目前流行的蓝牙4.0标准包括传统的蓝牙(BT)和低功耗蓝牙模块(BLE)。
这里扫描的是传统蓝牙模块，先给出扫描结果：
preview.gif
一，扫描
Android扫描蓝牙设备是通过BluetoothAdapter启动蓝牙搜索，然后通过广播接收扫描的结果，其主要代码如下：
1，获取BluetoothAdapter
可通过单例模式直接获取
val btAdapt = BluetoothAdapter.getDefaultAdapter()
2，开始扫描
if (!btAdapt.isDiscovering) {
it.startDiscovery()
}
3,注册广播
val intent = IntentFilter()
intent.apply {
addAction(BluetoothDevice.ACTION_FOUND)
addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED)
addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED)
addAction(BluetoothAdapter.ACTION_STATE_CHANGED)
priority = IntentFilter.SYSTEM_HIGH_PRIORITY
}
registerReceiver(searchDevices, intent)
private val searchDevices: BroadcastReceiver = object : BroadcastReceiver() {
override fun onReceive(context: Context, intent: Intent) {
when (intent.action) {
BluetoothAdapter.ACTION_STATE_CHANGED -> {
LogUtil.LOGE("ACTION_STATE_CHANGED")
}
BluetoothDevice.ACTION_FOUND -> { //found device
val device =
intent.getParcelableExtra<BluetoothDevice>(BluetoothDevice.EXTRA_DEVICE)
if (!device.name.isNullOrEmpty()) {
// 得到设备对象
mData.add(device)
adapter.notifyDataSetChanged()
}
}
BluetoothAdapter.ACTION_DISCOVERY_STARTED -> {
ToastUtil.show("正在扫描")
}
BluetoothAdapter.ACTION_DISCOVERY_FINISHED -> {
ToastUtil.show("扫描完成，点击列表中的设备来尝试连接")
}
}
}
}
拿到设备对象后即可在列表中展示，最后别忘了取消注册广播
二，获取蓝牙设备类型
上面获取到的设备对象BluetoothDevice 有 device.getType()方法。查看源码可知，该方法返回的类型有
/**
* Bluetooth device type, Unknown 未知类型
*/
public static final int DEVICE_TYPE_UNKNOWN = 0;
/**
* Bluetooth device type, Classic - BR/EDR devices 传统类型
*/
public static final int DEVICE_TYPE_CLASSIC = 1;
/**
* Bluetooth device type, Low Energy - LE-only ble类型
*/
public static final int DEVICE_TYPE_LE = 2;
/**
* Bluetooth device type, Dual Mode - BR/EDR/LE 传统和ble双重类型
*/
public static final int DEVICE_TYPE_DUAL = 3;
我们来看一下手机自带的蓝牙扫描到的结果：
mobile_list.png
把device.getType()方法返回值和上面的做对比，可以发现该方法无法区分设备是手机类型，电脑类型还是耳机类型。
那么Android系统是如何区分的呢？
命令行下输入如下命令：
adb shell dumpsys window | findstr mCurrentFocus
查看手机系统自带的蓝牙扫描界面结果如下：
mCurrentFocus=Window{43e2635 u0 com.android.settings/com.android.settings.Settings$BluetoothSettingsActivity}
因此查看android源码找到BluetoothSettingsActivity即可查看其如何实现，这里源码就不做深究，获取类型方式如下：
// 获取类型对应的图标资源
int deviceTypeImg = BtUtil.getDeviceType(device.getBluetoothClass());
holder.ivType.setImageResource(deviceTypeImg);
用到的工具类是在系统源码基础上做了修改，代码如下：
public class BtUtil {
public static final int PROFILE_HEADSET = 0;
public static final int PROFILE_A2DP = 1;
public static final int PROFILE_OPP = 2;
public static final int PROFILE_HID = 3;
public static final int PROFILE_PANU = 4;
public static final int PROFILE_NAP = 5;
public static final int PROFILE_A2DP_SINK = 6;
public static int getDeviceType(BluetoothClass bluetoothClass) {
if (bluetoothClass == null) {
return R.drawable.ic_settings_bluetooth;
}
switch (bluetoothClass.getMajorDeviceClass()) {
case BluetoothClass.Device.Major.COMPUTER:
return R.drawable.ic_bt_laptop;
case BluetoothClass.Device.Major.PHONE:
return R.drawable.ic_bt_cellphone;
case BluetoothClass.Device.Major.PERIPHERAL:
return R.drawable.ic_bt_misc_hid;
case BluetoothClass.Device.Major.IMAGING:
return R.drawable.ic_bt_imaging;
default:
if (BtUtil.doesClassMatch(bluetoothClass, PROFILE_HEADSET))
return R.drawable.ic_bt_headset_hfp;
else if (BtUtil.doesClassMatch(bluetoothClass, PROFILE_A2DP)) {
return R.drawable.ic_bt_headphones_a2dp;
} else {
return R.drawable.ic_settings_bluetooth;
}
}
}
public static boolean doesClassMatch(BluetoothClass bluetoothClass, int profile) {
if (profile == PROFILE_A2DP) {
if (bluetoothClass.hasService(BluetoothClass.Service.RENDER)) {
return true;
}
// By the A2DP spec, sinks must indicate the RENDER service.
