QT自制软键盘最完美、最简单、支持中文输入（二）

一、前言

二、本自制虚拟键盘特点

三、中文输入原理

四、组合键输入

五、键盘事件模拟

六、界面

七、代码

7.1 frmKeyBoard 头文件代码

7.2 frmKeyBoard 源文件代码

八、使用示例

九、效果

十、结语

一、前言

由于系统自带虚拟键盘不一定好用，也不一定好看，有的按键太小，有的电脑上可能没有自带的软键盘，干脆直接自己设计一个。

在现代的用户界面设计中，屏幕键盘是一种重要的辅助工具，特别是在触摸屏设备上。本文将深入解析一个使用Qt框架自制的屏幕键盘，具有丰富的功能和用户友好的界面，支持中文输入、组合键操作等多种特性。

之前写过一篇不带中文的屏幕键盘，本文在该基础上升级部分功能：QT自制软键盘最完美、最简单、跟自带虚拟键盘一样（一）

二、本自制虚拟键盘特点

1.支持中文输入。

2.支持组合键，例如“Ctrl+C”复制粘贴操作。

3.键盘界面保持在所有界面最上方。

4.点击键盘按钮不会改变底层文本输入框焦点。

5.通过模拟键盘点击事件完成键盘输入文本信息。

6.包含各种键盘自带符号输入。

7.长按按键可以持续重复输入键盘内容。

三、中文输入原理

资源中包含了“PinYin_Chinese.txt”文本文件，文件内容为七千多个汉字以及对应的拼音，通过加载中文拼音数据，实现了基于拼音的中文输入。在用户输入拼音时，屏幕键盘匹配对应的汉字词组，并显示在候选列表中。

加载中文汉字代码：

void frmKeyBoard::loadChineseFontData()
{
    QFile pinyin(":/PinYin_Chinese.txt");
    if (!pinyin.open(QIODevice::ReadOnly)) {
        qDebug() << "Open pinyin file failed!";
        return;
    }
    while (!pinyin.atEnd()) {
        QString buf = QString::fromUtf8(pinyin.readLine()).trimmed();
        if (buf.isEmpty())
            continue;
        /* 去除#号后的注释内容 */
        if (buf.left(1) == "#")
            continue;
        buf=buf.replace("\t"," ");

        QString pinyin = buf.mid(1,buf.size() - 1);
        QString word = buf.mid(0,1);
        QString abb;
        QStringList pinyinList = pinyin.split(" ");
        for (int i = 0; i < pinyinList.count(); i++) {
            /* 获得拼音词组的首字母(用于缩写匹配) */
            abb += pinyinList.at(i).left(1);
        }
        QList<QPair<QString, QString>> &tmp = m_data[pinyin.left(1)];
        /* 将'拼音(缩写)'和'词组'写入匹配容器 */
        tmp.append(qMakePair(abb, word));
        /* 将'拼音(全拼)'和'词组'写入匹配容器 */
        tmp.append(qMakePair(pinyin.remove(" "), word));
    }
    qDebug() << m_data.size();
    pinyin.close();
}

点击列表选择汉字输入：

void frmKeyBoard::on_listWidget_itemClicked(QListWidgetItem *item)
{
    QKeyEvent keyPress(QEvent::KeyPress, 0, m_curModifier, item->text().right(1));
    QKeyEvent keyRelease(QEvent::KeyRelease, 0, m_curModifier, item->text().right(1));
    QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
    QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    ui.listWidget->clear();
    m_showTextList.clear();
    m_curPage = 0;
    m_labelShowPinyin->clear();
    recordLitterBuf.clear();
}

