Question

我想创建一个可以与蓝牙低功耗模块连接并可以接收数据的android应用。在我的系统中，微控制器stm32f1通过UART将测量数据发送到BT LE模块。

我的问题是如何开始？我对GATT和UART服务有很多了解，但仍然不知道如何开始。请给我一些信息。

Answer 1

You need:

UUIDs of your Service, Characteristic and Descriptor;
Permissions' Bluetooth Low Energy

The program must:

Scan BLE devices
Connect a device
Set callbacks' BLE

AndroidManifest.xml

<uses-feature android:name="android.hardware.bluetooth_le" android:required="true"/>
<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

Activity.java

// Bluetooth's variables
    BluetoothAdapter bluetoothAdapter;
    BluetoothLeScanner bluetoothLeScanner;
    BluetoothManager bluetoothManager;
    BluetoothScanCallback bluetoothScanCallback;
    BluetoothGatt gattClient;

    BluetoothGattCharacteristic characteristicID; // To get Value

// UUID's (set yours)
final UUID SERVICE_UUID = UUID.fromString("ab0828b1-198e-4351-b779-901fa0e0371e");
final UUID CHARACTERISTIC_UUID_ID = UUID.fromString("1a220d0a-6b06-4767-8692-243153d94d85");
final UUID DESCRIPTOR_UUID_ID = UUID.fromString("ec6e1003-884b-4a1c-850f-1cfce9cf6567");

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

    // Bluetooth
    bluetoothManager = (BluetoothManager) getSystemService(BLUETOOTH_SERVICE);
    bluetoothAdapter = bluetoothManager.getAdapter();
    startScan();
}

 // BLUETOOTH SCAN

private void startScan(){
    Log.i(TAG,"startScan()");
    bluetoothScanCallback = new BluetoothScanCallback();
    bluetoothLeScanner = bluetoothAdapter.getBluetoothLeScanner();
    bluetoothLeScanner.startScan(bluetoothScanCallback);
}

// BLUETOOTH CONNECTION
private void connectDevice(BluetoothDevice device) {
    if (device == null) Log.i(TAG,"Device is null");
    GattClientCallback gattClientCallback = new GattClientCallback();
    gattClient = device.connectGatt(this,false,gattClientCallback);
}

// BLE Scan Callbacks
private class BluetoothScanCallback extends ScanCallback {

    @Override
    public void onScanResult(int callbackType, ScanResult result) {
        Log.i(TAG, "onScanResult");
        if (result.getDevice().getName() != null){
            if (result.getDevice().getName().equals(YOUR_DEVICE_NAME)) {
                // When find your device, connect.
                connectDevice(result.getDevice());
                bluetoothLeScanner.stopScan(bluetoothScanCallback); // stop scan
            }
        }
    }

    @Override
    public void onBatchScanResults(List<ScanResult> results) {
        Log.i(TAG, "onBathScanResults");
    }

    @Override
    public void onScanFailed(int errorCode) {
        Log.i(TAG, "ErrorCode: " + errorCode);
    }            
}

// Bluetooth GATT Client Callback
private class GattClientCallback extends BluetoothGattCallback {
    @Override
    public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
        super.onConnectionStateChange(gatt, status, newState);
        Log.i(TAG,"onConnectionStateChange");

        if (status == BluetoothGatt.GATT_FAILURE) {
            Log.i(TAG, "onConnectionStateChange GATT FAILURE");
            return;
        } else if (status != BluetoothGatt.GATT_SUCCESS) {
            Log.i(TAG, "onConnectionStateChange != GATT_SUCCESS");
            return;
        }

        if (newState == BluetoothProfile.STATE_CONNECTED) {
            Log.i(TAG, "onConnectionStateChange CONNECTED");
            gatt.discoverServices();
        } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
            Log.i(TAG, "onConnectionStateChange DISCONNECTED");
        }
    }

    @Override
    public void onServicesDiscovered(BluetoothGatt gatt, int status) {
        super.onServicesDiscovered(gatt, status);
        Log.i(TAG,"onServicesDiscovered");
        if (status != BluetoothGatt.GATT_SUCCESS) return;

        // Reference your UUIDs
        characteristicID = gatt.getService(SERVICE_UUID).getCharacteristic(CHARACTERISTIC_UUID_ID);
        gatt.setCharacteristicNotification(characteristicID,true);

        BluetoothGattDescriptor descriptor = characteristicID.getDescriptor(DESCRIPTOR_UUID_ID);
        descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
        gatt.writeDescriptor(descriptor);
    }

    @Override
    public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
        super.onCharacteristicRead(gatt, characteristic, status);
        Log.i(TAG,"onCharacteristicRead");
    }

    @Override
    public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
        super.onCharacteristicWrite(gatt, characteristic, status);
        Log.i(TAG,"onCharacteristicWrite");
    }

    @Override
    public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
        super.onCharacteristicChanged(gatt, characteristic);
        Log.i(TAG,"onCharacteristicChanged");
        // Here you can read the characteristc's value
        // new String(characteristic.getValue();
    }

    @Override
    public void onDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) {
        super.onDescriptorRead(gatt, descriptor, status);
        Log.i(TAG,"onDescriptorRead");
    }

    @Override
    public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) {
        super.onDescriptorWrite(gatt, descriptor, status);
        Log.i(TAG,"onDescriptorWrite");
    }
}

Libs:

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattDescriptor;
import android.bluetooth.BluetoothManager;
import android.bluetooth.BluetoothProfile;
import android.bluetooth.le.BluetoothLeScanner;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanResult;

Notes:

The UUIDs must be same seted on the module.
In your program you must have two callbacks: ScanCallback and GattCallback. Scan callback is to manage the scan results and the GattCallback you can manage the data input/output.
This code the basic to show how use BLE on Android, works fine for me.
You can generate UUID here: https://www.uuidgenerator.net/

Android应用，通过UART通过单片机发送的BLE模块接收数据

1 个答案: