帮我写一个蓝牙连接并能接收数据的APP

好的，下面是一个简单的蓝牙连接并能接收数据的APP的实现步骤：

1. 在AndroidManifest.xml文件中添加以下权限：

<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

2. 在布局文件中添加一个按钮，用于连接蓝牙：

<Button
    android:id="@+id/btn_connect"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Connect"/>

3. 在Activity中实现蓝牙连接和数据接收的逻辑：

public class MainActivity extends AppCompatActivity {

    private BluetoothAdapter mBluetoothAdapter;
    private BluetoothSocket mBluetoothSocket;
    private InputStream mInputStream;
    private Button mBtnConnect;

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

        mBtnConnect = findViewById(R.id.btn_connect);
        mBtnConnect.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                connectBluetooth();
            }
        });

        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        if (mBluetoothAdapter == null) {
            Toast.makeText(this, "Device does not support Bluetooth", Toast.LENGTH_SHORT).show();
            finish();
            return;
        }

        if (!mBluetoothAdapter.isEnabled()) {
            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
        }
    }

    private void connectBluetooth() {
        Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
        if (pairedDevices.size() > 0) {
            for (BluetoothDevice device : pairedDevices) {
                if (device.getName().equals("Your Bluetooth Device Name")) {
                    try {
                        mBluetoothSocket = device.createRfcommSocketToServiceRecord(UUID.fromString("Your UUID"));
                        mBluetoothSocket.connect();
                        mInputStream = mBluetoothSocket.getInputStream();
                        startListening();
                        Toast.makeText(this, "Bluetooth connected", Toast.LENGTH_SHORT).show();
                    } catch (IOException e) {
                        Toast.makeText(this, "Failed to connect Bluetooth", Toast.LENGTH_SHORT).show();
                        e.printStackTrace();
                    }
                    break;
                }
            }
        } else {
            Toast.makeText(this, "No paired Bluetooth devices found", Toast.LENGTH_SHORT).show();
        }
    }

    private void startListening() {
        new Thread(new Runnable() {
            @Override
            public void run() {
                byte[] buffer = new byte[1024];
                int bytes;
                while (true) {
                    try {
                        bytes = mInputStream.read(buffer);
                        final String message = new String(buffer, 0, bytes);
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                // Handle received message here
                            }
                        });
                    } catch (IOException e) {
                        break;
                    }
                }
            }
        }).start();
    }
}

在上面的代码中，connectBluetooth()方法用于连接蓝牙设备，startListening()方法用于启动一个新的线程来监听蓝牙设备发送的数据。你需要将"Your Bluetooth Device Name"和"Your UUID"替换为你所连接的蓝牙设备的名称和UUID。

希望这个简单的示例可以帮到你！