蓝牙HID——将android设备变成蓝牙鼠标-触控板（BluetoothHidDevice）

前言

本篇为蓝牙HID系列篇章之一，本篇以红米K30（MIUI13即Android 12）手机作为蓝牙HID设备，可以与电脑、手机、平板等其他蓝牙主机进行配对从而实现鼠标触控板的功能。
蓝牙HID系列篇章：
蓝牙HID——将android设备变成蓝牙键盘（BluetoothHidDevice）
蓝牙HID——android利用手机来解锁电脑/平板/iPhone
蓝牙HID——Android手机注册HID时出现 Could not bind to Bluetooth (HID Device) Service with Intent * 的问题分析

HID开发

Android 9开放了 BluetoothHidDevice 等HID相关的API，通过与系统蓝牙HID服务通信注册成蓝牙HID设备。首先通过 BluetoothProfile.HID_DEVICE 的描述类型得到 BluetoothHidDevice 抽象实例：

private BluetoothAdapter mBtAdapter;private BluetoothHidDevice mHidDevice;private void callBluetooth() {Log.d(TAG, "callBluetooth");mBtAdapter = BluetoothAdapter.getDefaultAdapter();mBtAdapter.getProfileProxy(mContext, new BluetoothProfile.Servicelistener() {@Overridepublic void onServiceConnected(int i, BluetoothProfile bluetoothProfile) {Log.d(TAG, "onServiceConnected:" + i);if (i == BluetoothProfile.HID_DEVICE) {if (!(bluetoothProfile instanceof BluetoothHidDevice)) {Log.e(TAG, "Proxy received but it's not BluetoothHidDevice");return;}mHidDevice = (BluetoothHidDevice) bluetoothProfile;registerBluetoothHid();}}@Overridepublic void onServiceDisconnected(int i) {Log.d(TAG, "onServiceDisconnected:" + i);}}, BluetoothProfile.HID_DEVICE);}

再调用 BluetoothHidDevice.registerApp() 将 Android 设备注册成蓝牙HID设备：

private BluetoothDevice mHostDevice;private final BluetoothHidDeviceAppQosSettings qosSettings= new BluetoothHidDeviceAppQosSettings(BluetoothHidDeviceAppQosSettings.SERVICE_BEST_EFFORT,800, 9, 0, 11250, BluetoothHidDeviceAppQosSettings.MAX);private final BluetoothHidDeviceAppSdpSettings mouseSdpSettings = new BluetoothHidDeviceAppSdpSettings(HidConfig.MOUSE_NAME, HidConfig.DESCRIPTION, HidConfig.PROVIDER,BluetoothHidDevice.SUBCLASS1_MOUSE, HidConfig.MOUSE_COMBO);private void registerBluetoothHid() {if (mHidDevice == null) {Log.e(TAG, "hid device is null");return;}mHidDevice.registerApp(mouseSdpSettings, null, qosSettings, executors.newCachedThreadPool(), new BluetoothHidDevice.Callback() {@Overridepublic void onAppStatusChanged(BluetoothDevice pluggedDevice, boolean registered) {Log.d(TAG, "onAppStatusChanged:" + (pluggedDevice != null ? pluggedDevice.getName() : "null") + " registered:" + registered);if (registered) {Log.d(TAG, "paired devices: " + mHidDevice.getConnectionState(pluggedDevice));if (pluggedDevice != null && mHidDevice.getConnectionState(pluggedDevice) != BluetoothProfile.STATE_CONNECTED) {boolean result = mHidDevice.connect(pluggedDevice);Log.d(TAG, "hidDevice connect:" + result);}}if (mBluetoothHidStateListener != null) {mBluetoothHidStateListener.onRegisterStateChanged(registered, pluggedDevice != null);}}@Overridepublic void onConnectionStateChanged(BluetoothDevice device, int state) {Log.d(TAG, "onConnectionStateChanged:" + device + " state:" + state);if (state == BluetoothProfile.STATE_CONNECTED) {mHostDevice = device;}if (state == BluetoothProfile.STATE_DISCONNECTED) {mHostDevice = null;}if (mBluetoothHidStateListener != null) {mBluetoothHidStateListener.onConnectionStateChanged(state);}}});}

