.settingslib.bluetooth.LocalBluetoothManager
+import java.util.concurrent.ConcurrentHashMap
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+
+/**
+ * Parent class for settings fragments that contain a list of Bluetooth devices.
+ *
+ * @see DevicePickerFragment
+ *
+ * TODO: Refactor this fragment
+ */
+abstract class DeviceListPreferenceFragment(restrictedKey: String?) :
+    RestrictedDashboardFragment(restrictedKey), BluetoothCallback {
+
+    private var filter: BluetoothDeviceFilter.Filter? = BluetoothDeviceFilter.ALL_FILTER
+    private var leScanFilters: List<ScanFilter>? = null
+
+    @JvmField
+    @VisibleForTesting
+    var mScanEnabled = false
+
+    @JvmField
+    var mSelectedDevice: BluetoothDevice? = null
+
+    @JvmField
+    var mBluetoothAdapter: BluetoothAdapter? = null
+
+    @JvmField
+    var mLocalManager: LocalBluetoothManager? = null
+
+    @JvmField
+    var mCachedDeviceManager: CachedBluetoothDeviceManager? = null
+
+    @JvmField
+    @VisibleForTesting
+    var mDeviceListGroup: PreferenceGroup? = null
+
+    @VisibleForTesting
+    val devicePreferenceMap =
+        ConcurrentHashMap<CachedBluetoothDevice, BluetoothDevicePreference>()
+
+    @JvmField
+    val mSelectedList: MutableList<BluetoothDevice> = ArrayList()
+
+    private var showDevicesWithoutNames = false
+
+    protected fun setFilter(filter: BluetoothDeviceFilter.Filter?) {
+        this.filter = filter
+    }
+
+    protected fun setFilter(filterType: Int) {
+        filter = BluetoothDeviceFilter.getFilter(filterType)
+    }
+
+    /**
+     * Sets the bluetooth device scanning filter with [ScanFilter]s. It will change to start
+     * [BluetoothLeScanner] which will scan BLE device only.
+     *
+     * @param leScanFilters list of settings to filter scan result
+     */
+    fun setFilter(leScanFilters: List<ScanFilter>?) {
+        filter = null
+        this.leScanFilters = leScanFilters
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        mLocalManager = Utils.getLocalBtManager(activity)
+        if (mLocalManager == null) {
+            Log.e(TAG, "Bluetooth is not supported on this device")
+            return
+        }
+        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter()
+        mCachedDeviceManager = mLocalManager!!.cachedDeviceManager
+        showDevicesWithoutNames = SystemProperties.getBoolean(
+            BLUETOOTH_SHOW_DEVICES_WITHOUT_NAMES_PROPERTY, false
+        )
+        initPreferencesFromPreferenceScreen()
+        mDeviceListGroup = findPreference<Preference>(deviceListKey) as PreferenceCategory
+    }
+
+    /** find and update preference that already existed in preference screen  */
+    protected abstract fun initPreferencesFromPreferenceScreen()
+
+    private var lifecycleScope: LifecycleCoroutineScope? = null
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+        lifecycleScope = viewLifecycleOwner.lifecycleScope
+    }
+
+    override fun onStart() {
+        super.onStart()
+        if (mLocalManager == null || isUiRestricted) return
+        mLocalManager!!.foregroundActivity = activity
+        mLocalManager!!.eventManager.registerCallback(this)
+    }
+
+    override fun onStop() {
+        super.onStop()
+        if (mLocalManager == null || isUiRestricted) {
+            return
+        }
+        removeAllDevices()
+        mLocalManager!!.foregroundActivity = null
+        mLocalManager!!.eventManager.unregisterCallback(this)
+    }
+
+    fun removeAllDevices() {
+        devicePreferenceMap.clear()
+        mDeviceListGroup!!.removeAll()
+    }
+
+    fun addCachedDevices() {
+        lifecycleScope?.launch {
+            withContext(Dispatchers.Default) {
+                val cachedDevices = mCachedDeviceManager!!.cachedDevicesCopy
+                for (cachedDevice in cachedDevices) {
+                    onDeviceAdded(cachedDevice)
+                }
+            }
+        }
+    }
+
+    override fun onPreferenceTreeClick(preference: Preference): Boolean {
+        if (KEY_BT_SCAN == preference.key) {
+            startScanning()
+            return true
+        }
+        if (preference is BluetoothDevicePreference) {
+            val device = preference.cachedDevice.device
+            mSelectedDevice = device
+            mSelectedList.add(device)
+            onDevicePreferenceClick(preference)
+            return true
+        }
+        return super.onPreferenceTreeClick(preference)
+    }
+
+    protected open fun onDevicePreferenceClick(btPreference: BluetoothDevicePreference) {
+        btPreference.onClicked()
+    }
+
+    override fun onDeviceAdded(cachedDevice: CachedBluetoothDevice) {
+        lifecycleScope?.launch {
+            addDevice(cachedDevice)
+        }
+    }
+
+    private suspend fun addDevice(cachedDevice: CachedBluetoothDevice) =
+        withContext(Dispatchers.Default) {
+            // Prevent updates while the list shows one of the state messages
+            if (mBluetoothAdapter!!.state == BluetoothAdapter.STATE_ON &&
+                filter?.matches(cachedDevice.device) == true
+            ) {
+                createDevicePreference(cachedDevice)
+            }
+        }
+
+    private suspend fun createDevicePreference(cachedDevice: CachedBluetoothDevice) {
+        if (mDeviceListGroup == null) {
+            Log.w(
+                TAG,
+                "Trying to create a device preference before the list group/category exists!",
+            )
+            return
+        }
+        // Only add device preference when it's not found in the map and there's no other state
+        // message showing in the list
+        val preference = devicePreferenceMap.computeIfAbsent(cachedDevice) {
+            BluetoothDevicePreference(
+                prefContext,
+                cachedDevice,
+                showDevicesWithoutNames,
+                BluetoothDevicePreference.SortType.TYPE_FIFO,
+            ).apply {
+                key = cachedDevice.device.address
+                //Set hideSecondTarget is true if it's bonded device.
+                hideSecondTarget(true)
+            }
+        }
+        withContext(Dispatchers.Main) {
+            mDeviceListGroup!!.addPreference(preference)
+            initDevicePreference(preference)
+        }
+    }
+
+    protected open fun initDevicePreference(preference: BluetoothDevicePreference?) {
+        // Does nothing by default
+    }
+
+    @VisibleForTesting
+    fun updateFooterPreference(myDevicePreference: Preference) {
+        val bidiFormatter = BidiFormatter.getInstance()
+        myDevicePreference.title = getString(
+            R.string.bluetooth_footer_mac_message,
+            bidiFormatter.unicodeWrap(mBluetoothAdapter!!.address)
+        )
+    }
+
+    override fun onDeviceDeleted(cachedDevice: CachedBluetoothDevice) {
+        devicePreferenceMap.remove(cachedDevice)?.let {
+            mDeviceListGroup!!.removePreference(it)
+        }
+    }
+
+    @VisibleForTesting
+    open fun enableScanning() {
+        // BluetoothAdapter already handles repeated scan requests
+        if (!mScanEnabled) {
+            startScanning()
+            mScanEnabled = true
+        }
+    }
+
+    @VisibleForTesting
+    fun disableScanning() {
+        if (mScanEnabled) {
+            stopScanning()
+            mScanEnabled = false
+        }
+    }
+
+    override fun onScanningStateChanged(started: Boolean) {
+        if (!started && mScanEnabled) {
+            startScanning()
+        }
+    }
+
+    /**
+     * Return the key of the [PreferenceGroup] that contains the bluetooth devices
+     */
+    abstract val deviceListKey: String
+
+    @VisibleForTesting
+    open fun startScanning() {
+        if (filter != null) {
+            startClassicScanning()
+        } else if (leScanFilters != null) {
+            startLeScanning()
+        }
+    }
+
+    @VisibleForTesting
+    open fun stopScanning() {
+        if (filter != null) {
+            stopClassicScanning()
+        } else if (leScanFilters != null) {
+            stopLeScanning()
+        }
+    }
+
+    private fun startClassicScanning() {
+        if (!mBluetoothAdapter!!.isDiscovering) {
+            mBluetoothAdapter!!.startDiscovery()
+        }
+    }
+
+    private fun stopClassicScanning() {
+        if (mBluetoothAdapter!!.isDiscovering) {
+            mBluetoothAdapter!!.cancelDiscovery()
+        }
+    }
+
+    private val scanCallback = object : ScanCallback() {
+        override fun onScanResult(callbackType: Int, result: ScanResult) {
+            lifecycleScope?.launch {
+                withContext(Dispatchers.Default) {
+                    if (mBluetoothAdapter!!.state == BluetoothAdapter.STATE_ON) {
+                        val device = result.device
+                        val cachedDevice = mCachedDeviceManager!!.findDevice(device)
+                            ?: mCachedDeviceManager!!.addDevice(device)
+                        createDevicePreference(cachedDevice)
+                    }
+                }
+            }
+        }
+
+        override fun onScanFailed(errorCode: Int) {
+            Log.w(TAG, "BLE Scan failed with error code $errorCode")
+        }
+    }
+
+    private fun startLeScanning() {
+        val scanner = mBluetoothAdapter!!.bluetoothLeScanner
+        val settings = ScanSettings.Builder()
+            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
+            .build()
+        scanner.startScan(leScanFilters, settings, scanCallback)
+    }
+
+    private fun stopLeScanning() {
+        val scanner = mBluetoothAdapter!!.bluetoothLeScanner
+        scanner?.stopScan(scanCallback)
+    }
+
+    companion object {
+        private const val TAG = "DeviceListPreferenceFragment"
+        private const val KEY_BT_SCAN = "bt_scan"
+
+        // Copied from BluetoothDeviceNoNamePreferenceController.java
+        private const val BLUETOOTH_SHOW_DEVICES_WITHOUT_NAMES_PROPERTY =
+            "persist.bluetooth.showdeviceswithoutnames"
+    }
+}

