编辑:我提供了一个答案,但我很乐意接受另一个提供解释。Qt信号的继承?
我为QPushButton
添加了一些功能,但在将clicked
信号连接到一个插槽后,它不会被调用。如果我使用香草QPushButton,并且不改变其他任何东西,它就会起作用。下面的代码:
/// --- imagebutton.h
#ifndef IMAGEBUTTON_H
#define IMAGEBUTTON_H
#include <QPushButton>
#include <QImage>
enum ButtonState
{
Normal,
MouseOver,
Pushed
};
class ImageButton : public QPushButton
{
Q_OBJECT
private:
ButtonState state;
public:
QImage *NormalImage;
QImage *MouseOverImage;
QImage *PushedImage;
public:
explicit ImageButton(QWidget *parent = 0);
virtual ~ImageButton();
void enterEvent(QEvent *e);
void leaveEvent(QEvent *e);
void mousePressEvent(QMouseEvent *e);
void mouseReleaseEvent(QMouseEvent *e);
void paintEvent(QPaintEvent *e);
signals:
public slots:
};
#endif // IMAGEBUTTON_H
/// --- imagebutton.cpp
#include <QPainter>
#include "imagebutton.h"
ImageButton::ImageButton(QWidget *parent) :
QPushButton(parent)
{
state = Normal;
}
void ImageButton::enterEvent(QEvent *e)
{
QPushButton::enterEvent(e);
state = MouseOver;
this->repaint();
}
void ImageButton::leaveEvent(QEvent *e)
{
QPushButton::leaveEvent(e);
state = Normal;
this->repaint();
}
void ImageButton::mousePressEvent(QMouseEvent *e)
{
QPushButton::mousePressEvent(e);
state = Pushed;
this->repaint();
}
void ImageButton::mouseReleaseEvent(QMouseEvent *e)
{
QPushButton::mousePressEvent(e);
state = MouseOver;
this->repaint();
}
void ImageButton::paintEvent(QPaintEvent *e)
{
QPainter painter(this);
QImage *pic = NULL;
switch (state)
{
case Normal:
pic = NormalImage;
break;
case MouseOver:
pic = MouseOverImage;
break;
case Pushed:
pic = PushedImage;
break;
default:
pic = NormalImage;
break;
}
painter.drawImage(0, 0, *pic);
}
ImageButton::~ImageButton()
{
delete NormalImage;
delete MouseOverImage;
delete PushedImage;
}
这就是我如何连接信号:
void MainWindow::initInterface()
{
ImageButton *btn_start = new ImageButton(ui->page);
btn_start->setText("start");
connect(btn_start, SIGNAL(clicked()), this, SLOT(btn_clicked()));
// more buttons connected to the same slot
}
什么可能是这里的问题?
连接是否返回true或false?如果它是错误的控制台输出是什么?它应该打印一些调试信息,如果它是一个调试版本。 – 2010-07-31 14:52:20
它返回true,并且没有输出(尽管它是一个调试版本)。 – 2010-07-31 14:58:19