C++ Qt 信号和插槽不触发

2021-12-09 00:00:00 qt qt-signals c++

我在 Qt 程序中遇到了将按钮信号连接到插槽的困难.我的代码是:

I am having difficulty in my Qt program with connecting button signals to my slots. My code is:

Main.cpp

#include <QtGui/QApplication>
#include "MainWidget.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    MainWidget mainWidget;
    mainWidget.show();

    return app.exec();
}

MainWidget.h

MainWidget.h

#ifndef MAINWIDGET_H
#define MAINWIDGET_H

#include <QWidget>

class MainWidget : public QWidget
{
public:
    MainWidget();

public slots:
    void bAdvice_clicked();
    void bWeather_clicked();
    void bNextMeeting_clicked();
    void bQuit_clicked();
};

#endif // MAINWIDGET_H

MainWidget.cpp

MainWidget.cpp

#include "MainWidget.h"
#include <QMessageBox>
#include <QPushButton>
#include <QTextEdit>
#include <QVBoxLayout>

MainWidget::MainWidget()
{
    QLayout *layout = new QVBoxLayout();
    this->setLayout(layout);

    QTextEdit *message = new QTextEdit();
    layout->addWidget(message);

    QPushButton *bAdvice = new QPushButton("Advice");
    connect(bAdvice, SIGNAL(clicked()), this, SLOT(bAdvice_clicked()));
    layout->addWidget(bAdvice);

    QPushButton *bWeather = new QPushButton("Weather");
    connect(bWeather, SIGNAL(clicked()), this, SLOT(bWeather_clicked()));
    layout->addWidget(bWeather);

    QPushButton *bNextMeeting = new QPushButton("Next Meeting");
    connect(bNextMeeting, SIGNAL(clicked()), this, SLOT(bNextMeeting_clicked()));
    layout->addWidget(bNextMeeting);

    QPushButton *bQuit = new QPushButton("Quit");
    connect(bQuit, SIGNAL(clicked()), this, SLOT(bQuit_clicked()));
    layout->addWidget(bQuit);
}

void MainWidget::bAdvice_clicked()
{
}

void MainWidget::bWeather_clicked()
{
}

void MainWidget::bNextMeeting_clicked()
{
    QMessageBox::information(this, "Next Meeting", "Today", QMessageBox::Ok);
}

void MainWidget::bQuit_clicked()
{
    this->close();
}

程序输出如下:

Starting C:UsersSameerDocumentsPartAQuestion2debugPartAQuestion2.exe...
Object::connect: No such slot QWidget::bAdvice_clicked() in MainWidget.cpp:16
Object::connect: No such slot QWidget::bWeather_clicked() in MainWidget.cpp:20
Object::connect: No such slot QWidget::bNextMeeting_clicked() in MainWidget.cpp:24
Object::connect: No such slot QWidget::bQuit_clicked() in MainWidget.cpp:28

C:UsersSameerDocumentsPartAQuestion2debugPartAQuestion2.exe exited with code 0

代码看起来是正确的，没有编译器警告.运行时只是这个输出.但看起来我正确地连接了信号和插槽.

The code seems right, no compiler warnings. Just this output at runtime. But it looks like I hooked the signals and slots up correctly.

推荐答案

将 Q_OBJECT 添加到您的班级，如下所示:

Add Q_OBJECT to your class, like this:

class MainWidget : public QWidget
{
    Q_OBJECT

您还必须运行 moc 以生成一些帮助程序代码.qmake 会自动为您执行此操作，但如果您自己编译，则需要运行 moc.

You also have to run moc to generate some helper code. qmake does that automatically for your, but if you compile this yourself, you need to run moc.

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