Qt - 锁屏界面加虚拟小键盘

一、实现效果

鼠标点击“密码输入栏”，弹出虚拟键盘，输入锁屏密码后，点击虚拟键盘外部区域，则会隐藏虚拟键盘，再点击登录，成功进入主界面。

二、虚拟键盘-程序设计

2.1 frmNum.h

#ifndef FRMNUM_H
#define FRMNUM_H

#include <QWidget>
#include <QLineEdit>
#include <QPushButton>
#include <QTimer>

namespace Ui
{
    class frmNum;
}

class frmNum : public QWidget
{
    Q_OBJECT

public:
    explicit frmNum(QWidget *parent =nullptr);
    ~frmNum();

    //单例模式,保证一个程序只存在一个输入法实例对象
    static frmNum *Instance()
    {
        if (!_instance)
        {
            _instance = new frmNum;
        }
        return _instance;
    }

    void Init(QString style, int fontSize);  //初始化窗口,包括字体大小

protected:
    //事件过滤器：处理鼠标按下弹出小键盘
    bool eventFilter(QObject *obj, QEvent *event);

private slots:
    //焦点改变事件槽函数处理
    void focusChanged(QWidget *oldWidget, QWidget *nowWidget);
    //小键盘按键处理槽函数
    void btn_clicked();
    //改变小键盘样式
    void changeStyle(QString topColor, QString bottomColor,
                     QString borderColor, QString textColor);
    //定时器处理退格键
    void reClicked();

private:
    Ui::frmNum *ui;

    static frmNum *_instance;       //实例对象

    bool isPressBackBtn;            //是否长按退格键
    bool isFirst;                   //是否首次加载

    QPushButton *btnPress;          //长按按钮
    QTimer *backBtnTimert;          //退格键定时器
    QWidget *currentWidget;         //当前焦点的对象
    QLineEdit *currentLineEdit;     //当前焦点的单行文本框

    QString currentEditType;        //当前焦点控件的类型
    QString currentStyle;           //当前小键盘样式
    int currentFontSize;            //当前输入法面板字体大小

    bool checkPress();              //校验当前长按的按钮//初始化属性
    void ChangeStyle(QString currentStyle);             //改变样式

    void insertValue(QString value);//插入值到当前焦点控件
    void deleteValue();             //删除当前焦点控件的一个字符
    void clearValue();             //clear当前焦点控件的一个字符
};

#endif // FRMNUM_H

上面是“虚拟键盘程序”的头文件，这里使用了单例模式，保证一个程序只存在一个输入法实例对象。

2.2 frmNum.cpp

#include "frmnum.h"
#include "ui_frmnum.h"
#include <QShortcut>
#include <QDebug>

frmNum *frmNum::_instance = nullptr;

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

    //初始化窗口
    Init("black",20); //黑色，字体大小为20px

    ui->btnClear->setFocus();
    ui->btnClear->setShortcut(QKeySequence::InsertParagraphSeparator);
    ui->btnClear->setShortcut(Qt::Key_Enter);
    ui->btnClear->setShortcut(Qt::Key_Return);
}

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

//初始化窗口,包括字体大小
void frmNum::Init(QString style, int fontSize)
{
    //设置窗口无边框且窗口显示在最顶层
    this->setWindowFlags(Qt::FramelessWindowHint | Qt::Tool | Qt::WindowStaysOnTopHint);

    isFirst = true; //是否首次加载
    isPressBackBtn = false; //是否长按退格键
    //退格键定时器
    backBtnTimert = new QTimer(this);
    connect(backBtnTimert, SIGNAL(timeout()), this, SLOT(reClicked()));
    currentWidget = nullptr;//当前焦点的对象

    //输入法面板字体大小,如果需要更改面板字体大小,该这里即可
    this->currentFontSize = fontSize;

    //如果需要更改输入法面板的样式,改变style这个形式参数即可
    //blue--淡蓝色  dev--dev风格  black--黑色  brown--灰黑色  lightgray--浅灰色  darkgray--深灰色  gray--灰色  silvery--银色
    this->ChangeStyle(style);

