我正在创建一个使用 BLE 与 MCU 通信的 Android 应用程序，目前我可以使用我的应用程序连接到 MCU，但是当我尝试发现并获取设备的服务时，我返回了一个空数组，并且不确定原因。
//Code used to connect to the device
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState){
String intentAction;
if (newState == BluetoothProfile.STATE_CONNECTED) {
intentAction = ACTION_GATT_CONNECTED;
mConnectionState = STATE_CONNECTED;
broadcastUpdate(intentAction);
Log.i("TAG", "Connected to GATT server.");
// Attempts to discover services after successful connection.
Log.i("TAG", "Attempting to start service discovery:" + mGatt.discoverServices());
services = mGatt.getServices();
System.out.println("Service 1 is : " + services.get(0));
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
intentAction = ACTION_GATT_DISCONNECTED;
mConnectionState = STATE_DISCONNECTED;
Log.i("TAG", "Disconnected from GATT server.");
broadcastUpdate(intentAction);
}
}
输出:
09-26 16:33:09.648 10917-10931/bamboomobile.medhead I/TAG: Connected to GATT server.
09-26 16:33:09.648 10917-10931/bamboomobile.medhead D/BluetoothGatt: discoverServices() - device: DC:1B:A3:10:B9:D5
09-26 16:33:09.658 10917-10931/bamboomobile.medhead I/TAG: Attempting to start service discovery:true
09-26 16:33:09.668 10917-10931/bamboomobile.medhead W/BluetoothGatt: Unhandled exception in callback java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0 at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255) at java.util.ArrayList.get(ArrayList.java:308) at bamboomobile.medhead.MainMenu$1.onConnectionStateChange(MainMenu.java:86) at android.bluetooth.BluetoothGatt$1.onClientConnectionState(BluetoothGatt.java:186) at android.bluetooth.IBluetoothGattCallback$Stub.onTransact(IBluetoothGattCallback.java:70) at android.os.Binder.execTransact(Binder.java:446)
09-26 16:33:09.688 10917-10931/bamboomobile.medhead D/BluetoothGatt: onSearchComplete() = Device=DC:1B:A3:10:B9:D5 Status=0
最佳答案
连接后，您需要调用mGatt.discoverServices()。然后在 onServicesDiscovered 回调中，您可以使用 mGatt.getServices() 并继续。
关于Java BLE 不返回服务，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/39711973/