Merge "Add SystemUI component to watch for keyboard attachment." into mnc-dr-dev

6 files changed, 602 insertions, 0 deletions

diff --git a/packages/SettingsLib/src/com/android/settingslib/bluetooth/LocalBluetoothAdapter.java b/packages/SettingsLib/src/com/android/settingslib/bluetooth/LocalBluetoothAdapter.java
index 0380e21..f935f31 100644
--- a/packages/SettingsLib/src/com/android/settingslib/bluetooth/LocalBluetoothAdapter.java
+++ b/packages/SettingsLib/src/com/android/settingslib/bluetooth/LocalBluetoothAdapter.java
@@ -19,6 +19,7 @@ package com.android.settingslib.bluetooth;
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothDevice;
 import android.bluetooth.BluetoothProfile;
+import android.bluetooth.le.BluetoothLeScanner;
 import android.content.Context;
 import android.os.ParcelUuid;
 import android.util.Log;
@@ -106,6 +107,10 @@ public final class LocalBluetoothAdapter {
         return mAdapter.getScanMode();
     }
 
+    public BluetoothLeScanner getBluetoothLeScanner() {
+        return mAdapter.getBluetoothLeScanner();
+    }
+
     public int getState() {
         return mAdapter.getState();
     }
diff --git a/packages/SystemUI/AndroidManifest.xml b/packages/SystemUI/AndroidManifest.xml
index 372fa03..80f4d4c 100644
--- a/packages/SystemUI/AndroidManifest.xml
+++ b/packages/SystemUI/AndroidManifest.xml
@@ -127,6 +127,9 @@
     <!-- Assist -->
     <uses-permission android:name="android.permission.ACCESS_VOICE_INTERACTION_SERVICE" />
 
+    <!-- Listen for keyboard attachment / detachment -->
+    <uses-permission android:name="android.permission.TABLET_MODE" />
+
     <!-- Self permission for internal broadcasts. -->
     <permission android:name="com.android.systemui.permission.SELF"
             android:protectionLevel="signature" />
diff --git a/packages/SystemUI/res/values/strings.xml b/packages/SystemUI/res/values/strings.xml
index dfa85ce..dc9c9fd 100644
--- a/packages/SystemUI/res/values/strings.xml
+++ b/packages/SystemUI/res/values/strings.xml
@@ -1126,4 +1126,14 @@
     <!-- Dialog asking if the tuner should really be removed from settings [CHAR LIMIT=NONE]-->
     <string name="remove_from_settings_prompt">Remove System UI Tuner from Settings and stop using all of its features?"</string>
 
+    <!-- Dialog title asking if Bluetooth should be enabled [CHAR LIMIT=NONE] -->
+    <string name="enable_bluetooth_title">Turn on Bluetooth?</string>
+
+    <!-- Dialog message explaining why Bluetooth should be enabled when a packaged keyboard is
+         conncted to the device [CHAR LIMIT=NONE] -->
+    <string name="enable_bluetooth_message">To connect your keyboard with your tablet, you first have to turn on Bluetooth.</string>
+
+    <!-- Bluetooth enablement ok text [CHAR LIMIT=40] -->
+    <string name="enable_bluetooth_confirmation_ok">Turn on</string>
+
 </resources>
diff --git a/packages/SystemUI/src/com/android/systemui/SystemUIApplication.java b/packages/SystemUI/src/com/android/systemui/SystemUIApplication.java
index 33bd726..0b066af 100644
--- a/packages/SystemUI/src/com/android/systemui/SystemUIApplication.java
+++ b/packages/SystemUI/src/com/android/systemui/SystemUIApplication.java
@@ -48,6 +48,7 @@ public class SystemUIApplication extends Application {
             com.android.systemui.usb.StorageNotification.class,
             com.android.systemui.power.PowerUI.class,
             com.android.systemui.media.RingtonePlayer.class,
+            com.android.systemui.keyboard.KeyboardUI.class,
     };
 
     /**
diff --git a/packages/SystemUI/src/com/android/systemui/keyboard/BluetoothDialog.java b/packages/SystemUI/src/com/android/systemui/keyboard/BluetoothDialog.java
new file mode 100644
index 0000000..64f3e13
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/keyboard/BluetoothDialog.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2015 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.systemui.keyboard;
+
+import android.app.AlertDialog;
+import android.content.Context;
+import android.view.WindowManager;
+
+import com.android.systemui.R;
+import com.android.systemui.statusbar.phone.SystemUIDialog;
+
+public class BluetoothDialog extends SystemUIDialog {
+
+    public BluetoothDialog(Context context) {
