Qt官方示例-计算器

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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。

main_page

  • 通过绑定不同的按钮和不同的槽函数实现计算功能。 

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    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。 

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    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("\302\261"), 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("\303\267"), SLOT(multiplicativeOperatorClicked()));
    Button *timesButton = createButton(tr("\303\227"), 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("x\302\262"), 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。

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    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。

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    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：

what_find

  • 或在以下Qt安装目录找到：

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    C:\Qt\{你的Qt版本}\Examples\{你的Qt版本}\widgets\widgets\calculator

  • 相关链接

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

  • Qt君公众号回复『Qt示例』获取更多内容。