如何在Python中增加QLCDNumber

Question

我正在嘗試更新QLCDNumber的值。我想要做的是在一個單獨的線程中運行一個函數，輸出一個值（在這種情況下只需向上計數），並將該值顯示在屏幕上。

這裏是我使用的python腳本，再下面是的.ui文件（其中QLCDNumber被命名爲 「DISP」）的內容：

import sys 
import threading 
from PyQt4.QtCore import * 
from PyQt4.QtGui import * 
from PyQt4 import uic 
from time import sleep 


Ui_MainWindow, QtBaseClass = uic.loadUiType("./disp.ui") 

class MainWindow(QMainWindow, Ui_MainWindow): 
    counter = pyqtSignal(int) 
    counting = False 

    def __init__(self): 
     QMainWindow.__init__(self) 
     Ui_MainWindow.__init__(self) 
     self.setupUi(self) 

     self.disp.display(?????) #<---- 


    def startCounting(self): 
     if not self.counting: 
      self.counting = True 
      thread = threading.Thread(target=self.something) 
      thread.start() 

    def something(self): 
     for i in range(100): 
      self.counter.emit(int(i)) 
      sleep(0.5) 
     self.counting = False 


if __name__ == "__main__": 
    app = QApplication(sys.argv) 
    window = MainWindow() 
    window.show() 
    sys.exit(app.exec_()) 

的.ui文件：

<?xml version="1.0" encoding="UTF-8"?> 
<ui version="4.0"> 
<class>MainWindow</class> 
<widget class="QMainWindow" name="MainWindow"> 
    <property name="geometry"> 
    <rect> 
    <x>0</x> 
    <y>0</y> 
    <width>577</width> 
    <height>504</height> 
    </rect> 
    </property> 
    <property name="windowTitle"> 
    <string>MainWindow</string> 
    </property> 
    <widget class="QWidget" name="centralwidget"> 
    <layout class="QGridLayout" name="gridLayout"> 
    <item row="0" column="0"> 
    <widget class="QLCDNumber" name="disp"/> 
    </item> 
    </layout> 
    </widget> 
    <widget class="QMenuBar" name="menubar"> 
    <property name="geometry"> 
    <rect> 
    <x>0</x> 
    <y>0</y> 
    <width>577</width> 
    <height>24</height> 
    </rect> 
    </property> 
    </widget> 
    <widget class="QStatusBar" name="statusbar"/> 
</widget> 
<resources/> 
<connections/> 
</ui> 

Answer 1

你就要成功了，你是發射具有但是你的信號沒有連接到任何函數的新值的信號，你只需要創建一個函數來更新QLCDNumber的價值和你的信號計數器連接到此功能：

import sys 
import threading 

from PyQt4.QtCore import * 
from PyQt4.QtGui import * 
from PyQt4 import uic 

from time import sleep 


Ui_MainWindow, QtBaseClass = uic.loadUiType("./disp.ui") 

class MainWindow(QMainWindow, Ui_MainWindow): 
    counter = pyqtSignal(int) 
    counting = False 

    def __init__(self): 
     QMainWindow.__init__(self) 
     Ui_MainWindow.__init__(self) 
     self.setupUi(self) 

     self.counter.connect(self.update_lcd) 
     # self.startCounting() 

    def update_lcd(self, value): 
     self.disp.display(value) 

    def startCounting(self): 
     if not self.counting: 
      self.counting = True 
      thread = threading.Thread(target=self.something) 
      thread.start() 

    def something(self): 
     for i in range(100): 
      self.counter.emit(int(i)) 
      sleep(0.5) 
     self.counting = False 


if __name__ == "__main__": 
    app = QApplication(sys.argv) 
    window = MainWindow() 
    window.show() 
    sys.exit(app.exec_()) 

我建議使用QThread或QRunnable而不是線程模塊來開始後臺任務。差異的一個很好的解釋可以發現here。