+        super(context);
+
+        getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_DIALOG);
+        setShowForAllUsers(true);
+    }
+}
diff --git a/packages/SystemUI/src/com/android/systemui/keyboard/KeyboardUI.java b/packages/SystemUI/src/com/android/systemui/keyboard/KeyboardUI.java
new file mode 100644
index 0000000..a43d520
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/keyboard/KeyboardUI.java
@@ -0,0 +1,549 @@
+/*
+ * Copyright (C) 2015 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.systemui.keyboard;
+
+import android.app.AlertDialog;
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothDevice;
+import android.bluetooth.BluetoothManager;
+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.content.ContentResolver;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.content.res.Configuration;
+import android.hardware.input.InputManager;
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.os.Looper;
+import android.os.Message;
+import android.os.Process;
+import android.os.SystemClock;
+import android.os.UserHandle;
+import android.provider.Settings.Secure;
+import android.text.TextUtils;
+import android.util.Slog;
+import android.view.WindowManager;
+
+import com.android.settingslib.bluetooth.BluetoothCallback;
+import com.android.settingslib.bluetooth.CachedBluetoothDevice;
+import com.android.settingslib.bluetooth.CachedBluetoothDeviceManager;
+import com.android.settingslib.bluetooth.LocalBluetoothAdapter;
+import com.android.settingslib.bluetooth.LocalBluetoothManager;
+import com.android.settingslib.bluetooth.LocalBluetoothProfileManager;
+import com.android.systemui.R;
+import com.android.systemui.SystemUI;
+
+import java.io.FileDescriptor;
+import java.io.PrintWriter;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+public class KeyboardUI extends SystemUI implements InputManager.OnTabletModeChangedListener {
+    private static final String TAG = "KeyboardUI";
+    private static final boolean DEBUG = false;
+
+    // Give BT some time to start after SyUI comes up. This avoids flashing a dialog in the user's
+    // face because BT starts a little bit later in the boot process than SysUI and it takes some
+    // time for us to receive the signal that it's starting.
+    private static final long BLUETOOTH_START_DELAY_MILLIS = 10 * 1000;
+
+    private static final int STATE_NOT_ENABLED = -1;
+    private static final int STATE_UNKNOWN = 0;
+    private static final int STATE_WAITING_FOR_BOOT_COMPLETED = 1;
+    private static final int STATE_WAITING_FOR_TABLET_MODE_EXIT = 2;
+    private static final int STATE_WAITING_FOR_DEVICE_DISCOVERY = 3;
+    private static final int STATE_WAITING_FOR_BLUETOOTH = 4;
+    private static final int STATE_WAITING_FOR_STATE_PAIRED = 5;
+    private static final int STATE_PAIRING = 6;
+    private static final int STATE_PAIRED = 7;
+    private static final int STATE_USER_CANCELLED = 8;
+    private static final int STATE_DEVICE_NOT_FOUND = 9;
+
+    private static final int MSG_INIT = 0;
+    private static final int MSG_ON_BOOT_COMPLETED = 1;
+    private static final int MSG_PROCESS_KEYBOARD_STATE = 2;
+    private static final int MSG_ENABLE_BLUETOOTH = 3;
+    private static final int MSG_ON_BLUETOOTH_STATE_CHANGED = 4;
+    private static final int MSG_ON_DEVICE_BOND_STATE_CHANGED = 5;
+    private static final int MSG_ON_BLUETOOTH_DEVICE_ADDED = 6;
+    private static final int MSG_ON_BLE_SCAN_FAILED = 7;
+    private static final int MSG_SHOW_BLUETOOTH_DIALOG = 8;
+    private static final int MSG_DISMISS_BLUETOOTH_DIALOG = 9;
+
+    private volatile KeyboardHandler mHandler;
+    private volatile KeyboardUIHandler mUIHandler;
+
+    protected volatile Context mContext;
+
+    private boolean mEnabled;
+    private String mKeyboardName;
+    private CachedBluetoothDeviceManager mCachedDeviceManager;
+    private LocalBluetoothAdapter mLocalBluetoothAdapter;
+    private LocalBluetoothProfileManager mProfileManager;
+    private boolean mBootCompleted;
+    private long mBootCompletedTime;
+
+    private int mInTabletMode = InputManager.SWITCH_STATE_UNKNOWN;
+    private ScanCallback mScanCallback;
+    private BluetoothDialog mDialog;
+
+    private int mState;