// However we found some that do not (Chordette). So lets also
// match on some other class bits.
switch (bluetoothClass.getDeviceClass()) {
case BluetoothClass.Device.AUDIO_VIDEO_HIFI_AUDIO:
case BluetoothClass.Device.AUDIO_VIDEO_HEADPHONES:
case BluetoothClass.Device.AUDIO_VIDEO_LOUDSPEAKER:
case BluetoothClass.Device.AUDIO_VIDEO_CAR_AUDIO:
return true;
default:
return false;
}
} else if (profile == PROFILE_A2DP_SINK) {
if (bluetoothClass.hasService(BluetoothClass.Service.CAPTURE)) {
return true;
}
// By the A2DP spec, srcs must indicate the CAPTURE service.
// However if some device that do not, we try to
// match on some other class bits.
switch (bluetoothClass.getDeviceClass()) {
case BluetoothClass.Device.AUDIO_VIDEO_HIFI_AUDIO:
case BluetoothClass.Device.AUDIO_VIDEO_SET_TOP_BOX:
case BluetoothClass.Device.AUDIO_VIDEO_VCR:
return true;
default:
return false;
}
} else if (profile == PROFILE_HEADSET) {
// The render service class is required by the spec for HFP, so is a
// pretty good signal
if (bluetoothClass.hasService(BluetoothClass.Service.RENDER)) {
return true;
}
// Just in case they forgot the render service class
switch (bluetoothClass.getDeviceClass()) {
case BluetoothClass.Device.AUDIO_VIDEO_HANDSFREE:
case BluetoothClass.Device.AUDIO_VIDEO_WEARABLE_HEADSET:
case BluetoothClass.Device.AUDIO_VIDEO_CAR_AUDIO:
return true;
default:
return false;
}
} else if (profile == PROFILE_OPP) {
if (bluetoothClass.hasService(BluetoothClass.Service.OBJECT_TRANSFER)) {
return true;
}
switch (bluetoothClass.getDeviceClass()) {
case BluetoothClass.Device.COMPUTER_UNCATEGORIZED:
case BluetoothClass.Device.COMPUTER_DESKTOP:
case BluetoothClass.Device.COMPUTER_SERVER:
case BluetoothClass.Device.COMPUTER_LAPTOP:
case BluetoothClass.Device.COMPUTER_HANDHELD_PC_PDA:
case BluetoothClass.Device.COMPUTER_PALM_SIZE_PC_PDA:
case BluetoothClass.Device.COMPUTER_WEARABLE:
case BluetoothClass.Device.PHONE_UNCATEGORIZED:
case BluetoothClass.Device.PHONE_CELLULAR:
case BluetoothClass.Device.PHONE_CORDLESS:
case BluetoothClass.Device.PHONE_SMART:
case BluetoothClass.Device.PHONE_MODEM_OR_GATEWAY:
case BluetoothClass.Device.PHONE_ISDN:
return true;
default:
return false;
}
} else if (profile == PROFILE_HID) {
return (bluetoothClass.getDeviceClass() & BluetoothClass.Device.Major.PERIPHERAL) == BluetoothClass.Device.Major.PERIPHERAL;
} else if (profile == PROFILE_PANU || profile == PROFILE_NAP) {
// No good way to distinguish between the two, based on class bits.
if (bluetoothClass.hasService(BluetoothClass.Service.NETWORKING)) {
return true;
}
return (bluetoothClass.getDeviceClass() & BluetoothClass.Device.Major.NETWORKING) == BluetoothClass.Device.Major.NETWORKING;
} else {
return false;
}
}
}
最终实现效果如下图：
preview.gif
