10分鐘完成一個最最簡單的BLE藍牙接收數據的DEMO
- 2019 年 10 月 7 日
- 筆記
這兩天在研究藍牙，網上有關藍牙的內容非常有限，Github上的藍牙框架也很少很複雜，為此我特地寫了一個最最簡單的DEMO，實現BLE藍牙接收數據的問題，
不需要什麼特定的UUID，
不需要什麼斷開重連，
不需要什麼多連接等等，
網上都把BLE藍牙寫的好複雜好複雜，那不是我想要的，我只想為新手提供一個最基本的例子
注意：
1.本DEMO運行前提是藍牙已經配對成功，如果想實現自動配對可以期待我的下一篇文章
2.修改程式碼中的「你想要接收數據的已配對設備名稱」為你真實的藍牙設備
3.複製粘貼下面的程式碼，日誌TAG是「BLE」
程式碼：
<uses-permission android:name="android.permission.BLUETOOTH" /><uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
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.BluetoothGattService;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.widget.Toast; import java.util.List;import java.util.Set;import java.util.UUID; public class MainActivity extends AppCompatActivity { private BluetoothAdapter adapter; private BluetoothGatt bluetoothGatt; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); openBlueToothLe(); } //打開藍牙 private void openBlueToothLe() { adapter = BluetoothAdapter.getDefaultAdapter(); if (null == adapter) { Toast.makeText(this, "沒有藍牙功能", Toast.LENGTH_SHORT).show(); return; } if (!adapter.isEnabled()) { adapter.enable(); } startScan(); } //開始掃描 private void startScan() { Set<BluetoothDevice> bondedDevices = adapter.getBondedDevices(); for (BluetoothDevice bondedDevice : bondedDevices) { if ("你想要接收數據的已配對設備名稱".equals(bondedDevice.getName().trim())) { connectDevice(bondedDevice); } } } //連接設備 private void connectDevice(BluetoothDevice bondedDevice) { bluetoothGatt = bondedDevice.connectGatt(this, false, new BluetoothGattCallback() { @Override public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) { super.onConnectionStateChange(gatt, status, newState); if (BluetoothGatt.STATE_CONNECTED == newState) { bluetoothGatt = gatt; gatt.discoverServices(); } else if (BluetoothGatt.STATE_DISCONNECTED == newState) { gatt.close(); } } @Override public void onServicesDiscovered(BluetoothGatt gatt, int status) { super.onServicesDiscovered(gatt, status); List<BluetoothGattService> services = gatt.getServices(); for (BluetoothGattService service : services) { List<BluetoothGattCharacteristic> characteristics = service.getCharacteristics(); for (BluetoothGattCharacteristic character : characteristics) { enableNotification(gatt, service.getUuid(), character.getUuid()); } } } @Override public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) { super.onCharacteristicChanged(gatt, characteristic); byte[] value = characteristic.getValue(); Log.i("BLE", "receive value ----------------------------"); for (int i = 0; i < value.length; i++) { Log.i("BLE", "character_value = " + value[i]); } } }); } @Override protected void onDestroy() { super.onDestroy(); bluetoothGatt.disconnect(); } public boolean enableNotification(BluetoothGatt gatt, UUID serviceUUID, UUID characteristicUUID) { boolean success = false; BluetoothGattService service = gatt.getService(serviceUUID); if (service != null) { BluetoothGattCharacteristic characteristic = findNotifyCharacteristic(service, characteristicUUID); if (characteristic != null) { success = gatt.setCharacteristicNotification(characteristic, true); if (success) { // 來源：http://stackoverflow.com/questions/38045294/oncharacteristicchanged-not-called-with-ble for (BluetoothGattDescriptor dp : characteristic.getDescriptors()) { if (dp != null) { if ((characteristic.getProperties() & BluetoothGattCharacteristic.PROPERTY_NOTIFY) != 0) { dp.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE); } else if ((characteristic.getProperties() & BluetoothGattCharacteristic.PROPERTY_INDICATE) != 0) { dp.setValue(BluetoothGattDescriptor.ENABLE_INDICATION_VALUE); } gatt.writeDescriptor(dp); } } } } } return success; } private BluetoothGattCharacteristic findNotifyCharacteristic(BluetoothGattService service, UUID characteristicUUID) { BluetoothGattCharacteristic characteristic = null; List<BluetoothGattCharacteristic> characteristics = service.getCharacteristics(); for (BluetoothGattCharacteristic c : characteristics) { if ((c.getProperties() & BluetoothGattCharacteristic.PROPERTY_NOTIFY) != 0 && characteristicUUID.equals(c.getUuid())) { characteristic = c; break; } } if (characteristic != null) return characteristic; for (BluetoothGattCharacteristic c : characteristics) { if ((c.getProperties() & BluetoothGattCharacteristic.PROPERTY_INDICATE) != 0 && characteristicUUID.equals(c.getUuid())) { characteristic = c; break; } } return characteristic; }}
對，就是這麼簡單，一個類足以，接下來就可以在Android studio的Logcat看到列印的返回值了
Github地址：https://github.com/king1039/BlueToothLe