+
+    @Override
+    public void start() {
+        mContext = super.mContext;
+        HandlerThread thread = new HandlerThread("Keyboard", Process.THREAD_PRIORITY_BACKGROUND);
+        thread.start();
+        mHandler = new KeyboardHandler(thread.getLooper());
+        mHandler.sendEmptyMessage(MSG_INIT);
+    }
+
+    @Override
+    protected void onConfigurationChanged(Configuration newConfig) {
+    }
+
+    @Override
+    public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
+        pw.println("KeyboardUI:");
+        pw.println("  mEnabled=" + mEnabled);
+        pw.println("  mBootCompleted=" + mEnabled);
+        pw.println("  mBootCompletedTime=" + mBootCompletedTime);
+        pw.println("  mKeyboardName=" + mKeyboardName);
+        pw.println("  mInTabletMode=" + mInTabletMode);
+        pw.println("  mState=" + stateToString(mState));
+    }
+
+    @Override
+    protected void onBootCompleted() {
+        mHandler.sendEmptyMessage(MSG_ON_BOOT_COMPLETED);
+    }
+
+    @Override
+    public void onTabletModeChanged(long whenNanos, boolean inTabletMode) {
+        if (DEBUG) {
+            Slog.d(TAG, "onTabletModeChanged(" + whenNanos + ", " + inTabletMode + ")");
+        }
+
+        if (inTabletMode && mInTabletMode != InputManager.SWITCH_STATE_ON
+                || !inTabletMode && mInTabletMode != InputManager.SWITCH_STATE_OFF) {
+            mInTabletMode = inTabletMode ?
+                    InputManager.SWITCH_STATE_ON : InputManager.SWITCH_STATE_OFF;
+            processKeyboardState();
+        }
+    }
+
+    // Shoud only be called on the handler thread
+    private void init() {
+        Context context = mContext;
+        mKeyboardName =
+                context.getString(com.android.internal.R.string.config_packagedKeyboardName);
+        if (TextUtils.isEmpty(mKeyboardName)) {
+            if (DEBUG) {
+                Slog.d(TAG, "No packaged keyboard name given.");
+            }
+            return;
+        }
+
+        LocalBluetoothManager bluetoothManager = LocalBluetoothManager.getInstance(context, null);
+        if (bluetoothManager == null)  {
+            if (DEBUG) {
+                Slog.e(TAG, "Failed to retrieve LocalBluetoothManager instance");
+            }
+            return;
+        }
+        mEnabled = true;
+        mCachedDeviceManager = bluetoothManager.getCachedDeviceManager();
+        mLocalBluetoothAdapter = bluetoothManager.getBluetoothAdapter();
+        mProfileManager = bluetoothManager.getProfileManager();
+        bluetoothManager.getEventManager().registerCallback(new BluetoothCallbackHandler());
+
+        InputManager im = (InputManager) context.getSystemService(Context.INPUT_SERVICE);
+        im.registerOnTabletModeChangedListener(this, mHandler);
+        mInTabletMode = im.isInTabletMode();
+
+        processKeyboardState();
+        mUIHandler = new KeyboardUIHandler();
+    }
+
+    // Should only be called on the handler thread
+    private void processKeyboardState() {
+        mHandler.removeMessages(MSG_PROCESS_KEYBOARD_STATE);
+
+        if (!mEnabled) {
+            mState = STATE_NOT_ENABLED;
+            return;
+        }
+
+        if (!mBootCompleted) {
+            mState = STATE_WAITING_FOR_BOOT_COMPLETED;
+            return;
+        }
+
+        if (mInTabletMode != InputManager.SWITCH_STATE_OFF) {
+            if (mState == STATE_WAITING_FOR_DEVICE_DISCOVERY) {
+                stopScanning();
+            }
+            mState = STATE_WAITING_FOR_TABLET_MODE_EXIT;
+            return;
+        }
+
+        final int btState = mLocalBluetoothAdapter.getState();
+        if (btState == BluetoothAdapter.STATE_TURNING_ON || btState == BluetoothAdapter.STATE_ON
+                && mState == STATE_WAITING_FOR_BLUETOOTH) {
+            // If we're waiting for bluetooth but it has come on in the meantime, or is coming
+            // on, just dismiss the dialog. This frequently happens during device startup.
+            mUIHandler.sendEmptyMessage(MSG_DISMISS_BLUETOOTH_DIALOG);
+        }
+
+        if (btState == BluetoothAdapter.STATE_TURNING_ON) {
+            mState = STATE_WAITING_FOR_BLUETOOTH;
+            // Wait for bluetooth to fully come on.
