QObject::connect: 没有这样的信号progressbarV::keyReleaseEvent()

Posted 2023-02-17

【中文标题】QObject::connect: 没有这样的信号progressbarV::keyReleaseEvent()

【英文标题】：QObject::connect: No such signal progressbarV::keyReleaseEvent()

【发布时间】：2016-04-12 19:06:14

【问题描述】：

我正在尝试创建一个项目，其中我有一个创建 QProgressBar 的 progressbarV 类。我在我的主窗口中调用这个类。我的目标是当我点击进度条时导航到另一个屏幕。为此，我尝试实现 KeyRleaseEvent，但无论我做什么，我都会不断收到错误“QObject::connect: No such signal progressbarV::keyReleaseEvent()”。非常感谢我能得到解决此问题的任何帮助。

Please find my code below:-

mainwindow.h
    #ifndef MAINWINDOW_H
    #define MAINWINDOW_H

    #include <QMainWindow>
    #include <QWidget>
    #include <QProgressBar>
    #include <QLabel>
    #include <QPixmap>
    #include <QPushButton>
    #include <QtWidgets>
    #include <QProcess>

    #include "headerfiles/progressbarV.h"
    #include "headerfiles/redzonesettingsscreen.h"

    class progressbarH;

    class redZoneSettingsScreen;

    class MainWindow : public QMainWindow//,public QProcess
    
        Q_OBJECT

    private:
        progressbarV *progressbar_V_left;

    public:
        MainWindow();
        ~MainWindow();

        void GetObjects(redZoneSettingsScreen *);

    private slots:
        void handleSettingsButtonPressed();

    /*protected:
        virtual void keyReleaseEvent(QKeyEvent *); //Q_DECL_OVERRIDE;*/
    ;

    #endif // MAINWINDOW_H

mainwindow.cpp

    #include "headerfiles/mainwindow.h"

    redZoneSettingsScreen *gotoSettingsScreen;

    MainWindow::MainWindow()
    
        progressbar_V_left = new progressbarV;
        progressbar_V_left->setParent(this);
        progressbar_V_left->setGeometry(350,200,90,450);
        progressbar_V_left->setTitle("Height");
        progressbar_V_left->setData(labelCurHeight->getDataValue());
        progressbar_V_left->setMinVal(0);
        progressbar_V_left->setMaxVal(labelMaxHeight->getDataValue());
        connect(progressbar_V_left, SIGNAL (keyReleaseEvent()), this, SLOT 
            (handleSettingsButtonPressed()));
    

    MainWindow::~MainWindow()
    
        delete progressbar_V_left;
    

    void MainWindow::GetObjects(redZoneSettingsScreen *button)
    
        gotoSettingsScreen = button;
    

    void MainWindow::handleSettingsButtonPressed()
    
        gotoSettingsScreen->hide();
        gotoSettingsScreen->show();
        this->hide();
    

    /*void MainWindow::keyReleaseEvent(QKeyEvent *event)
    

    */

progressbarV.h

    #ifndef PROGRESSBARV_H
    #define PROGRESSBARV_H

    #include <QWidget>
    #include <QProgressBar>
    #include <QLabel>
    #include <QPixmap>

    class progressbarV: public QWidget
    
        Q_OBJECT

    private:
        QProgressBar *progressbar_V;
        QLabel *labelRedDanger, *labelYellowWarning;
        float maxScaledHeight, redZoneScaledHeight, yellowZoneScaledHeight;

        int spn, spn_value;
        QString title;
        int data;
        short minVal;
        short maxVal;

    public:
        progressbarV();
        ~progressbarV();

        void setSPN(int);
        int getSPN();

        void setSPN_Value(int);
        int getSPN_Value();

        void setTitle(QString);
        QString getTitle();

        void setData(int);
        int getData();

        void setMinVal(short);
        short getMinVal();

        void setMaxVal(short);
        short getMaxVal();

        /*void setLowError(short);
        short getLowError();

        void setLowWarning(short);
        short getLowWarning();

        void setHighError(short);
        short getHighError();

        void setHighWarning(short);
        short getHighWarning();*/

        QProgressBar* getProgressBarV();

    protected:
        void keyReleaseEvent(QKeyEvent *); //Q_DECL_OVERRIDE;

    ;
   #endif // PROGRESSBARH_H

progressbarV.cpp

    #include "headerfiles/progressbarV.h"

    progressbarV::progressbarV()
    
        progressbar_V = new QProgressBar;
        progressbar_V->setParent(this);
        progressbar_V->setStyleSheet("QProgressBar border: solid grey; border-
            width: 6; border-radius: 12; text-align: center;,    
        QProgressBar::chunkbackground-color: limegreen; width: 0px; margin: 
            0px;");
        progressbar_V->setGeometry(2,0,50,200);
        progressbar_V->setOrientation(Qt::Vertical);

        maxScaledHeight = (200*100)/120;
        redZoneScaledHeight = 200 - ((maxScaledHeight*105)/100);
        yellowZoneScaledHeight = 200 - ((maxScaledHeight*90)/100);

        QPixmap mypixRed(":/images/images/redZone.png");
        labelRedDanger = new QLabel;
        labelRedDanger->setParent(this);
        labelRedDanger->setGeometry(8,redZoneScaledHeight,38,3);
        labelRedDanger->setPixmap(mypixRed);

        QPixmap mypixYellow(":/images/images/yellowZone.png");
        labelYellowWarning = new QLabel;
        labelYellowWarning->setParent(this);
        labelYellowWarning->setGeometry(8,yellowZoneScaledHeight,38,3);
        labelYellowWarning->setPixmap(mypixYellow);
    

    progressbarV::~progressbarV()
    
        delete progressbar_V;
        delete labelRedDanger;
        delete labelYellowWarning;
    

    void progressbarV::setSPN(int val)
    
        spn = val;
    

    int progressbarV::getSPN()
    
        return spn;
    

    void progressbarV::setSPN_Value(int val)
    
        spn_value = val;
    

    int progressbarV::getSPN_Value()
    
        return spn_value;
    

    void progressbarV::setTitle(QString mTitle)
    
        title = mTitle;
    

    QString progressbarV::getTitle()
    
        return title;
    

    void progressbarV::setData(int mData)
    
        data = mData;
        progressbar_V->setValue(data);
    

    int progressbarV::getData()
    
        return data;
    

    void progressbarV::setMinVal(short mMinVal)
    
        minVal = mMinVal;
        progressbar_V->setMinimum(minVal);
    

    short progressbarV::getMinVal()
    
        return minVal;
    

    void progressbarV::setMaxVal(short mMaxVal)
    
        maxVal = mMaxVal;
        progressbar_V->setMaximum(maxVal);
    

    short progressbarV::getMaxVal()
    
        return maxVal;
    

    QProgressBar *progressbarV::getProgressBarV()
    
        return progressbar_V;
    

    void progressbarV::keyReleaseEvent(QKeyEvent *event)
    

    

Since I am new to QT, kindly give me solutions in the form of code snippets

Thanks in advance,
Sam

【问题讨论】：

connect 命令只接受信号作为参数。 keyReleaseEvent 不是信号。

我将如何创建信号？

您可以创建一个处理 keyReleaseEvent 的函数，在该函数中调用您自己的信号。查找用于定义信号的示例代码。

【参考方案1】：

您需要将keyReleaseEvent 声明为公共SLOT

public slots:
    void keyReleaseEvent(QKeyEvent *); //Q_DECL_OVERRIDE;

以便 QT 可以使用旧的连接方式连接到它。