问题
I connect bluetooth barcode scanner to my android tablet. barcode scanner is bonded with android device as a input device - HID profile. it shows as keyboard or mouse in system bluetooth manager. i discovered that bluetooth profile input device class exist but is hidden. class and btprofile constants have @hide annotaions in android docs.
hidden class:
http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.3.1_r1/android/bluetooth/BluetoothInputDevice.java
here they should be also 3 other constants
developer.android.com/reference/android/bluetooth/BluetoothProfile.html#HEADSET
just like
public static final int INPUT_DEVICE = 4;
public static final int PAN = 5;
public static final int PBAP = 6;
that constants are simple accessible by reflection. What i need to achieve, is list of devices by hid profile(INPUT_DEVICE). it should be simple with small changes using method:
developer.android.com/reference/android/bluetooth/BluetoothA2dp.html#getConnectedDevices()
not for A2dp profile, but for hid profile accessed also by reflection methods. sadly
Class c = Class.forName("android.bluetooth.BluetoothInputDevice")
won't work.. any ideas how i should approach to the problem ? i need only list of hid devices
回答1:
I figured out how to solve my problem. That was very helpful. First of all I needed to prepare reflection method which return input_device hidden constants of hid profile:
public static int getInputDeviceHiddenConstant() {
Class<BluetoothProfile> clazz = BluetoothProfile.class;
for (Field f : clazz.getFields()) {
int mod = f.getModifiers();
if (Modifier.isStatic(mod) && Modifier.isPublic(mod) && Modifier.isFinal(mod)) {
try {
if (f.getName().equals("INPUT_DEVICE")) {
return f.getInt(null);
}
} catch (Exception e) {
Log.e(LOG_TAG, e.toString(), e);
}
}
}
return -1;
}
Instead of that function, I could use value 4, but i want to do it elegant.
Second step was to define listener of specific profile:
BluetoothProfile.ServiceListener mProfileListener = new BluetoothProfile.ServiceListener() {
@Override
public void onServiceConnected(int profile, BluetoothProfile proxy) {
Log.i("btclass", profile + "");
if (profile == ConnectToLastBluetoothBarcodeDeviceTask.getInputDeviceHiddenConstans()) {
List<BluetoothDevice> connectedDevices = proxy.getConnectedDevices();
if (connectedDevices.size() == 0) {
} else if (connectedDevices.size() == 1) {
BluetoothDevice bluetoothDevice = connectedDevices.get(0);
...
} else {
Log.i("btclass", "too many input devices");
}
}
}
@Override
public void onServiceDisconnected(int profile) {
}
};
In third step I invoked
mBluetoothAdapter.getProfileProxy(getActivity(), mProfileListener,
ConnectToLastBluetoothBarcodeDeviceTask.getInputDeviceHiddenConstant());
Everything clearly works and mProfileListener returns me list of specific profile bluetooth device/-es. Most interesting thing takes place in onServiceConnected() method, which returs object of hidden class BluetoothInputDevice :)
来源:https://stackoverflow.com/questions/26341718/connection-to-specific-hid-profile-bluetooth-device