Qt 5 设计师 QObject::connect: No such slot QDialog答案

【问题标题】：Qt 5 designer QObject::connect: No such slot QDialogQt 5 设计师 QObject::connect: No such slot QDialog
【发布时间】：2016-10-01 15:19:43
【问题描述】：

我在 Designer 中创建了连接，然后尝试更改插槽的功能。然后我声明该私有插槽，然后对其进行初始化，并在构建程序运行但连接不起作用之后。它说QObject::connect: No such slot QDialog

我认为问题可能出在 Qt 自动生成的 ui_dl.h 中 dl.h

#ifndef DL_H
#define DL_H
#include <QDialog>


namespace Ui {
class Dl;
}

class Dl : public QDialog
{
    Q_OBJECT

public:
    explicit Dl(QWidget *parent = 0);
    ~Dl();

private:
    Ui::Dl *ui;
private slots:
     void print_shit();
};
#endif

dl.cpp

#include "dl.h"
#include "ui_dl.h"
#include <iostream>


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

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

void Dl::print_shit(){

}

main.cpp

#include <QApplication>
#include <QQmlApplicationEngine>
#include "ui_dl.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    Ui_Dl * dialog = new Ui_Dl;
    QDialog *wnd = new QDialog();

    dialog->setupUi(wnd);
    wnd->show();

    return app.exec();
}


#ifndef UI_DL_H
#define UI_DL_H

#include <QtCore/QVariant>
#include <QtWidgets/QAction>
#include <QtWidgets/QApplication>
#include <QtWidgets/QButtonGroup>
#include <QtWidgets/QDialog>
#include <QtWidgets/QGridLayout>
#include <QtWidgets/QHBoxLayout>
#include <QtWidgets/QHeaderView>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QSlider>
#include <QtWidgets/QSpinBox>
#include <QtWidgets/QWidget>

QT_BEGIN_NAMESPACE

class Ui_Dl
{
public:
    QWidget *layoutWidget;
    QGridLayout *gridLayout;
    QHBoxLayout *horizontalLayout_2;
    QPushButton *pushButton_6;
    QPushButton *knopka;
    QHBoxLayout *horizontalLayout;
    QPushButton *pushButton;
    QPushButton *pushButton_2;
    QPushButton *pushButton_3;
    QHBoxLayout *horizontalLayout_3;
    QPushButton *pushButton_8;
    QPushButton *pushButton_7;
    QPushButton *pushButton_9;
    QSpinBox *spinBox;
    QSlider *horizontalSlider;