蓝牙鼠标Mouse的描述信息如下，主要 为 MOUSE_COMBO 的描述协议，正确的描述协议才能成功与其他设备通信。

public class HidConfig {public final static String MOUSE_NAME = "VV Mouse";public final static String DESCRIPTION = "VV for you";public final static String PROVIDER = "VV";public static final byte[] MOUSE_COMBO = {(byte) 0x05, (byte) 0x01, // USAGE_PAGE (Generic Desktop)(byte) 0x09, (byte) 0x02, // USAGE (Mouse)(byte) 0xa1, (byte) 0x01, // COLLECTION (Application)(byte) 0x85, (byte) 0x04, // REPORT_ID (4)(byte) 0x09, (byte) 0x01, // USAGE (Pointer)(byte) 0xa1, (byte) 0x00, // COLLECTION (Physical)(byte) 0x05, (byte) 0x09, // USAGE_PAGE (Button)(byte) 0x19, (byte) 0x01, // USAGE_MINIMUM (Button 1)(byte) 0x29, (byte) 0x02, // USAGE_MAXIMUM (Button 2)(byte) 0x15, (byte) 0x00, // LOGICAL_MINIMUM (0)(byte) 0x25, (byte) 0x01, // LOGICAL_MAXIMUM (1)(byte) 0x95, (byte) 0x03, // REPORT_COUNT (3)(byte) 0x75, (byte) 0x01, // REPORT_SIZE (1)(byte) 0x81, (byte) 0x02, // INPUT (Data,Var,Abs)(byte) 0x95, (byte) 0x01, // REPORT_COUNT (1)(byte) 0x75, (byte) 0x05, // REPORT_SIZE (5)(byte) 0x81, (byte) 0x03, // INPUT (Cnst,Var,Abs)(byte) 0x05, (byte) 0x01, // USAGE_PAGE (Generic Desktop)(byte) 0x09, (byte) 0x30, // USAGE (X)(byte) 0x09, (byte) 0x31, // USAGE (Y)(byte) 0x09, (byte) 0x38, // USAGE (Wheel)(byte) 0x15, (byte) 0x81, // LOGICAL_MINIMUM (-127)(byte) 0x25, (byte) 0x7F, // LOGICAL_MAXIMUM (127)(byte) 0x75, (byte) 0x08, // REPORT_SIZE (8)(byte) 0x95, (byte) 0x03, // REPORT_COUNT (3)(byte) 0x81, (byte) 0x06, // INPUT (Data,Var,Rel)//水平滚轮(byte) 0x05, (byte) 0x0c, // USAGE_PAGE (Consumer Devices)(byte) 0x0a, (byte) 0x38, (byte) 0x02, // USAGE (AC Pan)(byte) 0x15, (byte) 0x81, // LOGICAL_MINIMUM (-127)(byte) 0x25, (byte) 0x7f, // LOGICAL_MAXIMUM (127)(byte) 0x75, (byte) 0x08, // REPORT_SIZE (8)(byte) 0x95, (byte) 0x01, // REPORT_COUNT (1)(byte) 0x81, (byte) 0x06, // INPUT (Data,Var,Rel)(byte) 0xc0, // END_COLLECTION(byte) 0xc0, // END_COLLECTION};

在注册完成后启动设备发现，让HID能被其他设备发现，下面ActivityResultLauncher.launch(new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE) 相当于调用 BluetoothAdapter.setScanMode() 的隐藏API

private ActivityResultLauncher<Intent> mActivityResultLauncher;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_mouse);mActivityResultLauncher = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), result -> {Log.d(TAG, "onActivityResult:" + result.toString());});}@Overridepublic void onRegisterStateChanged(boolean registered, boolean hasDevice) {if (registered) {if (!hasDevice) {// startActivityForResult(new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE), 1);mActivityResultLauncher.launch(new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE));}}}

ActivityResultLauncher 的相关方法也可用 startActivityForResult(new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE), REQUEST_CODE) 来替代，但 startActivityForResult() 是废弃的方法，不建议使用。
接下来与蓝牙主机（电脑、手机等）进行蓝牙配对，已配对过需要取消配对。配对完成即可实现对蓝牙主机的鼠标触摸控制。

手势识别

手势识别通过对触摸事件以及手势监听进行各种手势的判断（移动鼠标、左键单击、左键双击、右键双指单击、双指垂直/水平滚动）。

CustomMotionListener customMotionListener = new CustomMotionListener(this, mBluetoothHidManager); findViewById(R.id.layout_touch).setOnTouchListener(customMotionListener);

