安卓蓝牙手册

声明

lateinit var bluetoothAdapter: BluetoothAdapter
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter()

方法

// 是否开启蓝牙
bluetoothAdapter.isEnabled
// 开始扫描附近蓝牙设备
bluetoothAdapter.startDiscovery()
// 注册和销毁扫描广播
val intentFilter = IntentFilter(BluetoothDevice.ACTION_FOUND)
registerReceiver(broadcastReceiver, intentFilter)
unregisterReceiver(broadcastReceiver)
var broadcastReceiver = object : BroadcastReceiver() {
	@SuppressLint("MissingPermission")
	override fun onReceive(context: Context?, intent: Intent?) {
		if (intent != null) {
			when (intent.action) {
				BluetoothDevice.ACTION_FOUND -> {
					// Discovery has found a device. Get the BluetoothDevice
					// object and its info from the Intent.
					val device: BluetoothDevice? =
						intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE)
					val deviceName = device?.name
					val deviceHardwareAddress = device?.address // MAC address
					if (deviceName != null) {
						if (device !in devices) {
							devices.add(device)
							println(deviceName)
							println(deviceHardwareAddress)
							scanTv.append(deviceName + '\n')
							scanTv.append(deviceHardwareAddress + '\n')
						}
					}
				}
			}
		}
	}
}
// 连接蓝牙设备并通讯（SPP蓝牙串口型）
val connectThread = ConnectThread(device);
connectThread.start()
private inner class ConnectThread(device: BluetoothDevice) : Thread() {

	private val mmSocket: BluetoothSocket? by lazy(LazyThreadSafetyMode.NONE) {
		device.createInsecureRfcommSocketToServiceRecord(UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"))
	}

	@RequiresApi(Build.VERSION_CODES.M)
	override fun run() {
		// Cancel discovery because it otherwise slows down the connection.

		bluetoothAdapter.cancelDiscovery()

		mmSocket?.let { socket ->
			// Connect to the remote device through the socket. This call blocks
			// until it succeeds or throws an exception.

			socket.connect()
			println("socket.connect()")
			var connectedThread=ConnectedThread(socket)
			connectedThread.start()
			sendBtn.setOnClickListener{
				connectedThread.write("123".toByteArray())
			}

			// The connection attempt succeeded. Perform work associated with
			// the connection in a separate thread.
//                manageMyConnectedSocket(socket)
		}
	}

	// Closes the client socket and causes the thread to finish.
	fun cancel() {
		try {
			mmSocket?.close()
		} catch (e: IOException) {
			println("Could not close the client socket")
		}
	}
}
private inner class ConnectedThread(var mmSocket: BluetoothSocket) : Thread() {
	private val mmInStream: InputStream?
	private val mmOutStream: OutputStream?
	override fun run() {
		val buffer = ByteArray(1024) // buffer store for the stream
		var bytes: Int // bytes returned from read()

		// Keep listening to the InputStream until an exception occurs
		while (true) {

			try {
				bytes = mmInStream!!.read(buffer)
				val readMessage = String(buffer, 0, bytes)
				println(readMessage)

			} catch (e: IOException) {
				break
			}
		}
	}

	/* Call this from the main activity to send data to the remote device */
	fun write(bytes: ByteArray?) {
		try {
			mmOutStream?.write(bytes)
		} catch (e: IOException) {
		}
	}

	/* Call this from the main activity to shutdown the connection */
	fun cancel() {
		try {
			mmSocket.close()
		} catch (e: IOException) {
		}
	}

	init {
		var tmpIn: InputStream? = null
		var tmpOut: OutputStream? = null

		// Get the input and output streams, using temp objects because
		// member streams are final
		try {
			tmpIn = mmSocket.inputStream
			tmpOut = mmSocket.outputStream
		} catch (e: IOException) {
		}
		mmInStream = tmpIn
		mmOutStream = tmpOut
	}
}

权限

<!--    Permission-->
<uses-permission
	android:name="android.permission.BLUETOOTH"
	tools:remove="android:maxSdkVersion" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />

<uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />

<uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />