問題描述

我在 Qt 程序中遇到了將按鈕信號連接到插槽的困難.我的代碼是:

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();
}

程序輸出如下:

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

代碼看起來是正確的，沒有編譯器警告.運行時只是這個輸出.但看起來我正確地連接了信號和插槽.

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

推薦答案

將 Q_OBJECT 添加到您的班級，如下所示:

Add Q_OBJECT to your class, like this:

class MainWidget : public QWidget
{
    Q_OBJECT

您還必須運行 moc 以生成一些幫助程序代碼.qmake 會自動為您執行此操作，但如果您自己編譯，則需要運行 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.

這篇關于C++ Qt 信號和插槽不觸發的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！