手势逻辑处理代码如下：

package com.example.bluetoothproject;import android.content.Context; import android.view.GestureDetector; import android.view.MotionEvent; import android.view.View; import android.view.ViewConfiguration;import org.apache.commons.lang3.concurrent.BasicThreadFactory;import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.ScheduledThreadPoolExecutor; import java.util.concurrent.TimeUnit;public class CustomMotionListener implements View.OnTouchListener, GestureDetector.OnGestureListener, GestureDetector.OnDoubleTapListener {private final GestureDetector mGestureDetector;private BluetoothHidManager mBluetoothHidManager;private int mPointCount;private long mDoubleFingerTime;private final ScheduledExecutorService mExecutorService;private float mPreX;private float mPreY;private boolean mLongPress;public CustomMotionListener(Context context, BluetoothHidManager bluetoothHidManager) {mBluetoothHidManager = bluetoothHidManager;mGestureDetector = new GestureDetector(context, this);mGestureDetector.setOnDoubleTapListener(this);mExecutorService = new ScheduledThreadPoolExecutor(1,new BasicThreadFactory.Builder().namingPattern("mouse-schedule-pool-%d").daemon(true).build());}@Overridepublic boolean onSingleTapConfirmed(MotionEvent e) {return false;}@Overridepublic boolean onDoubleTap(MotionEvent e) {return false;}@Overridepublic boolean onDoubleTapEvent(MotionEvent e) {//左键单指双击（选中文本的效果）if (e.getAction() == MotionEvent.ACTION_DOWN) {mBluetoothHidManager.sendLeftClick(true);} else if (e.getAction() == MotionEvent.ACTION_UP) {mBluetoothHidManager.sendLeftClick(false);}return true;}@Overridepublic boolean onDown(MotionEvent e) {return false;}@Overridepublic void onShowPress(MotionEvent e) {}@Overridepublic boolean onSingleTapUp(MotionEvent e) {//左键单击mBluetoothHidManager.sendLeftClick(true);mBluetoothHidManager.sendLeftClick(false);return true;}@Overridepublic boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {//双指滚动，x为水平滚动，y为垂直滚动，消抖处理if (mPointCount == 2) {if (Math.abs(distanceX) > Math.abs(distanceY)) {distanceX = distanceX > 0 ? 1 : distanceX < 0 ? -1 : 0;distanceY = 0;} else {distanceY = distanceY > 0 ? -1 : distanceY < 0 ? 1 : 0;distanceX = 0;}mBluetoothHidManager.sendWheel((byte) (distanceX), (byte) (distanceY));}return false;}@Overridepublic void onLongPress(MotionEvent e) {//单键长按效果mBluetoothHidManager.sendLeftClick(true);mLongPress = true;}@Overridepublic boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {return false;}@Overridepublic boolean onTouch(View v, MotionEvent event) {float x = event.getX();float y = event.getY();if (mGestureDetector.onTouchEvent(event)) {return true;}mPointCount = event.getPointerCount();switch (event.getActionMasked()) {case MotionEvent.ACTION_POINTER_DOWN://双指单击代表右键记录时间if (event.getPointerCount() == 2) {mDoubleFingerTime = System.currentTimeMillis();}break;case MotionEvent.ACTION_MOVE://单指代表移动鼠标if (event.getPointerCount() == 1) {float dx = x - mPreX;if (dx > 127) dx = 127;if (dx < -128) dx = -128;float dy = y - mPreY;if (dy > 127) dy = 127;if (dy < -128) dy = -128;mBluetoothHidManager.senMouse((byte) dx, (byte) dy);} else {mBluetoothHidManager.senMouse((byte) 0, (byte) 0);}break;case MotionEvent.ACTION_UP:if (mLongPress) {mBluetoothHidManager.sendLeftClick(false);mLongPress = false;}break;case MotionEvent.ACTION_POINTER_UP://双指按下代表右键if (event.getPointerCount() == 2 && System.currentTimeMillis() - mDoubleFingerTime < ViewConfiguration.getDoubleTapTimeout()) {mBluetoothHidManager.sendRightClick(true);//延时释放避免无效mExecutorService.scheduleWithFixedDelay(new runnable() {@Overridepublic void run() {mBluetoothHidManager.sendRightClick(false);}}, 0, 50, TimeUnit.MILLISECONDS); }break;default:break;}mPreX = x;mPreY = y;return true;} }

向蓝牙主机发送的鼠标触摸按键的报告如下：

private boolean mLeftClick;private boolean mRightClick;public void sendLeftClick(boolean click) {mLeftClick = click;senMouse((byte) 0x00, (byte) 0x00);}public void sendRightClick(boolean click) {mRightClick = click;senMouse((byte) 0x00, (byte) 0x00);}public void senMouse(byte dx, byte dy) {if (mHidDevice == null) {Log.e(TAG, "senMouse failed, hid device is null!");return;}if (mHostDevice == null) {Log.e(TAG, "senMouse failed, hid device is not connected!");return;}byte[] bytes = new byte[5];//bytes[0]字节：bit0: 1表示左键按下 0表示左键抬起 | bit1: 1表示右键按下 0表示右键抬起 | bit2: 1表示中键按下 | bit7～3：补充的常数，无意义，这里为0即可bytes[0] = (byte) (bytes[0] | (mLeftClick ? 1 : 0));bytes[0] = (byte) (bytes[0] | (mRightClick ? 1 : 0) << 1);bytes[1] = dx;bytes[2] = dy;Log.d(TAG, "senMouse Left:" + mLeftClick+ ",Right:" + mRightClick + ",bytes: " + BluetoothUtils.bytesToHexString(bytes));mHidDevice.sendReport(mHostDevice, 4, bytes);}public void sendWheel(byte hWheel, byte vWheel) {if (mHidDevice == null) {Log.e(TAG, "sendWheel failed, hid device is null!");return;}if (mHostDevice == null) {Log.e(TAG, "sendWheel failed, hid device is not connected!");return;}byte[] bytes = new byte[5];bytes[3] = vWheel; //垂直滚轮bytes[4] = hWheel; //水平滚轮Log.d(TAG, "sendWheel vWheel:" + vWheel + ",hWheel：" + hWheel);mHidDevice.sendReport(mHostDevice, 4, bytes);}

效果

实现以上步骤即可将手机变成蓝牙鼠标/触控板，下面是实现的效果：

鼠标移动：

左键单击：

左键单指快速双击：

右键双指单击：

双指垂直上下滚动：

双指水平左右滚动：

完整视频效果展示：

蓝牙HID——将android设备变成蓝牙鼠标/触控板