    //初始化小键盘上各按键属性
    ui->btn0->setProperty("btnNum", true);
    ui->btn1->setProperty("btnNum", true);
    ui->btn2->setProperty("btnNum", true);
    ui->btn3->setProperty("btnNum", true);
    ui->btn4->setProperty("btnNum", true);
    ui->btn5->setProperty("btnNum", true);
    ui->btn6->setProperty("btnNum", true);
    ui->btn7->setProperty("btnNum", true);
    ui->btn8->setProperty("btnNum", true);
    ui->btn9->setProperty("btnNum", true);
    ui->btnDelete->setProperty("btnOther", true);

    //链接小键盘上各数字键与功能键的点击信号到点击槽函数上
    QList<QPushButton *> btn = this->findChildren<QPushButton *>();
    foreach (QPushButton * b, btn)
    {
        connect(b, SIGNAL(clicked()), this, SLOT(btn_clicked()));
    }

    //绑定全局改变焦点信号槽
    connect(qApp, SIGNAL(focusChanged(QWidget *, QWidget *)),
            this, SLOT(focusChanged(QWidget *, QWidget *)));

    //绑定按键事件过滤器
    qApp->installEventFilter(this);
}

void frmNum::focusChanged(QWidget *oldWidget, QWidget *nowWidget)
{
    //qDebug() << "oldWidget:" << oldWidget << " nowWidget:" << nowWidget;
    if (nowWidget != nullptr && !this->isAncestorOf(nowWidget))
    {
        /*在Qt5和linux系统中(嵌入式linux除外),当输入法面板关闭时,焦点会变成无,然后焦点会再次移到焦点控件处
        这样导致输入法面板的关闭按钮不起作用,关闭后马上有控件获取焦点又显示.
        为此,增加判断,当焦点是从有对象转为无对象再转为有对象时不要显示.
        这里又要多一个判断,万一首个窗体的第一个焦点就是落在可输入的对象中,则要过滤掉*/

        #ifndef __arm__
                if (oldWidget == nullptr && !isFirst)
                {
                    return;
                }
        #endif

        isFirst = false;
        if (nowWidget->inherits("QLineEdit"))
        {
            currentLineEdit = static_cast<QLineEdit *>(nowWidget);
            currentEditType = "QLineEdit";
            this->setVisible(true);
        }
        else
        {
            currentWidget = nullptr;
            currentLineEdit = nullptr;
            currentEditType = "";
            this->setVisible(false);
        }

        QRect rect = nowWidget->rect();
        QPoint pos = QPoint(rect.left(), rect.bottom() + 2);
        pos = nowWidget->mapToGlobal(pos);
        this->setGeometry(pos.x(), pos.y(), this->width(), this->height());
    }

    Q_UNUSED(oldWidget);//未使用参数
}

//事件过滤器：处理鼠标按下弹出小键盘
bool frmNum::eventFilter(QObject *obj, QEvent *event)
{
    if (event->type() == QEvent::MouseButtonPress)
    {
        //确保每次点击输入栏都弹出虚拟键盘
        if (currentEditType == "QLineEdit")
        {
            if (obj != ui->btnClear)
            {
                this->setVisible(true);
            }
            btnPress = static_cast<QPushButton *>(obj);

            if (checkPress())
            {
                isPressBackBtn = true;
                backBtnTimert->start(500);
            }
        }

        return false;
    }
    else if (event->type() == QEvent::MouseButtonRelease)
    {
        btnPress = static_cast<QPushButton *>(obj);

        if (checkPress())
        {
            isPressBackBtn = false;
            backBtnTimert->stop();
        }

        return false;
    }

    return QWidget::eventFilter(obj, event);
}

//校验当前长按的按钮
bool frmNum::checkPress()
{
    //只有属于数字键盘的合法按钮才继续处理
    bool num_ok = btnPress->property("btnNum").toBool();
    bool other_ok = btnPress->property("btnOther").toBool();
    if (num_ok || other_ok)
    {
        return true;
    }

    return false;
}

//定时器处理退格键
void frmNum::reClicked()
{
    if (isPressBackBtn)
    {
        backBtnTimert->setInterval(30);
        btnPress->click();
    }
}

