這是我的代碼import paho.mqtt.client as mqttimport jsonfrom tkinter import *from tkmacosx import *class App:    def __init__(self, master):        frame = Frame(master)        frame.pack()        self.button = Button(frame, text="QUIT", fg="red", command=frame.quit)        self.button.pack(side=LEFT)        self.hi_there = Button(frame, text="Hello", command=self.say_hi)        self.hi_there.pack(side=LEFT)    def say_hi(self):        print("hi there, everyone!")def on_connect(client, userdata, flags, rc):    print("Connected with result code "+str(rc))    client.subscribe("$SYS/broker/clients/connected")def on_message(client, userdata, msg):    data = json.loads(msg.payload)    print(data)root = Tk()client = mqtt.Client()app = App(root)root.mainloop()client.on_connect = on_connectclient.on_message = on_messageclient.connect("test.mosquitto.org", 1883, 60)client.loop_forever()不要太擔(dān)心它現(xiàn)在做了什么。我需要了解的是無(wú)限循環(huán)的概念。我需要一個(gè)無(wú)限循環(huán)來(lái)將 tkinter 窗口保持在屏幕上。我還需要一個(gè)無(wú)限循環(huán)來(lái)保持 MQTT 客戶端連接處于活動(dòng)狀態(tài)。我如何在我的代碼中定位那些無(wú)限循環(huán)？如果我將 root.mainloop() 放在 client.loopforever() 之前，我只會(huì)在關(guān)閉 tkinter 窗口時(shí)訪問(wèn) MQTT 代碼。如果我將 root.mainloop() 放在 client.loopforever() 之后，則當(dāng)我關(guān)閉 MQTT 連接時(shí)會(huì)顯示 tkinter 窗口。這個(gè)想法是從代理獲取消息并在 tkinter 窗口中顯示它們。請(qǐng)幫助我了解這兩個(gè)無(wú)限循環(huán)的位置。