PyQt5 – 数字秒表

在本文中，我们将了解如何使用Python GUI – PyQt5 创建秒表。
秒表是一种手持式时计，旨在测量其激活和停用之间经过的时间。为远距离观看而设计的大型数字版秒表，例如在体育场内，称为秒表。

Steps to create a stop watch –

1. Create a counter which signify the seconds
2. Create flag to know when to start and when to pause, set it to False
3. Create label to show seconds
4. Create three push button for starting the stop watch pausing the stop watch and for re-setting the stop watch
5. Add action to each push button.
6. Inside start push button action make flag to true
7. Inside pause push button action make flag to false
8. Inside reset push button action make flag to false and make the counter value to 0
9. Create QTimer object which calls a method after every 100 millisecond i.e 10th part of second
10. Inside QTimer object method check for the flag status if it is true increment the counter
11. Show the counter value through label using setText method.

下面是实现——

# importing libraries
from PyQt5.QtWidgets import * 
from PyQt5 import QtCore, QtGui
from PyQt5.QtGui import * 
from PyQt5.QtCore import * 
import sys
  
  
class Window(QMainWindow):
  
    def __init__(self):
        super().__init__()
  
        # setting title
        self.setWindowTitle("Python Stop watch")
  
        # setting geometry
        self.setGeometry(100, 100, 400, 500)
  
        # calling method
        self.UiComponents()
  
        # showing all the widgets
        self.show()
  
    # method for widgets
    def UiComponents(self):
  
        # counter
        self.count = 0
  
        # creating flag
        self.flag = False
  
        # creating a label to show the time
        self.label = QLabel(self)
  
        # setting geometry of label
        self.label.setGeometry(75, 100, 250, 70)
  
        # adding border to the label
        self.label.setStyleSheet("border : 4px solid black;")
  
        # setting text to the label
        self.label.setText(str(self.count))
  
        # setting font to the label
        self.label.setFont(QFont('Arial', 25))
  
        # setting alignment to the text of label
        self.label.setAlignment(Qt.AlignCenter)
  
        # creating start button
        start = QPushButton("Start", self)
  
        # setting geometry to the button
        start.setGeometry(125, 250, 150, 40)
  
        # add action to the method
        start.pressed.connect(self.Start)
  
        # creating pause button
        pause = QPushButton("Pause", self)
  
        # setting geometry to the button
        pause.setGeometry(125, 300, 150, 40)
  
        # add action to the method
        pause.pressed.connect(self.Pause)
  
        # creating reset button
        re_set = QPushButton("Re-set", self)
  
        # setting geometry to the button
        re_set.setGeometry(125, 350, 150, 40)
  
        # add action to the method
        re_set.pressed.connect(self.Re_set)
  
        # creating a timer object
        timer = QTimer(self)
  
        # adding action to timer
        timer.timeout.connect(self.showTime)
  
        # update the timer every tenth second
        timer.start(100)
  
    # method called by timer
    def showTime(self):
  
        # checking if flag is true
        if self.flag:
  
            # incrementing the counter
            self.count+= 1
  
        # getting text from count
        text = str(self.count / 10)
  
        # showing text
        self.label.setText(text)
  
  
    def Start(self):
  
        # making flag to true
        self.flag = True
  
    def Pause(self):
  
        # making flag to False
        self.flag = False
  
    def Re_set(self):
  
        # making flag to false
        self.flag = False
  
        # reseeting the count
        self.count = 0
  
        # setting text to label
        self.label.setText(str(self.count))
  
  
# create pyqt5 app
App = QApplication(sys.argv)
  
# create the instance of our Window
window = Window()
  
# start the app
sys.exit(App.exec())

输出 ：