    void setupUi(QDialog *Dl)
    {
        if (Dl->objectName().isEmpty())
            Dl->setObjectName(QStringLiteral("Dl"));
        Dl->setWindowModality(Qt::NonModal);
        Dl->resize(705, 504);
        QSizePolicy sizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
        sizePolicy.setHorizontalStretch(0);
        sizePolicy.setVerticalStretch(0);
        sizePolicy.setHeightForWidth(Dl->sizePolicy().hasHeightForWidth());
        Dl->setSizePolicy(sizePolicy);
        QPalette palette;
        QBrush brush(QColor(0, 0, 0, 255));
        brush.setStyle(Qt::SolidPattern);
        palette.setBrush(QPalette::Active, QPalette::WindowText, brush);
        QBrush brush1(QColor(153, 240, 185, 255));
        brush1.setStyle(Qt::SolidPattern);
        palette.setBrush(QPalette::Active, QPalette::Button, brush1);
        QBrush brush2(QColor(255, 255, 255, 255));
        brush2.setStyle(Qt::SolidPattern);
        palette.setBrush(QPalette::Active, QPalette::Light, brush2);
        QBrush brush3(QColor(204, 247, 220, 255));
        brush3.setStyle(Qt::SolidPattern);
        palette.setBrush(QPalette::Active, QPalette::Midlight, brush3);
        QBrush brush4(QColor(76, 120, 92, 255));
        brush4.setStyle(Qt::SolidPattern);
        palette.setBrush(QPalette::Active, QPalette::Dark, brush4);
        QBrush brush5(QColor(102, 160, 123, 255));
        brush5.setStyle(Qt::SolidPattern);
        palette.setBrush(QPalette::Active, QPalette::Mid, brush5);
        palette.setBrush(QPalette::Active, QPalette::Text, brush);
        palette.setBrush(QPalette::Active, QPalette::BrightText, brush2);
        palette.setBrush(QPalette::Active, QPalette::ButtonText, brush);
        palette.setBrush(QPalette::Active, QPalette::Base, brush2);
        palette.setBrush(QPalette::Active, QPalette::Window, brush1);
        palette.setBrush(QPalette::Active, QPalette::Shadow, brush);
        palette.setBrush(QPalette::Active, QPalette::AlternateBase, brush3);
        QBrush brush6(QColor(255, 255, 220, 255));
        brush6.setStyle(Qt::SolidPattern);
        palette.setBrush(QPalette::Active, QPalette::ToolTipBase, brush6);
        palette.setBrush(QPalette::Active, QPalette::ToolTipText, brush);
        palette.setBrush(QPalette::Inactive, QPalette::WindowText, brush);
        palette.setBrush(QPalette::Inactive, QPalette::Button, brush1);
        palette.setBrush(QPalette::Inactive, QPalette::Light, brush2);
        palette.setBrush(QPalette::Inactive, QPalette::Midlight, brush3);
        palette.setBrush(QPalette::Inactive, QPalette::Dark, brush4);
        palette.setBrush(QPalette::Inactive, QPalette::Mid, brush5);
        palette.setBrush(QPalette::Inactive, QPalette::Text, brush);
        palette.setBrush(QPalette::Inactive, QPalette::BrightText, brush2);
        palette.setBrush(QPalette::Inactive, QPalette::ButtonText, brush);
        palette.setBrush(QPalette::Inactive, QPalette::Base, brush2);
        palette.setBrush(QPalette::Inactive, QPalette::Window, brush1);
        palette.setBrush(QPalette::Inactive, QPalette::Shadow, brush);
        palette.setBrush(QPalette::Inactive, QPalette::AlternateBase, brush3);
        palette.setBrush(QPalette::Inactive, QPalette::ToolTipBase, brush6);
        palette.setBrush(QPalette::Inactive, QPalette::ToolTipText, brush);
        palette.setBrush(QPalette::Disabled, QPalette::WindowText, brush4);
        palette.setBrush(QPalette::Disabled, QPalette::Button, brush1);
        palette.setBrush(QPalette::Disabled, QPalette::Light, brush2);
        palette.setBrush(QPalette::Disabled, QPalette::Midlight, brush3);
        palette.setBrush(QPalette::Disabled, QPalette::Dark, brush4);
        palette.setBrush(QPalette::Disabled, QPalette::Mid, brush5);
        palette.setBrush(QPalette::Disabled, QPalette::Text, brush4);
        palette.setBrush(QPalette::Disabled, QPalette::BrightText, brush2);
        palette.setBrush(QPalette::Disabled, QPalette::ButtonText, brush4);
        palette.setBrush(QPalette::Disabled, QPalette::Base, brush1);
        palette.setBrush(QPalette::Disabled, QPalette::Window, brush1);
        palette.setBrush(QPalette::Disabled, QPalette::Shadow, brush);
        palette.setBrush(QPalette::Disabled, QPalette::AlternateBase, brush1);
        palette.setBrush(QPalette::Disabled, QPalette::ToolTipBase, brush6);
        palette.setBrush(QPalette::Disabled, QPalette::ToolTipText, brush);
        Dl->setPalette(palette);
        Dl->setCursor(QCursor(Qt::ArrowCursor));
        Dl->setAutoFillBackground(false);
        Dl->setSizeGripEnabled(true);
        layoutWidget = new QWidget(Dl);
        layoutWidget->setObjectName(QStringLiteral("layoutWidget"));
        layoutWidget->setGeometry(QRect(140, 90, 421, 351));
        gridLayout = new QGridLayout(layoutWidget);
        gridLayout->setObjectName(QStringLiteral("gridLayout"));
        gridLayout->setContentsMargins(0, 0, 0, 0);
        horizontalLayout_2 = new QHBoxLayout();
        horizontalLayout_2->setObjectName(QStringLiteral("horizontalLayout_2"));
        horizontalLayout_2->setSizeConstraint(QLayout::SetNoConstraint);
        pushButton_6 = new QPushButton(layoutWidget);
        pushButton_6->setObjectName(QStringLiteral("pushButton_6"));
        sizePolicy.setHeightForWidth(pushButton_6->sizePolicy().hasHeightForWidth());
        pushButton_6->setSizePolicy(sizePolicy);
        pushButton_6->setMaximumSize(QSize(191, 103));
        pushButton_6->setMouseTracking(false);
        pushButton_6->setAcceptDrops(false);
        pushButton_6->setAutoFillBackground(false);
        pushButton_6->setStyleSheet(QStringLiteral("border-image: url(:/new/prefix1/lico);"));
        pushButton_6->setCheckable(false);
        pushButton_6->setAutoRepeat(false);
        pushButton_6->setAutoExclusive(false);
        pushButton_6->setAutoDefault(true);
        pushButton_6->setFlat(false);

