PyQt5：计算器UI(1)

来源：互联网发布：费米估算法是什么编辑：程序博客网时间：2024/05/02 08:25

对照PyQt5的计算器demo 和 Qt4.7的计算器demo ，初步了解信号槽、函数和UI的写法。

大概了解了下UI的写法

1. main.cpp

在Qt C++ 里面首先入口函数是：

int main(int argc, char *argv[]){    QApplication app(argc, argv);    Calculator calc;    calc.show();    return app.exec();}

在PyQt5里面入口函数

if __name__ == '__main__':    import sys    app = QApplication(sys.argv)    calc = Calculator()    calc.show()    sys.exit(app.exec_())

同理都需要库的头文件

C++写法：

#include <QApplication>#include <QToolButton>#include <QGirdLayout>

PyQt写法：

from PyQt5.QtCore import Qtfrom PyQt5.QtWidgets import (QApplication, QGridLayout, QLayout, QLineEdit,         QSizePolicy, QToolButton, QWidget)

2.Calculator类

class Calculator(QWidget):        def __init__(self,  parent = None):        super(Calculator,  self).__init__(parent)

可以理解为构造函数，初始化内容

接下来可以new一些button

        #[3]        self.display = QLineEdit('0')     # new QLineEdit        self.display.setReadOnly(True)   # 设置只读        self.display.setAlignment(Qt.AlignRight)  # 设置文字从右向左显示        self.display.setMaxLength(15)   # set max length        #[3]        #[4]        font = self.display.font()        font.setPointSize(font.pointSize() + 8)        self.display.setFont(font)        #[4]                #[5] create button  0, 1, 2, .... 9        self.digitButtons = []                for i in range(Calculator.NumDigitButtons):            self.digitButtons.append(self.createButton(str(i), self.digitClicked))        #[5]                #[7] create button         self.pointButton = self.createButton(".",  self.pointClicked)        self.changeSignButton = self.createButton(u"\N{PLUS-MINUS SIGN}",  self.changeSignClicked)                self.backspaceButton = self.createButton("Backspace",  self.backspaceClicked)        self.clearButton = self.createButton("Clear",  self.clearClicked)        self.clearAllButton = self.createButton("Clear All",  self.clearAll)                self.clearMemoryButton = self.createButton("MC",  self.clearMemory)        self.readMemoryButton = self.createButton("MR",  self.readMemory)        self.setMemoryButton = self.createButton("MS",  self.setMemory)        self.addToMemoryButton = self.createButton("M+",  self.addToMemory)                # / * - +          self.divisionButton = self.createButton(u"\N{DIVISION SIGN}", self.multiplicativeOperatorClicked)        self.timesButton = self.createButton(u"\N{MULTIPLICATION SIGN}", self.multiplicativeOperatorClicked)        self.minusButton = self.createButton("-", self.additiveOperatorClicked)        self.plusButton = self.createButton("+", self.additiveOperatorClicked)                self.squareRootButton = self.createButton("Sqrt", self.unaryOperatorClicked)        self.powerButton = self.createButton(u"x\N{SUPERSCRIPT TWO}", self.unaryOperatorClicked)        self.reciprocalButton = self.createButton("1/x", self.unaryOperatorClicked)        self.equalButton = self.createButton("=", self.equalClicked)

然后适用QGridLayout布局

#[9]        mainLayout = QGridLayout()        mainLayout.setSizeConstraint(QLayout.SetFixedSize)                mainLayout.addWidget(self.display, 0, 0, 1, 6)        mainLayout.addWidget(self.backspaceButton, 1, 0, 1, 2)        mainLayout.addWidget(self.clearButton, 1, 2, 1, 2)        mainLayout.addWidget(self.clearAllButton, 1, 4, 1, 2)                mainLayout.addWidget(self.clearMemoryButton, 2, 0)        mainLayout.addWidget(self.readMemoryButton, 3, 0)        mainLayout.addWidget(self.setMemoryButton, 4, 0)        mainLayout.addWidget(self.addToMemoryButton, 5, 0)                for i in range(1,  Calculator.NumDigitButtons):            row = ((9 - i) / 3) + 2            column = ((i -1) % 3) + 1            mainLayout.addWidget(self.digitButtons[i],  row,  column)                 mainLayout.addWidget(self.digitButtons[0], 5, 1)        mainLayout.addWidget(self.pointButton, 5, 2)        mainLayout.addWidget(self.changeSignButton, 5, 3)               mainLayout.addWidget(self.divisionButton, 2, 4)        mainLayout.addWidget(self.timesButton, 3, 4)        mainLayout.addWidget(self.minusButton, 4, 4)        mainLayout.addWidget(self.plusButton, 5, 4)                 mainLayout.addWidget(self.squareRootButton, 2, 5)        mainLayout.addWidget(self.powerButton, 3, 5)        mainLayout.addWidget(self.reciprocalButton, 4, 5)        mainLayout.addWidget(self.equalButton, 5, 5)        self.setLayout(mainLayout)

这里面动态创建按钮并连接槽函数：

def createButton(self, text, member):        button = Button(text)        button.clicked.connect(member) # member = SLOT(函数名)        return button

3. Button 类继承 QToolButton 主要设置了大小

class Button(QToolButton):    def __init__(self, text, parent = None):        super(Button, self).__init__(parent)                self.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Preferred)        self.setText(text)            def sizeHint(self):        size = super(Button, self).sizeHint()        size.setHeight(size.height() + 20)        size.setWidth(max(size.width(), size.height()))        return size

4. Calculator类中的按钮连接的槽函数

主要要和上面的def对齐

def digitClicked(self):        print("digitClicked")

这里都没有实现函数，只是点击打印了信息。

.py整体文件如下：

#!/usr/bin/env pythonimport math from PyQt5.QtCore import Qtfrom PyQt5.QtWidgets import (QApplication, QGridLayout, QLayout, QLineEdit,         QSizePolicy, QToolButton, QWidget)class Button(QToolButton):    def __init__(self, text, parent = None):        super(Button, self).__init__(parent)                self.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Preferred)        self.setText(text)            def sizeHint(self):        size = super(Button, self).sizeHint()        size.setHeight(size.height() + 20)        size.setWidth(max(size.width(), size.height()))        return size#[2] Calculator inherit QWidgetclass Calculator(QWidget):    NumDigitButtons = 10  # C++ enum         def __init__(self,  parent = None):        super(Calculator,  self).__init__(parent)                #[3]        self.display = QLineEdit('0')     # new QLineEdit        self.display.setReadOnly(True)   # 设置只读        self.display.setAlignment(Qt.AlignRight)  # 设置文字从右向左显示        self.display.setMaxLength(15)   # set max length        #[3]        #[4]        font = self.display.font()        font.setPointSize(font.pointSize() + 8)        self.display.setFont(font)        #[4]                #[5] create button  0, 1, 2, .... 9        self.digitButtons = []                for i in range(Calculator.NumDigitButtons):            self.digitButtons.append(self.createButton(str(i), self.digitClicked))        #[5]                #[7] create button         self.pointButton = self.createButton(".",  self.pointClicked)        self.changeSignButton = self.createButton(u"\N{PLUS-MINUS SIGN}",  self.changeSignClicked)                self.backspaceButton = self.createButton("Backspace",  self.backspaceClicked)        self.clearButton = self.createButton("Clear",  self.clearClicked)        self.clearAllButton = self.createButton("Clear All",  self.clearAll)                self.clearMemoryButton = self.createButton("MC",  self.clearMemory)        self.readMemoryButton = self.createButton("MR",  self.readMemory)        self.setMemoryButton = self.createButton("MS",  self.setMemory)        self.addToMemoryButton = self.createButton("M+",  self.addToMemory)                # / * - +          self.divisionButton = self.createButton(u"\N{DIVISION SIGN}", self.multiplicativeOperatorClicked)        self.timesButton = self.createButton(u"\N{MULTIPLICATION SIGN}", self.multiplicativeOperatorClicked)        self.minusButton = self.createButton("-", self.additiveOperatorClicked)        self.plusButton = self.createButton("+", self.additiveOperatorClicked)                self.squareRootButton = self.createButton("Sqrt", self.unaryOperatorClicked)        self.powerButton = self.createButton(u"x\N{SUPERSCRIPT TWO}", self.unaryOperatorClicked)        self.reciprocalButton = self.createButton("1/x", self.unaryOperatorClicked)        self.equalButton = self.createButton("=", self.equalClicked)        #[7]                #[9]        mainLayout = QGridLayout()        mainLayout.setSizeConstraint(QLayout.SetFixedSize)                mainLayout.addWidget(self.display, 0, 0, 1, 6)        mainLayout.addWidget(self.backspaceButton, 1, 0, 1, 2)        mainLayout.addWidget(self.clearButton, 1, 2, 1, 2)        mainLayout.addWidget(self.clearAllButton, 1, 4, 1, 2)                mainLayout.addWidget(self.clearMemoryButton, 2, 0)        mainLayout.addWidget(self.readMemoryButton, 3, 0)        mainLayout.addWidget(self.setMemoryButton, 4, 0)        mainLayout.addWidget(self.addToMemoryButton, 5, 0)                for i in range(1,  Calculator.NumDigitButtons):            row = ((9 - i) / 3) + 2            column = ((i -1) % 3) + 1            mainLayout.addWidget(self.digitButtons[i],  row,  column)                 mainLayout.addWidget(self.digitButtons[0], 5, 1)        mainLayout.addWidget(self.pointButton, 5, 2)        mainLayout.addWidget(self.changeSignButton, 5, 3)               mainLayout.addWidget(self.divisionButton, 2, 4)        mainLayout.addWidget(self.timesButton, 3, 4)        mainLayout.addWidget(self.minusButton, 4, 4)        mainLayout.addWidget(self.plusButton, 5, 4)                 mainLayout.addWidget(self.squareRootButton, 2, 5)        mainLayout.addWidget(self.powerButton, 3, 5)        mainLayout.addWidget(self.reciprocalButton, 4, 5)        mainLayout.addWidget(self.equalButton, 5, 5)        self.setLayout(mainLayout)                self.setWindowTitle("Calculator")        #[9]                    #[6] 函数未实现    def createButton(self, text, member):        button = Button(text)        button.clicked.connect(member)  # member = SLOT(函数名)        return button            def digitClicked(self):        print("digitClicked")                #[6]        #[8] function about buttons 函数未实现    def pointClicked(self):        print("pointClicked")                 def changeSignClicked(self):        print("changeSignClicked")         def backspaceClicked(self):        print("backspaceClicked")         def clearClicked(self):        print("clearClicked")         def clearAll(self):        print("clearAll")         def clearMemory(self):        print("clearMemory")            def readMemory(self):        print("readMemory")            def setMemory(self):        print("setMemory")         def addToMemory(self):        print("addToMemory")        def multiplicativeOperatorClicked(self):        print("multiplicativeOperatorClicked")        def additiveOperatorClicked(self):        print("additiveOperatorClicked")            def unaryOperatorClicked(self):        print("unaryOperatorClicked")            def equalClicked(self):        print("equalClicked")    #[8]#[1] same as C++ main.cppif __name__ == '__main__':    import sys    app = QApplication(sys.argv)    calc = Calculator()    calc.show()    sys.exit(app.exec_())

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