另外，点击汉字对应的数字、点击空格都可以输入汉字，点击回车输入对应的英文字母，部分关键代码：


void frmKeyBoard::slotKeyButtonClicked()
{
    QPushButton* pbtn = (QPushButton*)sender();
    QString objectName = pbtn->objectName();
    if (pbtn->text().contains("Backspace")) {
        if(isChinese){
            if(recordLitterBuf.size() > 0){
                recordLitterBuf.remove(recordLitterBuf.size() - 1, 1);
                findChineseFontData(recordLitterBuf);
                if(!m_labelShowPinyin->text().isEmpty())
                    m_labelShowPinyin->setText(recordLitterBuf);
            }
        }
        else{
            QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Backspace, m_curModifier);
            QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Backspace, m_curModifier);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
        }
    }
    else if(pbtn->text() == "Space") {
        if(isChinese){
            if(ui.listWidget->count() > 0){
                //按下空格输入列表第一汉字
                on_listWidget_itemClicked(ui.listWidget->item(0));
            }
        }
        else{
            QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Space, m_curModifier, " ");
            QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Space, m_curModifier, " ");
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
        }
    }
    else if (pbtn->text().contains("Enter")) {        
        if(isChinese){
            if(!m_labelShowPinyin->text().isEmpty()){
                //按下回车输入拼音字母
                QKeyEvent keyPress(QEvent::KeyPress, 0, m_curModifier, m_labelShowPinyin->text());
                QKeyEvent keyRelease(QEvent::KeyRelease, 0,m_curModifier, m_labelShowPinyin->text());
                QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
                QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
                ui.listWidget->clear();
                m_showTextList.clear();
                m_curPage = 0;
                m_labelShowPinyin->clear();
                recordLitterBuf.clear();
            }
        }
        else{
            QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Enter, m_curModifier);
            QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Enter, m_curModifier);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
        }
    }
    else if (pbtn->text().contains("Shift")) {
        if (pbtn->isChecked()) {
            isChinese = true;
            m_curModifier = Qt::ShiftModifier;
            for (auto pbtnKey : m_letterKeys) {
                pbtnKey->setText(pbtnKey->text().toUpper());
            }
        }
        else {
            isChinese = false;
            ui.listWidget->clear();
            m_showTextList.clear();
            m_curPage = 0;
            m_labelShowPinyin->clear();
            recordLitterBuf.clear();
            m_curModifier = Qt::NoModifier;
            for (auto pbtnKey : m_letterKeys) {
                pbtnKey->setText(pbtnKey->text().toLower());
            }
        }
        QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Shift, m_curModifier);
        QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Shift, m_curModifier);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
//......
    else {
        QString symbol;
        if (ui.pushButton_shift->isChecked())
            symbol = pbtn->text().split("\n").at(0);
        else
            symbol = pbtn->text().split("\n").at(1);

        QKeyEvent keyPress(QEvent::KeyPress, m_mapSymbolKeys.value(symbol), m_curModifier, symbol);
        QKeyEvent keyRelease(QEvent::KeyRelease, m_mapSymbolKeys.value(symbol), m_curModifier, symbol);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
}

四、组合键输入

4.1 定义m_curModifier 记录当前键盘模式。

Qt::KeyboardModifier m_curModifier = Qt::NoModifier;

4.2 特殊按键选中时切换对应的按键模式

if (pbtn->text().contains("Ctrl")) {
        if(pbtn->isChecked())
            m_curModifier = Qt::ControlModifier;
        else
            m_curModifier = Qt::NoModifier;
        QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Control, m_curModifier);
        QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Control, m_curModifier);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }

五、键盘事件模拟

通过模拟键盘事件，实现了对底层文本输入框的模拟输入。这样，用户可以在使用屏幕键盘的同时，保持对其他界面元素的操作。

QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Enter, m_curModifier);
QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Enter, m_curModifier);
QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);

另外，通过qApp->focusWidget()获取当前焦点所在的窗口，可以将键盘模拟输入到各个窗口的输入框中。

六、界面

界面新增了一个QListWidget用于显示候选汉字列表，列表方向从左至右。

七、代码

7.1 frmKeyBoard 头文件代码

#pragma once
#pragma execution_character_set("utf-8")