        horizontalLayout_2->addWidget(pushButton_6);

        knopka = new QPushButton(layoutWidget);
        knopka->setObjectName(QStringLiteral("knopka"));
        knopka->setEnabled(true);
        sizePolicy.setHeightForWidth(knopka->sizePolicy().hasHeightForWidth());
        knopka->setSizePolicy(sizePolicy);
        knopka->setSizeIncrement(QSize(0, 0));
        knopka->setMouseTracking(false);
        knopka->setAutoFillBackground(false);
        knopka->setStyleSheet(QStringLiteral(""));
        knopka->setCheckable(false);
        knopka->setAutoDefault(true);
        knopka->setFlat(false);

        horizontalLayout_2->addWidget(knopka);


        gridLayout->addLayout(horizontalLayout_2, 1, 0, 1, 1);

        horizontalLayout = new QHBoxLayout();
        horizontalLayout->setObjectName(QStringLiteral("horizontalLayout"));
        horizontalLayout->setSizeConstraint(QLayout::SetNoConstraint);
        pushButton = new QPushButton(layoutWidget);
        pushButton->setObjectName(QStringLiteral("pushButton"));
        QSizePolicy sizePolicy1(QSizePolicy::Minimum, QSizePolicy::Preferred);
        sizePolicy1.setHorizontalStretch(0);
        sizePolicy1.setVerticalStretch(0);
        sizePolicy1.setHeightForWidth(pushButton->sizePolicy().hasHeightForWidth());
        pushButton->setSizePolicy(sizePolicy1);
        pushButton->setMouseTracking(false);
        pushButton->setCheckable(false);

        horizontalLayout->addWidget(pushButton);

        pushButton_2 = new QPushButton(layoutWidget);
        pushButton_2->setObjectName(QStringLiteral("pushButton_2"));
        sizePolicy1.setHeightForWidth(pushButton_2->sizePolicy().hasHeightForWidth());
        pushButton_2->setSizePolicy(sizePolicy1);
        pushButton_2->setMinimumSize(QSize(125, 104));
        pushButton_2->setMouseTracking(false);
        pushButton_2->setCheckable(false);

        horizontalLayout->addWidget(pushButton_2);

        pushButton_3 = new QPushButton(layoutWidget);
        pushButton_3->setObjectName(QStringLiteral("pushButton_3"));
        sizePolicy.setHeightForWidth(pushButton_3->sizePolicy().hasHeightForWidth());
        pushButton_3->setSizePolicy(sizePolicy);
        pushButton_3->setMouseTracking(false);
        pushButton_3->setCheckable(false);

        horizontalLayout->addWidget(pushButton_3);


        gridLayout->addLayout(horizontalLayout, 0, 0, 1, 1);

        horizontalLayout_3 = new QHBoxLayout();
        horizontalLayout_3->setObjectName(QStringLiteral("horizontalLayout_3"));
        horizontalLayout_3->setSizeConstraint(QLayout::SetNoConstraint);
        pushButton_8 = new QPushButton(layoutWidget);
        pushButton_8->setObjectName(QStringLiteral("pushButton_8"));
        sizePolicy1.setHeightForWidth(pushButton_8->sizePolicy().hasHeightForWidth());
        pushButton_8->setSizePolicy(sizePolicy1);
        pushButton_8->setMouseTracking(false);
        pushButton_8->setStyleSheet(QString::fromUtf8("border-image: url(C:/Users/Acer/Pictures/Screenshot \320\273\320\270\321\206\320\276(\320\260\320\262\320\260\321\202\320\260\321\200).png);"));
        pushButton_8->setCheckable(false);

        horizontalLayout_3->addWidget(pushButton_8);

