10分钟完成一个最最简单的BLE蓝牙接收数据的DEMO
- 2019 年 10 月 7 日
- 筆記
这两天在研究蓝牙，网上有关蓝牙的内容非常有限，Github上的蓝牙框架也很少很复杂，为此我特地写了一个最最简单的DEMO，实现BLE蓝牙接收数据的问题，
不需要什么特定的UUID，
不需要什么断开重连，
不需要什么多连接等等，
网上都把BLE蓝牙写的好复杂好复杂，那不是我想要的，我只想为新手提供一个最基本的例子
注意：
1.本DEMO运行前提是蓝牙已经配对成功，如果想实现自动配对可以期待我的下一篇文章
2.修改代码中的“你想要接收数据的已配对设备名称”为你真实的蓝牙设备
3.复制粘贴下面的代码，日志TAG是“BLE”
代码：
<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(); } //打开蓝牙 private void openBlueToothLe() { adapter = BluetoothAdapter.getDefaultAdapter(); if (null == adapter) { Toast.makeText(this, "没有蓝牙功能", Toast.LENGTH_SHORT).show(); return; } if (!adapter.isEnabled()) { adapter.enable(); } startScan(); } //开始扫描 private void startScan() { Set<BluetoothDevice> bondedDevices = adapter.getBondedDevices(); for (BluetoothDevice bondedDevice : bondedDevices) { if ("你想要接收数据的已配对设备名称".equals(bondedDevice.getName().trim())) { connectDevice(bondedDevice); } } } //连接设备 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) { // 来源：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; }}
对，就是这么简单，一个类足以，接下来就可以在Android studio的Logcat看到打印的返回值了
Github地址：https://github.com/king1039/BlueToothLe