#include <QDialog>
#include "ui_frmKeyBoard.h"
#include <QPushButton>
#include <QKeyEvent>
#include <QDebug>
#include <QStyle>
#include <QListWidgetItem>
#include <QLabel>
#include <QVBoxLayout>
#include <QToolTip>

class frmKeyBoard : public QDialog
{
	Q_OBJECT

public:
	frmKeyBoard(QWidget *parent = nullptr);
	~frmKeyBoard();

	void initFocusWidget(QWidget*);

private slots:
	void slotKeyButtonClicked();
	void slotKeyLetterButtonClicked();
	void slotKeyNumberButtonClicked();

    void on_listWidget_itemClicked(QListWidgetItem *item);
    void on_toolButton_lastPage_clicked();
    void on_toolButton_nextPage_clicked();

private:
	Ui::frmKeyBoardClass ui;
	void initFrm();
	void initStyleSheet();

    void loadChineseFontData();
    void findChineseFontData(QString text);
    void addOneItem(QString text);

    QMap<QString, QList<QPair<QString, QString>>> m_data;
    bool isChinese = false;
    QString recordLitterBuf;

	QVector<QPushButton*> m_letterKeys;
	QVector<QPushButton*> m_NumberKeys;

	QMap<QString, Qt::Key> m_mapSymbolKeys;

    QStringList m_showTextList;
    int m_curPage = 0;

    QLabel* m_labelShowPinyin;

    Qt::KeyboardModifier m_curModifier = Qt::NoModifier;
};

7.2 frmKeyBoard 源文件代码

#include "frmKeyBoard.h"

frmKeyBoard::frmKeyBoard(QWidget *parent)
    : QDialog(parent)
{
    ui.setupUi(this);

    this->setWindowFlags(Qt::WindowStaysOnTopHint | Qt::WindowDoesNotAcceptFocus);
    this->setWindowTitle("屏幕键盘（源客V）");
    this->setWindowModality(Qt::WindowModal);
    this->setAttribute(Qt::WA_DeleteOnClose);

    this->initFrm();
    this->initStyleSheet();
    this->loadChineseFontData();
}

frmKeyBoard::~frmKeyBoard()
{
}

void frmKeyBoard::initFrm()
{
    m_letterKeys.clear();
    m_NumberKeys.clear();
    QList<QPushButton*> pbtns = this->findChildren<QPushButton*>();
    foreach(QPushButton * pbtn, pbtns) {
        pbtn->setAutoRepeat(true);    //允许自动重复
        pbtn->setAutoRepeatDelay(500);//设置重复操作的时延

        if (pbtn->text() >= 'a' && pbtn->text() <= 'z') {
            connect(pbtn, &QPushButton::clicked, this, &frmKeyBoard::slotKeyLetterButtonClicked);
            m_letterKeys.push_back(pbtn);
        }
        else if (pbtn->text().toInt() > 0 && pbtn->text().toInt() <= 9 || pbtn->text() == "0") {
            connect(pbtn, &QPushButton::clicked, this, &frmKeyBoard::slotKeyNumberButtonClicked);
            m_NumberKeys.push_back(pbtn);
        }
        else{
            connect(pbtn, &QPushButton::clicked, this, &frmKeyBoard::slotKeyButtonClicked);
        }
    }

    //添加label显示拼音
    m_labelShowPinyin = new QLabel();
    QVBoxLayout* vLayout = new QVBoxLayout();
    vLayout->addWidget(m_labelShowPinyin);
    vLayout->addStretch();
    ui.listWidget->setLayout(vLayout);