//小键盘按键处理槽函数
void frmNum::btn_clicked()
{
    //如果当前焦点控件类型为空,则返回不需要继续处理
    if (currentEditType == "")
    {
        return;
    }

    QPushButton *btn = static_cast<QPushButton *>(sender());
    QString objectName = btn->objectName();
    if (objectName == "btnDelete")
    {
        this->deleteValue();
    }
    else if (objectName == "btnClear")
    {
        this->clearValue();
    }
    else
    {
        QString value = btn->text();
        this->insertValue(value);
    }
}

//插入值到当前焦点控件
void frmNum::insertValue(QString value)
{
    if (currentEditType == "QLineEdit")
    {
        currentLineEdit->insert(value);
    }
}

//删除当前焦点控件的一个字符
void frmNum::deleteValue()
{
    if (currentEditType == "QLineEdit")
    {
        currentLineEdit->backspace();
    }
}

//清空当前焦点控件的所有字符
void frmNum::clearValue()
{
    if (currentEditType == "QLineEdit")
    {
        currentLineEdit->clear();
    }
}

//改变样式
void frmNum::ChangeStyle(QString currentStyle)
{
    if (currentStyle == "blue")
    {
        changeStyle("#DEF0FE", "#C0DEF6", "#C0DCF2", "#386487");
    }
    else if (currentStyle == "dev")
    {
        changeStyle("#C0D3EB", "#BCCFE7", "#B4C2D7", "#324C6C");
    }
    else if (currentStyle == "gray")
    {
        changeStyle("#E4E4E4", "#A2A2A2", "#A9A9A9", "#000000");
    }
    else if (currentStyle == "lightgray")
    {
        changeStyle("#EEEEEE", "#E5E5E5", "#D4D0C8", "#6F6F6F");
    }
    else if (currentStyle == "darkgray")
    {
        changeStyle("#D8D9DE", "#C8C8D0", "#A9ACB5", "#5D5C6C");
    }
    else if (currentStyle == "black")
    {
        changeStyle("#4D4D4D", "#292929", "#D9D9D9", "#CACAD0");
    }
    else if (currentStyle == "brown")
    {
        changeStyle("#667481", "#566373", "#C2CCD8", "#E7ECF0");
    }
    else if (currentStyle == "silvery")
    {
        changeStyle("#E1E4E6", "#CCD3D9", "#B2B6B9", "#000000");
    }
}

//改变小键盘样式
void frmNum::changeStyle(QString topColor, QString bottomColor, QString borderColor, QString textColor)
{
    QStringList qss;
    qss.append(QString("QWidget#frmNum{background:qlineargradient(spread:pad,x1:0,y1:0,x2:0,y2:1,stop:0 %1,stop:1 %2);}")
               .arg(topColor).arg(bottomColor));
    qss.append("QPushButton{padding:5px;border-radius:3px;}");
    qss.append(QString("QPushButton:hover{background:qlineargradient(spread:pad,x1:0,y1:0,x2:0,y2:1,stop:0 %1,stop:1 %2);}")
               .arg(topColor).arg(bottomColor));
    qss.append(QString("QLabel,QPushButton{font-size:%1pt;color:%2;}")
               .arg(currentFontSize).arg(textColor));
    qss.append(QString("QPushButton#btnPre,QPushButton#btnNext,QPushButton#btnClose{padding:5px;}"));
    qss.append(QString("QPushButton{border:1px solid %1;}")
               .arg(borderColor));
    qss.append(QString("QLineEdit{border:1px solid %1;border-radius:5px;padding:2px;background:none;selection-background-color:%2;selection-color:%3;}")
               .arg(borderColor).arg(bottomColor).arg(topColor));
    this->setStyleSheet(qss.join(""));
}

