在Android中以编程方式连接蓝牙设备，无需用户交互

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import java.io.IOException;
import java.util.UUID;

public class MainActivity extends AppCompatActivity {

    private static final int REQUEST_ENABLE_BT = 1;
    private static final String DEVICE_ADDRESS = "00:00:00:00:00:00"; // 蓝牙设备的MAC地址
    private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); // SPP蓝牙服务的UUID

    private BluetoothAdapter bluetoothAdapter;
    private BluetoothDevice bluetoothDevice;
    private BluetoothSocket bluetoothSocket;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        if (bluetoothAdapter == null) {
            // 设备不支持蓝牙
            Toast.makeText(this, "设备不支持蓝牙", Toast.LENGTH_SHORT).show();
            return;
        }

        if (!bluetoothAdapter.isEnabled()) {
            // 请求用户授权打开蓝牙
            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
        } else {
            connectBluetoothDevice();
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_ENABLE_BT) {
            if (resultCode == RESULT_OK) {
                // 用户已授权打开蓝牙
                connectBluetoothDevice();
            } else {
                // 用户未授权打开蓝牙
                Toast.makeText(this, "用户未授权打开蓝牙", Toast.LENGTH_SHORT).show();
            }
        }
    }

    private void connectBluetoothDevice() {
        bluetoothDevice = bluetoothAdapter.getRemoteDevice(DEVICE_ADDRESS);
        try {
            bluetoothSocket = bluetoothDevice.createRfcommSocketToServiceRecord(MY_UUID);
            bluetoothSocket.connect();
            // 连接成功，可以进行数据传输
            Toast.makeText(this, "蓝牙设备连接成功", Toast.LENGTH_SHORT).show();
        } catch (IOException e) {
            // 连接失败
            Toast.makeText(this, "蓝牙设备连接失败", Toast.LENGTH_SHORT).show();
            e.printStackTrace();
        }
    }
}