    m_mapSymbolKeys.insert("~", Qt::Key_AsciiTilde);
    m_mapSymbolKeys.insert("`", Qt::Key_nobreakspace);
    m_mapSymbolKeys.insert("-", Qt::Key_Minus);
    m_mapSymbolKeys.insert("_", Qt::Key_Underscore);
    m_mapSymbolKeys.insert("+", Qt::Key_Plus);
    m_mapSymbolKeys.insert("=", Qt::Key_Equal);
    m_mapSymbolKeys.insert(",", Qt::Key_Comma);
    m_mapSymbolKeys.insert(".", Qt::Key_Period);
    m_mapSymbolKeys.insert("/", Qt::Key_Slash);
    m_mapSymbolKeys.insert("<", Qt::Key_Less);
    m_mapSymbolKeys.insert(">", Qt::Key_Greater);
    m_mapSymbolKeys.insert("?", Qt::Key_Question);
    m_mapSymbolKeys.insert("[", Qt::Key_BracketLeft);
    m_mapSymbolKeys.insert("]", Qt::Key_BracketRight);
    m_mapSymbolKeys.insert("{", Qt::Key_BraceLeft);
    m_mapSymbolKeys.insert("}", Qt::Key_BraceRight);
    m_mapSymbolKeys.insert("|", Qt::Key_Bar);
    m_mapSymbolKeys.insert("\\", Qt::Key_Backslash);
    m_mapSymbolKeys.insert(":", Qt::Key_Colon);
    m_mapSymbolKeys.insert(";", Qt::Key_Semicolon);
    m_mapSymbolKeys.insert("\"", Qt::Key_QuoteLeft);
    m_mapSymbolKeys.insert("'", Qt::Key_Apostrophe);
}

void frmKeyBoard::initStyleSheet()
{
    QString qss;
    qss += "QWidget{ background-color:rgb(26,26,26)}";    
    qss += "QToolButton{ color:white; font:bold 11pt;}";
    qss += "QLabel{ color:white; font:13pt;}";
    qss += "QListWidget{ color:white; border:none; padding-bottom:10px; }";
    qss += "QListWidget::item:hover,QListWidget::item:selected{font:bold; color:yellow; background-color:rgba(0,0,0,0)}";
    qss += "QPushButton{ color:white; background-color:rgb(51,51,51); height:50px; font-size:bold 15pt; border:1px solid rgb(26,26,26); border-radius: 0px; min-width:50px;}";
    qss += "QPushButton:hover{background-color:rgb(229,229,229); color:black;}";
    qss += "QPushButton:pressed,QPushButton:checked{background-color:rgb(0,118,215);}";
    qss += "#pushButton_closeKeyboard{background-color:rgba(0,0,0,0); border:0px}";
    qss += "#pushButton_closeKeyboard:hover{background-color:#b30220;}";
    qss += "#pushButton_space{min-width:500px;}";
    qss += "#pushButton_backspace,#pushButton_shift{min-width:100px;}";
    qss += "#pushButton_enter{min-width:120px;}";
    qss += "#pushButton_tab,#pushButton_ctrl{min-width:70px;}";
    qss += "#pushButton_capsLock{min-width:80px;}";
    qss += "#pushButton_up{min-width:150px;}";
    this->setStyleSheet(qss);
}

void frmKeyBoard::loadChineseFontData()
{
    QFile pinyin(":/PinYin_Chinese.txt");
    if (!pinyin.open(QIODevice::ReadOnly)) {
        qDebug() << "Open pinyin file failed!";
        return;
    }
    while (!pinyin.atEnd()) {
        QString buf = QString::fromUtf8(pinyin.readLine()).trimmed();
        if (buf.isEmpty())
            continue;
        /* 去除#号后的注释内容 */
        if (buf.left(1) == "#")
            continue;
        buf=buf.replace("\t"," ");

        QString pinyin = buf.mid(1,buf.size() - 1);
        QString word = buf.mid(0,1);
        QString abb;
        QStringList pinyinList = pinyin.split(" ");
        for (int i = 0; i < pinyinList.count(); i++) {
            /* 获得拼音词组的首字母(用于缩写匹配) */
            abb += pinyinList.at(i).left(1);
        }
        QList<QPair<QString, QString>> &tmp = m_data[pinyin.left(1)];
        /* 将'拼音(缩写)'和'词组'写入匹配容器 */
        tmp.append(qMakePair(abb, word));
        /* 将'拼音(全拼)'和'词组'写入匹配容器 */
        tmp.append(qMakePair(pinyin.remove(" "), word));
    }
    qDebug() << m_data.size();
    pinyin.close();
}