上面是“虚拟键盘程序”的源代码，当检测焦点在 QlineEdit 单行输入栏上，则显示虚拟键盘，否则隐藏虚拟键盘。虚拟键盘调出的显示位置跟 QlineEdit 对齐，尝试过但还是无法改变显示位置。另外可以对上面代码进行扩展，扩展支持 QTextEdit、QTextBrowser 等窗口部件。

2.3 frmNum.ui

三、锁屏界面-程序设计

3.1 lockWin.h

/*
注：注意.ui文件中的dailog的focusPolicy要设置为clickFocus
*/
#ifndef LOCKWIN_H
#define LOCKWIN_H

#include <QDialog>
#include <QDebug>
#include "frmnum.h"

#define PASSWD "123456" //锁屏密码

namespace Ui {
class LoginWin;
}

class LockWin : public QDialog
{
    Q_OBJECT

public:
    explicit LockWin(QWidget *parent = nullptr);
    ~LockWin();

private slots:
    void on_cancelButton_clicked(); //取消按钮-点击槽函数：清空密码栏
    void on_loginButton_clicked(); //登录按钮-点击槽函数

private:
    Ui::LoginWin *ui;

    bool eventFilter(QObject *watched, QEvent *event); //事件过滤器

    frmNum *myFrmnum;
};

#endif // LOCKWIN_H

上面是“锁屏界面程序”的头文件，这里定义了一个“虚拟键盘”类对象指针，锁屏密码设置为“123456”。

3.2 lockWin.cpp

#include "lockWin.h"
#include "ui_loginwin.h"

LockWin::LockWin(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::LoginWin)
{
    ui->setupUi(this);

    //设置窗口无边框且窗口显示在最顶层
    this->setWindowFlags(Qt::FramelessWindowHint | Qt::Tool | Qt::WindowStaysOnTopHint);  
        
    //阻塞其父子窗口
    this->setWindowModality(Qt::WindowModal);

    ui->lineEdit->installEventFilter(this);

    //通过正则表达式设置"密码输入栏"，只能输入数字0-9,不超过6位
    QValidator *accountValidator = new QRegExpValidator(QRegExp("[0-9]{6}"));
    ui->lineEdit->setValidator(accountValidator);

    myFrmnum = new frmNum(this);
}

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

//事件过滤器
bool  LockWin::eventFilter(QObject *watched, QEvent *event)
{
    if(watched ==ui->lineEdit)
    {
        if(QEvent::FocusIn == event->type())
        {
            if(ui->lineEdit->echoMode()==QLineEdit::Normal)
            {
                ui->lineEdit->clear();
            }

            ui->lineEdit->setEchoMode(QLineEdit::Password);
        }
    }

    // 最后将事件交给上层对话框
    return QWidget::eventFilter(watched,event);
}

//---------------------------slots-----------------------------------------------

//取消按钮-点击槽函数：清空密码栏
void LockWin::on_cancelButton_clicked()
{
    ui->lineEdit->clear();
}

//登录按钮-点击槽函数
void LockWin::on_loginButton_clicked()
{
    if(ui->lineEdit->text()==PASSWD) //密码正确则关闭锁屏窗口
    {
        this->close();
    }
    else if(ui->lineEdit->text().isEmpty())
    {
        ui->infoLabel->setText("输入密码不能为空！");
    }
    else if(ui->lineEdit->text().length()<6)
    {
        ui->infoLabel->setText("输入密码不足6位！");
        ui->lineEdit->clear();
    }
    else
    {
        ui->infoLabel->setText("密码错误，请重新输入");
        ui->lineEdit->clear();
    }
}

上面是“锁屏界面程序”的源文件，这里使用了this->setWindowModality(Qt::WindowModal)来成为模态对话框阻塞主界面，即锁屏界面关闭才能进入主界面。