目录

一，背景介绍

二，技术方案

2.1 获取BluetoothHidDevice实例

2.2 注册/解除注册HID实例

2.3 Hid report description描述符生成工具

2.4 通过sendReport想host发送按键信息

一，背景介绍

        日常生活中，各种物理遥控器和鼠标等设备，需要摆放和携带，便捷性有待考验。根据蓝牙HID特性，可以用蓝牙协议模仿鼠标事件，来实现空中鼠标等功能。

二，技术方案

        自Android 9开放BluetoothHidDevice功能后，Android平台可以很简单的通过BluetoothHidDevice模拟键盘鼠标等蓝牙hid device角色。

2.1 获取BluetoothHidDevice实例

 BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); bluetoothAdapter.setName("MOUSE BT"); bluetoothAdapter.getProfileProxy(context,mProfileServiceListener,BluetoothProfile.HID_DEVICE);

2.2 注册/解除注册HID实例

讯享网

讯享网 public static BluetoothProfile.ServiceListener mProfileServiceListener = new BluetoothProfile.ServiceListener() { @Override public void onServiceDisconnected(int profile) { Log.e(TAG, "hid onServiceDisconnected"); if (profile == BluetoothProfile.HID_DEVICE) { mHidDevice.unregisterApp(); } } @SuppressLint("NewApi") @Override public void onServiceConnected(int profile, BluetoothProfile proxy) { Log.e(TAG, "hid onServiceConnected"); bluetoothProfile = proxy; if (profile == BluetoothProfile.HID_DEVICE) { mHidDevice = (BluetoothHidDevice) proxy; HidConsts.HidDevice = mHidDevice; BluetoothHidDeviceAppSdpSettings sdp = new BluetoothHidDeviceAppSdpSettings(HidConsts.NAME, HidConsts.DESCRIPTION, HidConsts.PROVIDER, BluetoothHidDevice.SUBCLASS1_COMBO, HidConsts.Descriptor); mHidDevice.registerApp(sdp, null, null, Executors.newCachedThreadPool(), mCallback); } } };

        在获取到BluetoothHidDevice实例后通过registerApp注册hid device，此时hid host角色会被禁用，因此在不需要hid device功能时要及时解除hid device的注册。

        registerApp函数中最重要的一个参数BluetoothHidDeviceAppSdpSettings，主要是给对端host提供hid device角色的名称，描述信息，供应商信息，以及Hid device的Reports Descriptor。

2.3 Hid report description描述符生成工具

参考文章《官网HID描述符工具》

    public class HidConfig {
        
        public final static String NAME = "My Keyboard";
     
        public final static String DESCRIPTION = "Lgd's Keyboard";
     
        public final static String PROVIDER = "Lgd";
     
