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How to use Android Bluetooth 2.0

1.Android operation Bluetooth 2.0 use process

(1) find the device uuid
(2) obtain the Bluetooth adapter, make Bluetooth in the discoverable mode, acquire the socket of the lower computer, and establish a connection with the upper computer,
Obtain the input stream and output stream. If neither stream is empty, the connection is successful. Otherwise, the connection fails.
(3) start communication with the socket of the lower computer.

(4) after communication, disconnect (close flow and socket)

2 next, connect to the code directly:

2.1 find the UUID of the device (usually provided by the manufacturer to the developer)

UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

2.2 establish connection with Bluetooth device

        BluetoothAdapter myBluetoothAdapter = null;//Bluetooth adapter
	BluetoothServerSocket mBThServer = null;//Upper computer < span style = "font family: Arial, Helvetica, sans serif;" > ServerSocket</span>
	BluetoothSocket mBTHSocket = null;//socket of lower computer
	InputStream mmInStream = null;//Input stream
	OutputStream mmOutStream = null;//Output stream
 <span style="font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">        </span>

       myBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();//Get adapter
				Set<BluetoothDevice> pairedDevices = myBluetoothAdapter
						.getBondedDevices();//Get all Bluetooth devices under the adapter
				if (pairedDevices.size() > 0) {
					for (Iterator<BluetoothDevice> iterator = pairedDevices
							.iterator(); iterator.hasNext();) {
						BluetoothDevice device = (BluetoothDevice) iterator
								.next();
						if (DEVICE_NAME1.equals(device.getName())
								|| DEVICE_NAME2.equals(device.getName())
								|| DEVICE_NAME3.equals(device.getName())
								|| DEVICE_NAME4.equals(device.getName())) {
							try {
								myBluetoothAdapter.enable();//Make adapter settings available
								Intent discoverableIntent = new Intent(
										BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);// Make Bluetooth in discoverable mode for 150s
								discoverableIntent
										.putExtra(
												BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION,
												150);
								mBTHSocket = device
										.createRfcommSocketToServiceRecord(MY_UUID);//Get the socket of the lower computer

								int sdk = Integer.parseInt(Build.VERSION.SDK);
								if (sdk >= 10) {
									mBTHSocket = device
											.createInsecureRfcommSocketToServiceRecord(MY_UUID);
								} else {
									mBTHSocket = device
											.createRfcommSocketToServiceRecord(MY_UUID);
								}

								mBThServer = myBluetoothAdapter
										.listenUsingRfcommWithServiceRecord(
												"myServerSocket", MY_UUID);Monitor available devices
								mBTHSocket.connect(); // Establish connection
								mmInStream = mBTHSocket.getInputStream();// Get input stream
								mmOutStream = mBTHSocket.getOutputStream();// Get output stream

							} catch (IOException e) {
								ett.setText("Device connection is abnormal!");
							}
							if ((mmInStream != null) && (mmInStream != null))// If they are not empty, the connection is successful, otherwise, the connection fails
							{
								ett.setText("Device connected successfully!");
							} else {
								ett.setText("Device connection failed!");
							}
							break;
						}
					}
				}
			}

2.3 start sending data and read data (byte array)

                        if ((mmInStream == null) || (mmInStream == null)) {
				Readflage = -2;// Connection exception
				return;
			}
			mmOutStream.write(cmd_find);//Write find instruction
			Thread.sleep(200);
			int datalen = mmInStream.read(recData);//Read data

Note: both CMD find and recData are byte arrays byte []

The above code is the step of sending instructions and reading data at one time. Very simple.

2.4 disconnection

                                      if ((mmInStream == null) || (mmInStream == null)) {
						return;
					}
					//Turn off streams and socket s
					mmOutStream.close();
					mmInStream.close();
					mBTHSocket.close();
					mBThServer.close();

Finally, there are three basic steps, the first is to establish a connection, the second is to send data to read data, and the third is to disconnect. That's all for today. I will write about the use of Bluetooth 4.0 ble in Android later. There are still many differences between the two. Please look forward to it