Qt官方示例-计算器

• 2019 年 11 月 24 日
• 筆記

该示例显示了如何使用信号和槽来实现计算器小部件的功能，以及如何使用QGridLayout将子小部件放置在网格中。

• 通过绑定不同的按钮和不同的槽函数实现计算功能。

private slots:      void digitClicked();      void unaryOperatorClicked();      void additiveOperatorClicked();      void multiplicativeOperatorClicked();      void equalClicked();      void pointClicked();      void changeSignClicked();      void backspaceClicked();      void clear();      void clearAll();      void clearMemory();      void readMemory();      void setMemory();      void addToMemory();

• 创建执行按钮。

for (int i = 0; i < NumDigitButtons; ++i) {      digitButtons[i] = createButton(QString::number(i), SLOT(digitClicked())); /* 绑定数字按钮 */  }    Button *pointButton = createButton(tr("."), SLOT(pointClicked()));  Button *changeSignButton = createButton(tr("302261"), SLOT(changeSignClicked()));    Button *backspaceButton = createButton(tr("Backspace"), SLOT(backspaceClicked()));  Button *clearButton = createButton(tr("Clear"), SLOT(clear()));  Button *clearAllButton = createButton(tr("Clear All"), SLOT(clearAll()));    Button *clearMemoryButton = createButton(tr("MC"), SLOT(clearMemory()));  Button *readMemoryButton = createButton(tr("MR"), SLOT(readMemory()));  Button *setMemoryButton = createButton(tr("MS"), SLOT(setMemory()));  Button *addToMemoryButton = createButton(tr("M+"), SLOT(addToMemory()));    Button *divisionButton = createButton(tr("303267"), SLOT(multiplicativeOperatorClicked()));  Button *timesButton = createButton(tr("303227"), SLOT(multiplicativeOperatorClicked()));  Button *minusButton = createButton(tr("-"), SLOT(additiveOperatorClicked()));  Button *plusButton = createButton(tr("+"), SLOT(additiveOperatorClicked()));    Button *squareRootButton = createButton(tr("Sqrt"), SLOT(unaryOperatorClicked()));  Button *powerButton = createButton(tr("x302262"), SLOT(unaryOperatorClicked()));  Button *reciprocalButton = createButton(tr("1/x"), SLOT(unaryOperatorClicked()));  Button *equalButton = createButton(tr("="), SLOT(equalClicked()));

• 创建按钮的同时绑定相关槽函数。

Button *Calculator::createButton(const QString &text, const char *member)  {      Button *button = new Button(text);      connect(button, SIGNAL(clicked()), this, member);      return button;  }

• 加入布局。

QGridLayout *mainLayout = new QGridLayout;  //! [5] //! [6]  mainLayout->setSizeConstraint(QLayout::SetFixedSize);  mainLayout->addWidget(display, 0, 0, 1, 6);  mainLayout->addWidget(backspaceButton, 1, 0, 1, 2);  mainLayout->addWidget(clearButton, 1, 2, 1, 2);  mainLayout->addWidget(clearAllButton, 1, 4, 1, 2);    mainLayout->addWidget(clearMemoryButton, 2, 0);  mainLayout->addWidget(readMemoryButton, 3, 0);  mainLayout->addWidget(setMemoryButton, 4, 0);  mainLayout->addWidget(addToMemoryButton, 5, 0);    for (int i = 1; i < NumDigitButtons; ++i) {      int row = ((9 - i) / 3) + 2;      int column = ((i - 1) % 3) + 1;      mainLayout->addWidget(digitButtons[i], row, column);  }    mainLayout->addWidget(digitButtons[0], 5, 1);  mainLayout->addWidget(pointButton, 5, 2);  mainLayout->addWidget(changeSignButton, 5, 3);    mainLayout->addWidget(divisionButton, 2, 4);  mainLayout->addWidget(timesButton, 3, 4);  mainLayout->addWidget(minusButton, 4, 4);  mainLayout->addWidget(plusButton, 5, 4);    mainLayout->addWidget(squareRootButton, 2, 5);  mainLayout->addWidget(powerButton, 3, 5);  mainLayout->addWidget(reciprocalButton, 4, 5);  mainLayout->addWidget(equalButton, 5, 5);  setLayout(mainLayout);

关于更多

• 在QtCreator软件可以找到：

• 或在以下Qt安装目录找到：

C:Qt{你的Qt版本}Examples{你的Qt版本}widgetswidgetscalculator

• 相关链接

https://doc.qt.io/qt-5/qtwidgets-widgets-calculator-example.html