guizero Raspberry Pi:按钮->命令序列问题

Question

要求:按下guizero上的一个按钮，首先设置一个文本值，然后执行一个函数(这里是一个简单的time.sleep()；最初是一个子进程)；在执行该函数之后，应该显示一个结果文本；

#!/usr/bin/python3
# -*- coding: utf-8 -*-

from guizero import App, PushButton, Text
import subprocess
import time

# Action you would like to perform
def counter0():
    global s0
    text0.value = int(text0.value) + 1  # works
    text1.value = s0                    # works

def counter1():
    global s0
    text1.value = s0       # display a status value - but does not (!)
    time.sleep(1)          # originally a subprocess is called here; works
    text1.value = "ready"  # only diplays this after a delay

s0="start something after pressing butt1"

app = App("Hello world", layout="grid")

text0 = Text(app, text="1", align="left", grid=[0,1])
text1 = Text(app, text=s0, align="left",grid=[0,8] )
butt1 = PushButton(app, text="Button", command=counter1, align="left", grid=[0,2])
text0.repeat(10000, counter0)  # Schedule call to counter() every 1000ms

app.display()

很可能我不明白吉泽罗背后的想法。对如何管理这些需求有什么想法吗？

Answer 1

如果我正确理解你的问题，你的具体问题是：

    text1.value = s0       # display a status value - but does not (!)

这不起作用，因为guizero框架同步执行函数:在函数返回之前，不执行其他代码(包括更新显示的代码)。

如果你想：

在使用subprocess

• Run运行命令之前
• 显示消息--在命令完成

之后

然后，您将需要重写您的逻辑，这样您的应用程序就不会等待“抗衡1”完成。异步运行代码的一个选项是在一个单独的线程中运行它。例如：

from guizero import App, PushButton, Text
import threading
import time


# Action you would like to perform
def counter0():
    global s0
    text0.value = int(text0.value) + 1  # works
    text1.value = s0                    # works


def run_command():
    time.sleep(1)          # originally a subprocess is called here; works
    text1.value = "ready"  # only diplays this after a delay


def counter1():
    global s0
    text1.value = "Running command..."
    threading.Thread(target=run_command).start()


s0 = "start something after pressing butt1"

app = App("Hello world", layout="grid")

text0 = Text(app, text="1", align="left", grid=[0, 1])
text1 = Text(app, text=s0, align="left", grid=[0, 8])
butt1 = PushButton(app, text="Button", command=counter1,
                   align="left", grid=[0, 2])
text0.repeat(10000, counter0)

app.display()

运行上述代码将为您提供以下行为：

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