解决方案

Question

我想要实现的目标：当屏幕从ScreenOne切换到ScreenTwo时，运行一个＆＃39; while循环＆＃39;功能，直到按下ScreenTwo上的按钮并打破循环。

此功能应该从连接到我的计算机的条形码扫描仪运行和接收输入（含义，输入是条形码），并使用扫描的条形码数量更新ScreenTwo上的标签。

然后，一旦我没有更多条形码进行扫描，请按＆＃34;完成＆＃34; ScreenTwo上的按钮 - 应该发送输入＆＃34; 999＆＃34;打破循环功能。

我在屏幕切换时尝试运行功能的方法：使用＆＃39; on_enter＆＃39;

class ScreenTwo(Screen):
    def on_enter(self):
        getStatus()
        updatePoints()

我面临的问题：

屏幕从ScreenOne切换到ScreenTwo，功能运行（我看到它发生在Mac终端上） BUT ScreenTwo上的按钮无法按下（Mac色轮旋转）
我还没弄明白如何完成＆＃34;完成＆＃34;按钮发送输入＆＃39; 999＆＃39;打破循环的功能。

如何解决1？

如何实现2？

以下分别是ScreenOne和ScreenTwo的截图：

这里是returnStation2.py文件

from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.properties import ObjectProperty


def getStatus():
    while True:
        answer = input('What is the box ID? ')
        if answer == 999: #LOOPS BREAK WHEN INPUT IS 999
            break
        elif type(answer) == int:
            do something
        else:
            print('Sorry I did not get that')

def updatePoints():
    do something

class ScreenManagement(ScreenManager):
    screen_one = ObjectProperty(None)
    screen_two = ObjectProperty(None)

class ScreenOne(Screen):
    member_status = ObjectProperty(None)

    def backspace(self, textString):
        newTextString = textString[0:-1]
        self.display.text = newTextString

    def getPoints(self, phoneNumber):
        self.manager.screen_two.member_status.text = phoneNumber

class ScreenTwo(Screen):
    input_text = ObjectProperty(None)

    def on_enter(self):
        getStatus()
        updatePoints()

    def clearField(self):
        self.manager.screen_one.input_text.text = ""

class ReturnStationLayout2App(App):

    def build(self):
        return ScreenManagement()


if __name__ == '__main__':
    ReturnStationLayout2App().run()

这是returnStationLayout2.kv

＆＃34;完成＆＃34;按钮（在ScreenTwo中）位于脚本的底部。

当屏幕切换到ScreenTwo时，无法按下它。我希望在按下时，它可以输入＆＃9; 999＆＃39;打破正在运行的循环函数。

<ScreenManagement>:
    screen_one: screen_one
    screen_two: screen_two

    ScreenOne:
        id: screen_one
        name: 'menu'
    ScreenTwo:
        id: screen_two
        name: 'settings'

<CustButton@Button>:
    font_size: 32

<ScreenOne>:
    input_text : entry
    GridLayout:
        id: numberPad
        rows: 5
        padding: [300,200]
        spacing: 10

        # Where input is displayed
        BoxLayout:
            Label:
                text: "+65"
                font_size: 50
                size_hint: 0.2, 1
            TextInput:
                id: entry
                font_size: 50
                multiline: False
                padding: [20, ( self.height - self.line_height ) / 2]


        BoxLayout:
            spacing: 10
            CustButton:
                text: "1"
                on_press: entry.text += self.text
            CustButton:
                text: "2"
                on_press: entry.text += self.text
            CustButton:
                text: "3"
                on_press: entry.text += self.text
            CustButton:
                text: "DEL"
                on_press: root.backspace(entry.text)

        BoxLayout:
            spacing: 10
            CustButton:
                text: "4"
                on_press: entry.text += self.text
            CustButton:
                text: "5"
                on_press: entry.text += self.text
            CustButton:
                text: "6"
                on_press: entry.text += self.text
            CustButton:
                text: "AC"
                on_press: entry.text = ""

        BoxLayout:
            spacing: 10
            CustButton:
                text: "7"
                on_press: entry.text += self.text
            CustButton:
                text: "8"
                on_press: entry.text += self.text
            CustButton:
                text: "9"
                on_press: entry.text += self.text
            CustButton:
                text: "Enter" #HERE IS THE ENTER BUTTON
                on_press:
                    root.manager.transition.direction = 'left'
                    root.manager.transition.duration = 1
                    root.manager.current = 'settings'
                    root.getPoints(entry.text)

        BoxLayout:
            spacing: 10
            Label:
                text: ""
            CustButton:
                text: "0"
                on_press: entry.text += self.text
            Label:
                text: ""
            Label:
                text: ""

<ScreenTwo>:
    member_status: memberStatus
    BoxLayout:
        Label:
            id: memberStatus
            text: ''  
        GridLayout:
            rows: 3
            padding: [100,500]
            spacing: 10
            BoxLayout:
                Label:
                    text: "You have scanned:"
            BoxLayout:
                CustButton:
                    text: "Done" #THIS IS THE BUTTON I HOPE TO BE ABLE TO BREAK THE LOOP FUNCTION
                    on_press:
                        root.manager.transition.direction = "right"
                        root.manager.current = 'menu'
                        root.clearField()

Answer 1

解决方案

此答案基于问题中的评论部分中的讨论。下面的代码是在扫描条形码时扫描器发送特定信号的假设下编写的。总体思路是在发送信号后运行一个函数。

时钟周期

我建议熟悉kivy的Clock对象。可以创建一个侦听器函数来检查信号是否每n秒发送一次。确切地说，让我们说你想在检测到信号后运行process()功能。如果成功扫描条形码并创建一个监听器来检查信号是否已发送，那么我们还会声明一个变量scanned来存储信息（因此请检查scanned变量是否成立{{1} }）。以下代码示例将True变量每隔2秒设置为scanned以模拟扫描行为。

True

输出：

from kivy.app import App
from kivy.clock import Clock
from kivy.uix.button import Button
from kivy.uix.screenmanager import Screen

# Define constants and the scanned variable, for easy example
INTERVAL = 0.01
scanned = False


# Process method runs every 0.01 seconds, note the use of dt argument (explained in docs)
def process(dt):
    # Retrieve the global variable, for easy example
    global scanned

    # Check if scanned, note setting scanned to False once an item was scanned.
    # Here you can also check the uniqueness of the scanned barcode (to avoid having the same barcode processed many times)
    if scanned is True:
        print("Scanned! Processing the data and setting scanned to False.")
        scanned = False
    else:
        print("Not scanned yet!")


# Mimic scanning behaviour
def scan(dt):
    # Retrieve the global variable and set it to true 
    global scanned
    scanned = True


class Main(App):

    def __init__(self):
        super(Main, self).__init__()

        # Schedule the functions to be called every n seconds
        Clock.schedule_interval(process, INTERVAL)
        Clock.schedule_interval(scan, INTERVAL*200)

    def build(self):
        # Display screen with a single button for easy example
        scr = Screen()
        btn = Button(text="You can press me but nothing will happen!")
        scr.add_widget(btn)
        return scr


if __name__ == '__main__':
    Main().run()

kivy：屏幕切换时如何在没有挂屏的情况下运行循环功能？

1 个答案:

解决方案

时钟周期