void frmKeyBoard::findChineseFontData(QString text)
{
    QString lowerText = text.toLower();
    m_labelShowPinyin->setText(lowerText);
    for (int i = 0; i < ui.listWidget->count(); i++) {
        QListWidgetItem *item = ui.listWidget->takeItem(i);
        delete item;
        item = NULL;
    }
    ui.listWidget->clear();
    m_showTextList.clear();
    m_curPage = 0;

    if(lowerText.count() <= 0)
        return;

    const QList<QPair<QString, QString> > &tmp = m_data[lowerText.left(1)];
    bool fond = false;
    for (int i = 0; i < tmp.count(); i++) {
        const QPair<QString, QString> &each = tmp.at(i);
        if (each.first.left(lowerText.count()) != lowerText)
            continue;
        fond = true;
        addOneItem(each.second);
        m_showTextList.push_back(each.second);
    }
    if(!fond){
        if(recordLitterBuf.count() > 1){
            recordLitterBuf = recordLitterBuf.right(1);
            findChineseFontData(recordLitterBuf);
        }
        else{
            QKeyEvent keyPress(QEvent::KeyPress, int(recordLitterBuf.at(0).toLatin1()), m_curModifier, recordLitterBuf);
            QKeyEvent keyRelease(QEvent::KeyRelease, int(recordLitterBuf.at(0).toLatin1()), m_curModifier, recordLitterBuf);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
        }
    }
}

void frmKeyBoard::addOneItem(QString text)
{
    if(ui.listWidget->count() >= 9)
        return;
    QString itemText = QString("%1.%2").arg(ui.listWidget->count() + 1).arg(text);
    QListWidgetItem *item = new QListWidgetItem(itemText);
    QFont font;
    font.setPointSize(15);
    font.setBold(true);
    font.setWeight(50);
    item->setFont(font);
    /* 设置文字居中 */
    item->setTextAlignment(Qt::AlignBottom | Qt::AlignHCenter);
    bool isChineseFlag = QRegExp("^[\u4E00-\u9FA5]+").indexIn(text.left(1)) != -1;

    int width = font.pointSize();
    if (isChineseFlag)
        width += itemText.count()*font.pointSize()*1.5;
    else
        width += itemText.count()*font.pointSize()*2/3;

    item->setSizeHint(QSize(width, 50));
    ui.listWidget->addItem(item);
}

void frmKeyBoard::slotKeyButtonClicked()
{
    QPushButton* pbtn = (QPushButton*)sender();
    QString objectName = pbtn->objectName();
    if (pbtn->text().contains("Backspace")) {
        if(isChinese){
            if(recordLitterBuf.size() > 0){
                recordLitterBuf.remove(recordLitterBuf.size() - 1, 1);
                findChineseFontData(recordLitterBuf);
                if(!m_labelShowPinyin->text().isEmpty())
                    m_labelShowPinyin->setText(recordLitterBuf);
            }
        }
        else{
            QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Backspace, m_curModifier);
            QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Backspace, m_curModifier);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
        }
    }
    else if (pbtn->text().contains("Caps")) {
        if (pbtn->isChecked()) {
            for (auto pbtnKey : m_letterKeys) {
                pbtnKey->setText(pbtnKey->text().toUpper());
            }
        }
        else {
            for (auto pbtnKey : m_letterKeys) {
                pbtnKey->setText(pbtnKey->text().toLower());
            }
        }
    }
    else if(pbtn->text() == "Space") {
        if(isChinese){
            if(ui.listWidget->count() > 0){
                on_listWidget_itemClicked(ui.listWidget->item(0));
            }
        }
        else{
            QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Space, m_curModifier, " ");
            QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Space, m_curModifier, " ");
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
        }
    }
    else if (pbtn->text().contains("Tab")) {
        QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Tab, m_curModifier);
        QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Tab, m_curModifier);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
    else if (pbtn->text().contains("Enter")) {        
        if(isChinese){
            if(!m_labelShowPinyin->text().isEmpty()){
                QKeyEvent keyPress(QEvent::KeyPress, 0, m_curModifier, m_labelShowPinyin->text());
                QKeyEvent keyRelease(QEvent::KeyRelease, 0,m_curModifier, m_labelShowPinyin->text());
                QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
                QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
                ui.listWidget->clear();
                m_showTextList.clear();
                m_curPage = 0;
                m_labelShowPinyin->clear();
                recordLitterBuf.clear();
            }
        }
        else{
            QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Enter, m_curModifier);
            QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Enter, m_curModifier);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
        }
    }
    else if (pbtn->text().contains("Shift")) {
        if (pbtn->isChecked()) {
            isChinese = true;
            m_curModifier = Qt::ShiftModifier;
            for (auto pbtnKey : m_letterKeys) {
                pbtnKey->setText(pbtnKey->text().toUpper());
            }
        }
        else {
            isChinese = false;
            ui.listWidget->clear();
            m_showTextList.clear();
            m_curPage = 0;
            m_labelShowPinyin->clear();
            recordLitterBuf.clear();
            m_curModifier = Qt::NoModifier;
            for (auto pbtnKey : m_letterKeys) {
                pbtnKey->setText(pbtnKey->text().toLower());
            }
        }
        QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Shift, m_curModifier);
        QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Shift, m_curModifier);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
    else if (pbtn->text().contains("Ctrl")) {
        if(pbtn->isChecked())
            m_curModifier = Qt::ControlModifier;
        else
            m_curModifier = Qt::NoModifier;
        QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Control, m_curModifier);
        QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Control, m_curModifier);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
    else if (pbtn->text().contains("Win")) {
        QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Menu, m_curModifier);
        QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Menu, m_curModifier);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
    else if (pbtn->text().contains("Alt")) {
        if(pbtn->isChecked())
            m_curModifier = Qt::AltModifier;
        else
            m_curModifier = Qt::NoModifier;
        QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Alt, m_curModifier);
        QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Alt, m_curModifier);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
    else if (pbtn->text().contains("↑")) {
        QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Up, m_curModifier);
        QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Up, m_curModifier);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
    else if (pbtn->text().contains("↓")) {
        QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Down, m_curModifier);
        QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Down, m_curModifier);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
    else if (pbtn->text().contains("←")) {
        QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Left, m_curModifier);
        QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Left, m_curModifier);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
    else if (pbtn->text().contains("→")) {
        QKeyEvent keyPress(QEvent::KeyPress, Qt::Key_Right, m_curModifier);
        QKeyEvent keyRelease(QEvent::KeyRelease, Qt::Key_Right, m_curModifier);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
    else {
        QString symbol;
        if (ui.pushButton_shift->isChecked())
            symbol = pbtn->text().split("\n").at(0);
        else
            symbol = pbtn->text().split("\n").at(1);

        QKeyEvent keyPress(QEvent::KeyPress, m_mapSymbolKeys.value(symbol), m_curModifier, symbol);
        QKeyEvent keyRelease(QEvent::KeyRelease, m_mapSymbolKeys.value(symbol), m_curModifier, symbol);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
        QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    }
}


void frmKeyBoard::slotKeyLetterButtonClicked()
{
    QPushButton* pbtn = (QPushButton*)sender();
    if (pbtn->text() >= 'a' && pbtn->text() <= 'z') {
        if(isChinese){
            recordLitterBuf+=pbtn->text().toLower();
            findChineseFontData(recordLitterBuf);
        }
        else{
            ui.listWidget->clear();
            m_showTextList.clear();
            m_curPage = 0;
            m_labelShowPinyin->clear();
            recordLitterBuf.clear();
            QKeyEvent keyPress(QEvent::KeyPress, int(pbtn->text().at(0).toLatin1()) - 32, m_curModifier, pbtn->text());
            QKeyEvent keyRelease(QEvent::KeyRelease, int(pbtn->text().at(0).toLatin1()) - 32, m_curModifier, pbtn->text());
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
        }
    }
    else if (pbtn->text() >= 'A' && pbtn->text() <= 'Z') {
        if(isChinese){
            recordLitterBuf+=pbtn->text().toLower();
            findChineseFontData(recordLitterBuf);
        }
        else{
            ui.listWidget->clear();
            m_showTextList.clear();
            m_curPage = 0;
            m_labelShowPinyin->clear();
            recordLitterBuf.clear();
            QKeyEvent keyPress(QEvent::KeyPress, int(pbtn->text().at(0).toLatin1()), m_curModifier, pbtn->text());
            QKeyEvent keyRelease(QEvent::KeyRelease, int(pbtn->text().at(0).toLatin1()), m_curModifier, pbtn->text());
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
            QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
        }
    }
    if (ui.pushButton_ctrl->isChecked())
        ui.pushButton_ctrl->setChecked(false);
    if (ui.pushButton_win->isChecked())
        ui.pushButton_win->setChecked(false);
    if (ui.pushButton_alt->isChecked())
        ui.pushButton_alt->setChecked(false);
    m_curModifier = Qt::NoModifier;
}

void frmKeyBoard::slotKeyNumberButtonClicked()
{
    QPushButton* pbtn = (QPushButton*)sender();
    int num = pbtn->text().toInt();
    if(isChinese){
        if(num > 0 && num < 9 && ui.listWidget->count() >= num){
        on_listWidget_itemClicked(ui.listWidget->item(num - 1));
        }
    }
    else {
    QKeyEvent keyPress(QEvent::KeyPress, num + 48, m_curModifier, pbtn->text());
    QKeyEvent keyRelease(QEvent::KeyRelease, num + 48, m_curModifier, pbtn->text());
    QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
    QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    if (ui.pushButton_ctrl->isChecked())
        ui.pushButton_ctrl->setChecked(false);
    if (ui.pushButton_win->isChecked())
        ui.pushButton_win->setChecked(false);
    if (ui.pushButton_alt->isChecked())
        ui.pushButton_alt->setChecked(false);
    }
    m_curModifier = Qt::NoModifier;
}


void frmKeyBoard::on_listWidget_itemClicked(QListWidgetItem *item)
{
    QKeyEvent keyPress(QEvent::KeyPress, 0, m_curModifier, item->text().right(1));
    QKeyEvent keyRelease(QEvent::KeyRelease, 0, m_curModifier, item->text().right(1));
    QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyPress);
    QApplication::sendEvent(qApp->focusWidget() == nullptr ? this : qApp->focusWidget(), &keyRelease);
    ui.listWidget->clear();
    m_showTextList.clear();
    m_curPage = 0;
    m_labelShowPinyin->clear();
    recordLitterBuf.clear();
}

void frmKeyBoard::on_toolButton_lastPage_clicked()
{
    if(m_curPage <= 0)
        return;
    m_curPage--;
    ui.listWidget->clear();
    for (int i = m_curPage * 9; i < m_curPage * 9 + 9; i++) {
        if(i >= m_showTextList.count())
            break;
        addOneItem(m_showTextList.at(i));
    }
}

void frmKeyBoard::on_toolButton_nextPage_clicked()
{
    if(m_curPage >= m_showTextList.count() / 9)
        return;
    m_curPage++;
    ui.listWidget->clear();
    for (int i = m_curPage * 9; i < m_curPage * 9 + 9; i++) {
        if(i >= m_showTextList.count())
            break;
        addOneItem(m_showTextList.at(i));
    }
}

八、使用示例

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    this->setWindowTitle("屏幕键盘测试（源客V）");
    QHBoxLayout* layout = new QHBoxLayout();
    layout->setContentsMargins(0, 0, 0, 0);
    layout->addWidget(ui->pushButton, 0, Qt::AlignRight);
    ui->lineEdit->setLayout(layout);
}

MainWindow::~MainWindow()
{
    delete ui;
}


void MainWindow::on_pushButton_clicked()
{
    frmKeyBoard* keyBoard = new frmKeyBoard();
    keyBoard->show();
}