tests/robotests/src/com/android/settings/bluetooth/BluetoothDevicePairingDetailBaseTest.java

@@ -202,7 +202,7 @@ public class BluetoothDevicePairingDetailBaseTest {
                 new BluetoothDevicePreference(mContext, mCachedBluetoothDevice,
                         true, BluetoothDevicePreference.SortType.TYPE_FIFO);
         final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(TEST_DEVICE_ADDRESS);
-        mFragment.mDevicePreferenceMap.put(mCachedBluetoothDevice, preference);
+        mFragment.getDevicePreferenceMap().put(mCachedBluetoothDevice, preference);
 
         when(mCachedBluetoothDevice.isConnected()).thenReturn(true);
         when(mCachedBluetoothDevice.getDevice()).thenReturn(device);
@@ -210,7 +210,7 @@ public class BluetoothDevicePairingDetailBaseTest {
         mFragment.onProfileConnectionStateChanged(mCachedBluetoothDevice,
                 BluetoothProfile.A2DP, BluetoothAdapter.STATE_CONNECTED);
 
-        assertThat(mFragment.mDevicePreferenceMap.size()).isEqualTo(0);
+        assertThat(mFragment.getDevicePreferenceMap().size()).isEqualTo(0);
     }
 
     @Test
@@ -221,7 +221,7 @@ public class BluetoothDevicePairingDetailBaseTest {
                         true, BluetoothDevicePreference.SortType.TYPE_FIFO);
         final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(TEST_DEVICE_ADDRESS);
         final BluetoothDevice device2 = mBluetoothAdapter.getRemoteDevice(TEST_DEVICE_ADDRESS_B);
-        mFragment.mDevicePreferenceMap.put(mCachedBluetoothDevice, preference);
+        mFragment.getDevicePreferenceMap().put(mCachedBluetoothDevice, preference);
 
         when(mCachedBluetoothDevice.isConnected()).thenReturn(true);
         when(mCachedBluetoothDevice.getDevice()).thenReturn(device);

tests/robotests/src/com/android/settings/bluetooth/BluetoothPairingDetailTest.java

@@ -27,7 +27,12 @@ import static org.mockito.Mockito.verify;
 import android.bluetooth.BluetoothAdapter;
 import android.content.Context;
 import android.os.Bundle;
+import android.view.View;
 
+import androidx.annotation.NonNull;
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.LifecycleObserver;
+import androidx.lifecycle.LifecycleOwner;
 import androidx.test.core.app.ApplicationProvider;
 
 import com.android.settingslib.bluetooth.CachedBluetoothDeviceManager;
@@ -53,6 +58,20 @@ public class BluetoothPairingDetailTest {
 
     private final Context mContext = ApplicationProvider.getApplicationContext();
 
+    private final Lifecycle mFakeLifecycle = new Lifecycle() {
+        @Override
+        public void addObserver(@NonNull LifecycleObserver observer) {}
+
+        @Override
+        public void removeObserver(@NonNull LifecycleObserver observer) {}
+
+        @NonNull
+        @Override
+        public State getCurrentState() {
+            return State.CREATED;
+        }
+    };
+
     @Mock(answer = Answers.RETURNS_DEEP_STUBS)
     private LocalBluetoothManager mLocalManager;
     @Mock(answer = Answers.RETURNS_DEEP_STUBS)
@@ -74,6 +93,8 @@ public class BluetoothPairingDetailTest {
                 .findPreference(BluetoothPairingDetail.KEY_AVAIL_DEVICES);
         doReturn(mFooterPreference).when(mFragment)
                 .findPreference(BluetoothPairingDetail.KEY_FOOTER_PREF);
+        doReturn(new View(mContext)).when(mFragment).getView();
+        doReturn((LifecycleOwner) () -> mFakeLifecycle).when(mFragment).getViewLifecycleOwner();
         doReturn(Collections.emptyList()).when(mDeviceManager).getCachedDevicesCopy();
 
         mFragment.mBluetoothAdapter = mBluetoothAdapter;
@@ -82,7 +103,7 @@ public class BluetoothPairingDetailTest {
         mFragment.mDeviceListGroup = mAvailableDevicesCategory;
         mFragment.onViewCreated(mFragment.getView(), Bundle.EMPTY);
     }
-//
+
     @Test
     public void initPreferencesFromPreferenceScreen_findPreferences() {
         mFragment.initPreferencesFromPreferenceScreen();