如何在ThingsBoard的控件小部件中使用getValue方法

Question

使用Control窗口小部件开关时，我可以从事物板上设置按钮值（setValue方法）到我的设备，但是我无法弄清楚如何在事物板上获得按钮值（getValue方法）。 我已经尝试过此代码，但是按钮未获取值。请帮我解决这个问题。

button_state = {'value': False}

def setValue (params):
    button_state['data'] = params
    print("setValue set to : ",button_state)

def on_connect(client, userdata, flags, rc):
    print("rc code:",rc)
    client.subscribe('v1/devices/me/rpc/request/+')

def on_message(client, userdata, msg):
    print('Topic: ' + msg.topic + '\nMessage: ' + str(msg.payload))
    if msg.topic.startswith('v1/devices/me/rpc/request/'):
        requestId = msg.topic[len('v1/devices/me/rpc/request/'):len(msg.topic)]
        print("requestId : ",requestId)
        data = json.loads(msg.payload)
        if data['method'] == 'getValue':
            print("getvalue request\n")
            print("sended getValue: ",button_state)
            client.publish('v1/devices/me/rpc/response/'+requestId, json.dumps(button_state), 1)
        if data['method'] == 'setValue':
            print("setvalue request\n")
            params = data['params']
            setValue(params)
            client.publish('v1/devices/me/attributes', json.dumps(button_state), 1)