+            return;
+        }
+
+        if (btState != BluetoothAdapter.STATE_ON) {
+            mState = STATE_WAITING_FOR_BLUETOOTH;
+            showBluetoothDialog();
+            return;
+        }
+
+        CachedBluetoothDevice device = getPairedKeyboard();
+        if ((mState == STATE_WAITING_FOR_TABLET_MODE_EXIT || mState == STATE_WAITING_FOR_BLUETOOTH)
+                && device != null) {
+            // If we're just coming out of tablet mode or BT just turned on,
+            // then we want to go ahead and automatically connect to the
+            // keyboard. We want to avoid this in other cases because we might
+            // be spuriously called after the user has manually disconnected
+            // the keyboard, meaning we shouldn't try to automtically connect
+            // it again.
+            mState = STATE_PAIRED;
+            device.connect(false);
+            return;
+        }
+
+        device = getDiscoveredKeyboard();
+        if (device != null) {
+            mState = STATE_PAIRING;
+            device.startPairing();
+        } else {
+            mState = STATE_WAITING_FOR_DEVICE_DISCOVERY;
+            startScanning();
+        }
+    }
+
+    // Should only be called on the handler thread
+    public void onBootCompletedInternal() {
+        mBootCompleted = true;
+        mBootCompletedTime = SystemClock.uptimeMillis();
+        if (mState == STATE_WAITING_FOR_BOOT_COMPLETED) {
+            processKeyboardState();
+        }
+    }
+
+    // Should only be called on the handler thread
+    private void showBluetoothDialog() {
+        if (isUserSetupComplete()) {
+            long now = SystemClock.uptimeMillis();
+            long earliestDialogTime = mBootCompletedTime + BLUETOOTH_START_DELAY_MILLIS;
+            if (earliestDialogTime < now) {
+                mUIHandler.sendEmptyMessage(MSG_SHOW_BLUETOOTH_DIALOG);
+            } else {
+                mHandler.sendEmptyMessageAtTime(MSG_PROCESS_KEYBOARD_STATE, earliestDialogTime);
+            }
+        } else {
+            // If we're in setup wizard and the keyboard is docked, just automatically enable BT.
+            mLocalBluetoothAdapter.enable();
+        }
+    }
+
+    private boolean isUserSetupComplete() {
+        ContentResolver resolver = mContext.getContentResolver();
+        return Secure.getIntForUser(
+                resolver, Secure.USER_SETUP_COMPLETE, 0, UserHandle.USER_CURRENT) != 0;
+    }
+
+    private CachedBluetoothDevice getPairedKeyboard() {
+        Set<BluetoothDevice> devices = mLocalBluetoothAdapter.getBondedDevices();
+        for (BluetoothDevice d : devices) {
+            if (mKeyboardName.equals(d.getName())) {
+                return getCachedBluetoothDevice(d);
+            }
+        }
+        return null;
+    }
+
+    private CachedBluetoothDevice getDiscoveredKeyboard() {
+        Collection<CachedBluetoothDevice> devices = mCachedDeviceManager.getCachedDevicesCopy();
+        for (CachedBluetoothDevice d : devices) {
+            if (d.getName().equals(mKeyboardName)) {
+                return d;
+            }
+        }
+        return null;
+    }
+
+
+    private CachedBluetoothDevice getCachedBluetoothDevice(BluetoothDevice d) {
+        CachedBluetoothDevice cachedDevice = mCachedDeviceManager.findDevice(d);
+        if (cachedDevice == null) {
+            cachedDevice = mCachedDeviceManager.addDevice(
+                    mLocalBluetoothAdapter, mProfileManager, d);
+        }
+        return cachedDevice;
+    }
+
+    private void startScanning() {
+        BluetoothLeScanner scanner = mLocalBluetoothAdapter.getBluetoothLeScanner();
+        ScanFilter filter = (new ScanFilter.Builder()).setDeviceName(mKeyboardName).build();
+        ScanSettings settings = (new ScanSettings.Builder())
+            .setCallbackType(ScanSettings.CALLBACK_TYPE_ALL_MATCHES)
+            .setNumOfMatches(ScanSettings.MATCH_NUM_ONE_ADVERTISEMENT)
+            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
+            .setReportDelay(0)
+            .build();
+        mScanCallback = new KeyboardScanCallback();
+        scanner.startScan(Arrays.asList(filter), settings, mScanCallback);
+    }
+
+    private void stopScanning() {
+        if (mScanCallback != null) {
+            mLocalBluetoothAdapter.getBluetoothLeScanner().stopScan(mScanCallback);
+            mScanCallback = null;
+        }
+    }
+
+    // Should only be called on the handler thread
+    private void onDeviceAddedInternal(CachedBluetoothDevice d) {
+        if (mState == STATE_WAITING_FOR_DEVICE_DISCOVERY && d.getName().equals(mKeyboardName)) {
+            stopScanning();
+            d.startPairing();
+            mState = STATE_PAIRING;
+        }
+    }
+
+    // Should only be called on the handler thread
+    private void onBluetoothStateChangedInternal(int bluetoothState) {
+        if (bluetoothState == BluetoothAdapter.STATE_ON && mState == STATE_WAITING_FOR_BLUETOOTH) {
+            processKeyboardState();
+        }
+    }
+
+    // Should only be called on the handler thread
+    private void onDeviceBondStateChangedInternal(CachedBluetoothDevice d, int bondState) {
+        if (d.getName().equals(mKeyboardName) && bondState == BluetoothDevice.BOND_BONDED) {
+            // We don't need to manually connect to the device here because it will automatically
+            // try to connect after it has been paired.
+            mState = STATE_PAIRED;
+        }
+    }
+
+    // Should only be called on the handler thread
+    private void onBleScanFailedInternal() {
+        mScanCallback = null;
+        if (mState == STATE_WAITING_FOR_DEVICE_DISCOVERY) {
+            mState = STATE_DEVICE_NOT_FOUND;
+        }
+    }
+
+    private final class KeyboardUIHandler extends Handler {
+        public KeyboardUIHandler() {
+            super(Looper.getMainLooper(), null, true /*async*/);
+        }
+        @Override
+        public void handleMessage(Message msg) {
+            switch(msg.what) {
+                case MSG_SHOW_BLUETOOTH_DIALOG: {
+                    DialogInterface.OnClickListener listener = new BluetoothDialogClickListener();
+                    mDialog = new BluetoothDialog(mContext);
+                    mDialog.setTitle(R.string.enable_bluetooth_title);
+                    mDialog.setMessage(R.string.enable_bluetooth_message);
+                    mDialog.setPositiveButton(R.string.enable_bluetooth_confirmation_ok, listener);
+                    mDialog.setNegativeButton(android.R.string.cancel, listener);
+                    mDialog.show();
+                    break;
+                }
+                case MSG_DISMISS_BLUETOOTH_DIALOG: {
+                    if (mDialog != null) {
+                        mDialog.dismiss();
+                        mDialog = null;
+                    }
+                    break;
+                }
+            }
+        }
+    }
+
+    private final class KeyboardHandler extends Handler {
+        public KeyboardHandler(Looper looper) {
+            super(looper, null, true /*async*/);
+        }
+
+        @Override
+        public void handleMessage(Message msg) {
+            switch(msg.what) {
+                case MSG_INIT: {
+                    init();
+                    break;
+                }
+                case MSG_ON_BOOT_COMPLETED: {
+                    onBootCompletedInternal();
+                    break;
+                }
+                case MSG_PROCESS_KEYBOARD_STATE: {
+                    processKeyboardState();
+                    break;
+                }
+                case MSG_ENABLE_BLUETOOTH: {
+                    boolean enable = msg.arg1 == 1;
+                    if (enable) {
+                        mLocalBluetoothAdapter.enable();
+                    } else {
+                        mState = STATE_USER_CANCELLED;
+                    }
+                }
+                case MSG_ON_BLUETOOTH_STATE_CHANGED: {
+                    int bluetoothState = msg.arg1;
+                    onBluetoothStateChangedInternal(bluetoothState);
+                    break;
+                }
+                case MSG_ON_DEVICE_BOND_STATE_CHANGED: {
+                    CachedBluetoothDevice d = (CachedBluetoothDevice)msg.obj;
+                    int bondState = msg.arg1;
+                    onDeviceBondStateChangedInternal(d, bondState);
+                    break;
+                }
+                case MSG_ON_BLUETOOTH_DEVICE_ADDED: {
+                    BluetoothDevice d = (BluetoothDevice)msg.obj;
+                    CachedBluetoothDevice cachedDevice = getCachedBluetoothDevice(d);
+                    onDeviceAddedInternal(cachedDevice);
+                    break;
+
+                }
+                case MSG_ON_BLE_SCAN_FAILED: {
+                    onBleScanFailedInternal();
+                    break;
+                }
+            }
+        }
+    }
+
+    private final class BluetoothDialogClickListener implements DialogInterface.OnClickListener {
+        @Override
+        public void onClick(DialogInterface dialog, int which) {
+            int enable = DialogInterface.BUTTON_POSITIVE == which ? 1 : 0;
