Question

I have a bluetooth device which has a single button to take a photo using connected android device.

In my application, I can control which device has been connected. But, I need more.

I just wonder that Is it possible to listen click of bluetooth device button from my android application? If it is, at that case, I can use this bluetooth device to my purpose.

Do I need some hack for my bluetooth device ?

Answer 1

您的蓝牙设备需要有一个 API 规范 - 它可以发送的信号列表。它可以像服务器或客户端一样工作，我们可以通过 BluetoothSocket 类连接到它并监听它的事件。 Here 对其进行了更详细的描述。

不过还有第二种选择。如果这是一些便宜的中国点击器，可以从远处拍摄照片，它将以相对简单的方式工作。通常，这些设备被识别为远程键盘。这意味着您可以覆盖 onKeyDown(int keyCode, KeyEvent event)/View 的 Activity 方法，检查从设备发送的 keyCode，并相应地处理它。

在第二种情况下，建立连接后，您不需要任何额外的蓝牙相关代码更改即可使其工作。

Answer 2

这取决于 BT 设备的通信方式。但是许多设备使用 Gatt 通信。因此，您可以执行以下操作来侦听事件：

        val btManager = view.getSystemService(BLUETOOTH_SERVICE) as BluetoothManager
        val connectedDevices = btManager.getConnectedDevices(GATT)

            connectedDevices.forEach {
                listen(it)
         }


private fun listen(dev: BluetoothDevice) {
    gatt_l = dev.connectGatt(view, false, object : BluetoothGattCallback() {

        override fun onConnectionStateChange(gatt: BluetoothGatt?, status: Int, newState: Int) {
                if (newState == BluetoothProfile.STATE_CONNECTED)
                       gatt?.discoverServices() //on connection, discover services of the BT device that it is offering.
                super.onConnectionStateChange(gatt, status, newState)
            }
            override fun onServicesDiscovered(gatt: BluetoothGatt?, status: Int) {
                super.onServicesDiscovered(gatt, status)
                gatt?.services?.forEach { service ->
                    if (service.uuid.toString() == DESIRED_SERVICE) // DESIRED_SERVICE that u r interested in. Initially u will have to go through every service to get ur event.
                      service.characteristics.forEach { // each service has characterstics, u need to listen to all of these to find ur event.
                        if (it.uuid.toString() == DESIRED_CHARAC_UUID) {
                            gatt.readCharacteristic(it)
                            gatt.setCharacteristicNotification(it, true)
                            return@forEach
                        }
                    }
                }
            }

            override fun onCharacteristicChanged(gatt: BluetoothGatt?, characteristic: BluetoothGattCharacteristic?) {
      //When the button on device is tapped, u should get the event here.
                characteristic?.value?.let { data ->
    //this "data" should be the event u want to listen. YOUR LOGIC.
                       }
                super.onCharacteristicChanged(gatt, characteristic)
            }
        }

        override fun onCharacteristicRead(gatt: BluetoothGatt?, characteristic: BluetoothGattCharacteristic?, status: Int) {
            super.onCharacteristicRead(gatt, characteristic, status)
        }
    }, BluetoothDevice.TRANSPORT_LE)
}

Listen button click of the connected bluetooth device from android application

2 个答案: