轻量级Qt键盘-实现篇

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介绍该键盘项目的代码实现。

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1.布局

采用垂直布局

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QHBoxLayout *h1();
QHBoxLayout *h2();
QHBoxLayout *h3();
QHBoxLayout *h4();

QVBoxLayout *layout = new QVBoxLayout();
layout->setSpacing(BUTTON_SPACING_RATIO*height());
layout->addLayout(h1());
layout->addLayout(h2());
layout->addLayout(h3());
layout->addLayout(h4());

mainLayout->addStretch();
mainLayout->addLayout(layout);
mainLayout->addStretch();

2.KeyButton生成

  • 从第一行的键盘布局代码中可以看到，使用for循环创建KeyButton。
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    QHBoxLayout *Keyboard::h1()
    {
        QHBoxLayout *h = new QHBoxLayout;
        ...
        for (int i = 0; i < modeListBar1.count(); i++) {
            KeyButton *button = createButton(modeListBar1.at(i));
            h->addWidget(button);
        }

        ...
    }

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  • 创建createButton中传递按键的三个状态信息(以第一行为例)。
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    KeyButton *Keyboard::createButton(QList<KeyButton::Mode> modes)
    {
        KeyButton *button = new KeyButton(modes, this);
        button->onReponse(this, SLOT(onKeyPressed(const int&, const QString&)));
        button->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
        return button;
    }

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  • 每一行内容分别分为小写状态，大写状态，字符状态。 
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    const QList<Modes> modeListBar1 = {
        {{Qt::Key_Q, "q"}, {Qt::Key_Q, "Q"}, {Qt::Key_1, "1"}},
        {{Qt::Key_W, "w"}, {Qt::Key_W, "W"}, {Qt::Key_2, "2"}},
        {{Qt::Key_E, "e"}, {Qt::Key_E, "E"}, {Qt::Key_3, "3"}},
        {{Qt::Key_R, "r"}, {Qt::Key_R, "R"}, {Qt::Key_4, "4"}},
        {{Qt::Key_T, "t"}, {Qt::Key_T, "T"}, {Qt::Key_5, "5"}},
        {{Qt::Key_Y, "y"}, {Qt::Key_Y, "Y"}, {Qt::Key_6, "6"}},
        {{Qt::Key_U, "u"}, {Qt::Key_U, "U"}, {Qt::Key_7, "7"}},
        {{Qt::Key_I, "i"}, {Qt::Key_I, "I"}, {Qt::Key_8, "8"}},
        {{Qt::Key_O, "o"}, {Qt::Key_O, "O"}, {Qt::Key_9, "9"}},
        {{Qt::Key_P, "p"}, {Qt::Key_P, "P"}, {Qt::Key_0, "0"}},
    };

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  • 根据传递的信息默认显示小写状态的内容。
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    KeyButton::KeyButton(const QList<KeyButton::Mode> modes, QWidget *parent) :
        QPushButton(parent)
    {
        ...
        if (!modes.isEmpty()) {
            m_preMode = m_mode = m_modes.first();
            setText(m_mode.display);
        }

        connect(this, SIGNAL(pressed()), this, SLOT(onPressed()));
    }

3.按键状态切换

  • 键盘存在三种形态，小写状态，大写状态，字符状态。
  • 一个按键存在三种状态，意味​按键有三种状态切换，当键盘Keyboard类绑定切换状态的按键，进行响应的操作。当键盘Keyboard类绑定切换状态的按键，进行响应的操作。

  • 通过按键的状态值来绑定Keyboard的处理信号(switchCapsLock()，switchSpecialChar())。

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    void Keyboard::resizeButton()
    {
        foreach (KeyButton *button, findChildren<KeyButton *>()) {
            ...

            switch (button->mode().key) {
              case Qt::Key_CapsLock:
                  ...
                  connect(button, 
                          SIGNAL(pressed()), 
                          this, 
                          SLOT(switchCapsLock()), 
                          Qt::UniqueConnection);
                  break;
              case Qt::Key_Mode_switch:
                  ...
                  connect(button, 
                          SIGNAL(pressed()), 
                          this, 
                          SLOT(switchSpecialChar()), 
                          Qt::UniqueConnection);
                  break;
              default:
                  break;
            }
        }

        ...
    }

  • 触发切换大写状态，遍历设置每个按键的switchCapsLock()函数。

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    void Keyboard::switchCapsLock()
    {
        QList<KeyButton *> buttons = findChildren<KeyButton *>();
        foreach(KeyButton *button, buttons)
            button->switchCapsLock();
    }

  • KeyButton的switchCapsLock()函数切换按键显示的内容。

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    void KeyButton::switchCapsLock()
    {
        if (m_mode.type == SpecialChar)
            return;

        m_preMode = m_mode;
        m_mode = find(m_mode.type == LowerCase ? UpperCase : LowerCase);
        setText(m_mode.display);
    }

4.发送模拟事件到焦点窗口

  • 当创建按键的同时也会绑定AbstractKeyboard的onKeyPressed槽函数。

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    KeyButton *button = new KeyButton(modes, this);
    button->onReponse(this, SLOT(onKeyPressed(const int&, const QString&)));

  • 使用QApplication的sendEvent发送按键事件到焦点窗口。

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    void AbstractKeyboard::onKeyPressed(int key, QString value) 
    {
        QWidget *receiver = QApplication::focusWidget();
        if (!receiver)
            return;

        QKeyEvent keyPress(QEvent::KeyPress,     key, Qt::NoModifier, value);
        QKeyEvent keyRelease(QEvent::KeyRelease, key, Qt::NoModifier, value);

        QApplication::sendEvent(receiver, &keyPress);
        QApplication::sendEvent(receiver, &keyRelease);
    }