+            mHandler.obtainMessage(MSG_ENABLE_BLUETOOTH, enable, 0).sendToTarget();
+            mDialog = null;
+        }
+    }
+
+    private final class KeyboardScanCallback extends ScanCallback {
+        @Override
+        public void onBatchScanResults(List<ScanResult> results) {
+            if (DEBUG) {
+                Slog.d(TAG, "onBatchScanResults(" + results.size() + ")");
+            }
+            if (!results.isEmpty()) {
+                BluetoothDevice bestDevice = results.get(0).getDevice();
+                int bestRssi = results.get(0).getRssi();
+                final int N = results.size();
+                for (int i = 0; i < N; i++) {
+                    ScanResult r = results.get(i);
+                    if (r.getRssi() > bestRssi) {
+                        bestDevice = r.getDevice();
+                    }
+                }
+                mHandler.obtainMessage(MSG_ON_BLUETOOTH_DEVICE_ADDED, bestDevice).sendToTarget();
+            }
+        }
+
+        @Override
+        public void onScanFailed(int errorCode) {
+            if (DEBUG) {
+                Slog.d(TAG, "onScanFailed(" + errorCode + ")");
+            }
+            mHandler.obtainMessage(MSG_ON_BLE_SCAN_FAILED).sendToTarget();
+        }
+
+        @Override
+        public void onScanResult(int callbackType, ScanResult result) {
+            if (DEBUG) {
+                Slog.d(TAG, "onScanResult(" + callbackType + ", " + result + ")");
+            }
+            mHandler.obtainMessage(MSG_ON_BLUETOOTH_DEVICE_ADDED,
+                    result.getDevice()).sendToTarget();
+        }
+    }
+
+    private final class BluetoothCallbackHandler implements BluetoothCallback {
+        @Override
+        public void onBluetoothStateChanged(int bluetoothState) {
+            mHandler.obtainMessage(MSG_ON_BLUETOOTH_STATE_CHANGED,
+                    bluetoothState, 0).sendToTarget();
+        }
+
+        @Override
+        public void onDeviceBondStateChanged(CachedBluetoothDevice cachedDevice, int bondState) {
+            mHandler.obtainMessage(MSG_ON_DEVICE_BOND_STATE_CHANGED,
+                    bondState, 0, cachedDevice).sendToTarget();
+        }
+
+        @Override
+        public void onDeviceAdded(CachedBluetoothDevice cachedDevice) { }
+        @Override
+        public void onDeviceDeleted(CachedBluetoothDevice cachedDevice) { }
+        @Override
+        public void onScanningStateChanged(boolean started) { }
+        @Override
+        public void onConnectionStateChanged(CachedBluetoothDevice cachedDevice, int state) { }
+    }
+
+    private static String stateToString(int state) {
+        switch (state) {
+            case STATE_NOT_ENABLED:
+                return "STATE_NOT_ENABLED";
+            case STATE_WAITING_FOR_BOOT_COMPLETED:
+                return "STATE_WAITING_FOR_BOOT_COMPLETED";
+            case STATE_WAITING_FOR_TABLET_MODE_EXIT:
+                return "STATE_WAITING_FOR_TABLET_MODE_EXIT";
+            case STATE_WAITING_FOR_DEVICE_DISCOVERY:
+                return "STATE_WAITING_FOR_DEVICE_DISCOVERY";
+            case STATE_WAITING_FOR_BLUETOOTH:
+                return "STATE_WAITING_FOR_BLUETOOTH";
+            case STATE_WAITING_FOR_STATE_PAIRED:
+                return "STATE_WAITING_FOR_STATE_PAIRED";
+            case STATE_PAIRING:
+                return "STATE_PAIRING";
+            case STATE_PAIRED:
+                return "STATE_PAIRED";
+            case STATE_USER_CANCELLED:
+                return "STATE_USER_CANCELLED";
+            case STATE_DEVICE_NOT_FOUND:
+                return "STATE_DEVICE_NOT_FOUND";
+            case STATE_UNKNOWN:
+            default:
+                return "STATE_UNKNOWN";
+        }
+    }
+}