        pushButton_7 = new QPushButton(layoutWidget);
        pushButton_7->setObjectName(QStringLiteral("pushButton_7"));
        sizePolicy1.setHeightForWidth(pushButton_7->sizePolicy().hasHeightForWidth());
        pushButton_7->setSizePolicy(sizePolicy1);
        pushButton_7->setMouseTracking(false);
        pushButton_7->setStyleSheet(QStringLiteral("border-image: url(:/new/prefix1/lico);"));
        pushButton_7->setCheckable(false);

        horizontalLayout_3->addWidget(pushButton_7);

        pushButton_9 = new QPushButton(layoutWidget);
        pushButton_9->setObjectName(QStringLiteral("pushButton_9"));
        sizePolicy.setHeightForWidth(pushButton_9->sizePolicy().hasHeightForWidth());
        pushButton_9->setSizePolicy(sizePolicy);
        pushButton_9->setMouseTracking(false);
        pushButton_9->setCheckable(false);

        horizontalLayout_3->addWidget(pushButton_9);


        gridLayout->addLayout(horizontalLayout_3, 2, 0, 1, 1);

        spinBox = new QSpinBox(Dl);
        spinBox->setObjectName(QStringLiteral("spinBox"));
        spinBox->setGeometry(QRect(590, 250, 101, 121));
        horizontalSlider = new QSlider(Dl);
        horizontalSlider->setObjectName(QStringLiteral("horizontalSlider"));
        horizontalSlider->setGeometry(QRect(470, 470, 160, 22));
        horizontalSlider->setOrientation(Qt::Horizontal);

        retranslateUi(Dl);
        QObject::connect(knopka, SIGNAL(clicked()), Dl, SLOT(print_shit()));

        QMetaObject::connectSlotsByName(Dl);
    } // setupUi

    void retranslateUi(QDialog *Dl)
    {
        Dl->setWindowTitle(QApplication::translate("Dl", "Dialog", 0));
        pushButton_6->setText(QApplication::translate("Dl", "\320\243\320\272\321\200\320\260\320\270\320\275\320\260", 0));
        knopka->setText(QApplication::translate("Dl", "\320\234\320\270\321\201\321\202\320\265\321\200 \320\264\321\203\320\264\320\265\321\206", 0));
        pushButton->setText(QApplication::translate("Dl", "\320\257 \320\265\320\261\321\203 \321\201\320\276\320\261\320\260\320\272", 0));
#ifndef QT_NO_TOOLTIP
        pushButton_2->setToolTip(QApplication::translate("Dl", "<html><head/><body><p><br/></p></body></html>", 0));
#endif // QT_NO_TOOLTIP
        pushButton_2->setText(QApplication::translate("Dl", "\320\242\321\200\320\260\320\274\320\277", 0));
        pushButton_3->setText(QApplication::translate("Dl", "\320\234\320\270\321\201\321\202\321\200\320\265 \320\264\321\203\320\264\320\265\321\206", 0));
        pushButton_8->setText(QApplication::translate("Dl", "\320\242\321\200\320\260\320\274\320\277", 0));
        pushButton_7->setText(QApplication::translate("Dl", "\320\243\320\272\321\200\320\260\320\270\320\275\320\260", 0));
        pushButton_9->setText(QApplication::translate("Dl", "\320\257 \320\265\320\261\321\203 \321\201\320\276\320\261\320\260\320\272", 0));
    } // retranslateUi

};

namespace Ui {
    class Dl: public Ui_Dl {};
} // namespace Ui

QT_END_NAMESPACE

#endif // UI_DL_H

【问题讨论】：

标签： qt5

【解决方案1】：

我看到两个可能的问题：

您将 *Dl 作为 QDialog 传递到 SetupUI：
```
void setupUi(QDialog *Dl) {
…
}
```
但是您的插槽是在您的自定义类Dl 中定义的。所以 Qt 说 QDialog 没有名为 print_shit() 的插槽。
另外，connectSlotsByName 要求您的插槽遵循某个 naming convention：

void QMetaObject::connectSlotsByName(QObject *object)

递归搜索给定对象的所有子对象，并将来自它们的匹配信号连接到遵循以下形式的对象槽：

void on_<object name>_<signal name>(<signal parameters>);

假设我们的对象有一个 QPushButton 类型的子对象，对象名称为 button1。捕捉按钮的 clicked() 信号的槽是：

void on_button1_clicked();

你的班级似乎没有这样的位置Dl。

【讨论】：