QT - 多个定义

Question

i can't compile this QT program because I get this message about "multiple definition of `Dialog::status(QString const&)'"

There is some code: Dialog hader:

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>

//class QCheckBox;
class QLabel;
class QLineEdit;
class QPushButton;

class Dialog : public QDialog
{
    Q_OBJECT

public:
    Dialog(QWidget *parent = 0);
signals:
    void status(const QString &str);
private slots:
    void on();
private:
    QLabel *label;
    QLineEdit *LineEdit;
    QPushButton *button;
};

#endif // DIALOG_H

and implementation file:

#include <QLabel>
#include <QLineEdit>
#include <QPushButton>
#include <QHBoxLayout>

#include "dialog.h"

Dialog::Dialog(QWidget *parent) : QDialog(parent)
{
    label = new QLabel("Ne label");
    LineEdit = new QLineEdit();
    button = new QPushButton("Push me");

    QHBoxLayout *layout = new QHBoxLayout();
    layout->addWidget(label);
    layout->addWidget(LineEdit);
    layout->addWidget(button);
    setLayout(layout);
    setWindowTitle("Dialog name");

    connect(button, SIGNAL(clicked()), this, SLOT(on()));
}

void Dialog::on()
{
    label->setStyleSheet("QLabel { background-color : black; color : white; }");
}

void Dialog::status(const QString &str)
{

}

project file looks fine:

QT += gui declarative
SOURCES += \
main.cpp \
dialog.cpp
HEADERS += \
dialog.h

Thanks for your help.

Answer 1

You declare the status function as a signal and then implement a body for it. Signals are just that, a signal and do not have an implementation.

Depending upon your intent, you need to either remove the body implementation for the status function, or move the declaration to being a slot, not a signal.