        public static final byte[] KEYBOARD_DESCRIPTOR =
                {
                        (byte) 0x05, (byte) 0x01,                    // USAGE_PAGE (Generic Desktop)
                        (byte) 0x09, (byte) 0x06,                    // USAGE (Keyboard)
                        (byte) 0xa1, (byte) 0x01,                    // COLLECTION (Application)
                        (byte) 0x85, (byte) 0x02,                    //REPORT_ID (2)
                        (byte) 0x05, (byte) 0x07,                    //   USAGE_PAGE (Keyboard)
                        (byte) 0x19, (byte) 0xe0,                    //   USAGE_MINIMUM (Keyboard LeftControl)
                        (byte) 0x29, (byte) 0xe7,                    //   USAGE_MAXIMUM (Keyboard Right GUI)
                        (byte) 0x15, (byte) 0x00,                    //   LOGICAL_MINIMUM (0)
                        (byte) 0x25, (byte) 0x01,                    //   LOGICAL_MAXIMUM (1)
                        (byte) 0x75, (byte) 0x01,                    //   REPORT_SIZE (1)
                        (byte) 0x95, (byte) 0x08,                    //   REPORT_COUNT (8)
                        (byte) 0x81, (byte) 0x02,                    //   INPUT (Data,Var,Abs)
                        (byte) 0x95, (byte) 0x01,                    //   REPORT_COUNT (1)
                        (byte) 0x75, (byte) 0x08,                    //   REPORT_SIZE (8)
                        (byte) 0x81, (byte) 0x03,                    //   INPUT (Cnst,Var,Abs)
                        (byte) 0x95, (byte) 0x05,                    //   REPORT_COUNT (5)
                        (byte) 0x75, (byte) 0x01,                    //   REPORT_SIZE (1)
                        (byte) 0x05, (byte) 0x08,                    //   USAGE_PAGE (LEDs)
                        (byte) 0x19, (byte) 0x01,                    //   USAGE_MINIMUM (Num Lock)
                        (byte) 0x29, (byte) 0x05,                    //   USAGE_MAXIMUM (Kana)
                        (byte) 0x91, (byte) 0x02,                    //   OUTPUT (Data,Var,Abs)
                        (byte) 0x95, (byte) 0x01,                    //   REPORT_COUNT (1)
                        (byte) 0x75, (byte) 0x03,                    //   REPORT_SIZE (3)
                        (byte) 0x91, (byte) 0x03,                    //   OUTPUT (Cnst,Var,Abs)
                        (byte) 0x95, (byte) 0x06,                    //   REPORT_COUNT (6)
                        (byte) 0x75, (byte) 0x08,                    //   REPORT_SIZE (8)
                        (byte) 0x15, (byte) 0x00,                    //   LOGICAL_MINIMUM (0)
                        (byte) 0x25, (byte) 0x65,                    //   LOGICAL_MAXIMUM (101)
                        (byte) 0x05, (byte) 0x07,                    //   USAGE_PAGE (Keyboard)
                        (byte) 0x19, (byte) 0x00,                    //   USAGE_MINIMUM (Reserved (no event indicated))
                        (byte) 0x29, (byte) 0x65,                    //   USAGE_MAXIMUM (Keyboard Application)
                        (byte) 0x81, (byte) 0x00,                    //   INPUT (Data,Ary,Abs)
                        (byte) 0xc0                           // END_COLLECTION
                };
     }
     

上面的描述符只是适配键盘，可以不定义report id，如果是多个hid功能复合的设备，例如复合键盘鼠标，就需要再添加鼠标的报告描述符，同时每个功能都需要有对应的report id。

        0x05, 0x01, // USAGE_PAGE (Generic Desktop)
        0x09, 0x02, // USAGE (Mouse)
        0xa1, 0x01, // COLLECTION (Application)
        0x85, 0x01, // REPORT_ID (1)
        0x75, 0x10, // REPORT_SIZE (16)
        0x95, 0x01, // REPORT_COUNT (1)
        0x15, 0x0b, // LOGICAL_MINIMUM (11)
        0x25, 0x1c, // LOGICAL_MAXIMUM (28)
        0x09, 0x30, // USAGE (X)
        0x81, 0x22, // INPUT (Data,Var,Abs,NPrf)
        0xc0, // END_COLLECTION
        0x09, 0x06, // USAGE (Keyboard)
        0xa1, 0x01, // COLLECTION (Application)
        0x85, 0x02, // REPORT_ID (2)
        0x75, 0x08, // REPORT_SIZE (8)
        0x95, 0x01, // REPORT_COUNT (1)
        0x15, 0x00, // LOGICAL_MINIMUM (0)
        0x25, 0x40, // LOGICAL_MAXIMUM (64)
        0x09, 0x31, // USAGE (Y)
        0x81, 0x02, // INPUT (Data,Var,Abs)
        0xc0

2.4 通过sendReport想host发送按键信息

第二个参数是report description中定义的report id，如果没有定义传入0。

第三个参数是按键数据，根据report description，总共有8字节，前2字节是功能键，后6字节是对应的键值信息

        mHidDevice.sendReport(device, 2, new byte[]{0, 0, (byte) code, 0, 0, 0, 0, 0});

需要源码，请私信