Qt4.8.2 QPushButton按钮贴图以及实现按钮的几种常用状态

一、继承自QPushButton，不改变图片本身，而是通过改变按钮背景的透明度

myPushButton.h

#ifndef MYPUSHBUTTON_H
#define MYPUSHBUTTON_H

#include <QPushButton>

class myPushButton : public QPushButton
{
Q_OBJECT
public:
explicit myPushButton(QWidget *parent = 0);
explicit myPushButton(QString iconStr,QWidget *parent=0);

signals:

public slots:

private:
void setBkPalette(int transparency);//设置透明度
protected:
void enterEvent(QEvent *);//鼠标进入事件
void leaveEvent(QEvent *);//离开
void mousePressEvent(QMouseEvent *e);//点击
void mouseReleaseEvent(QMouseEvent *e);//释放
};

#endif // MYPUSHBUTTON_H


myPushButton.cpp
#include "mypushbutton.h"
#include <QPalette>
#include <QPixmap>

myPushButton::myPushButton(QWidget *parent) :
QPushButton(parent)
{
}
myPushButton::myPushButton(QString iconStr, QWidget *parent):QPushButton(parent)
{
QPixmap pixmap(iconStr);
setIcon(QIcon(pixmap));
setIconSize(pixmap.size());
setBkPalette(0);//设置背景完全透明
setFlat(true);
setAutoFillBackground(true);
}

void myPushButton::setBkPalette(int transparency)//设置背景透明度
{
QPalette palette;
palette.setBrush(QPalette::Button,QBrush(QColor(255,255,255,transparency)));
setPalette(palette);
}
void myPushButton::enterEvent(QEvent *)
{
setBkPalette(120);
}
void myPushButton::leaveEvent(QEvent *)
{
setBkPalette(0);
}
void myPushButton::mousePressEvent(QMouseEvent *e)
{
setBkPalette(150);
}
void myPushButton::mouseReleaseEvent(QMouseEvent *e)
{
setBkPalette(120);
emit clicked();//必须写上，否则不会发出clicked信号
}

二、背景一直为透明色，通过鼠标事件改变按钮的贴图，需要用到事件过滤器
widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QtGui/QWidget>

class myPushButton;
class QPushButton;
class Widget : public QWidget
{
Q_OBJECT

public:
Widget(QWidget *parent = 0);
~Widget();

private:
//枚举按钮的几种状态
enum btnStatus{btnNormal,btnEnter,btnClick,btnNoStatus};

myPushButton *btn1;//通过改变背景透明度
QPushButton *btnClose;//通过改变按钮图片
btnStatus btnCloseStatus;

void drawClose();//给btnClose贴图

protected:
bool eventFilter(QObject *, QEvent *);//事件过滤器
};

#endif // WIDGET_H


widget.cpp
#include "widget.h"
#include "mypushbutton.h"
#include <QVBoxLayout>
#include <QPalette>
#include <QPushButton>
#include <QEvent>

Widget::Widget(QWidget *parent)
: QWidget(parent)
{
QPalette palette;
palette.setBrush(QPalette::Window,QBrush(QColor(202,189,52)));
setPalette(palette);

btn1=new myPushButton(":/img/btnwifi.png");
btnClose=new QPushButton;
btnClose->setStyleSheet("background:transparent;border:0px;");
btnCloseStatus=btnNoStatus;
drawClose();
//安装事件过滤器，处理鼠标的进入，离开，按下，释放的事件
btnClose->installEventFilter(this);

QVBoxLayout *mainLayout=new QVBoxLayout;
mainLayout->addWidget(btn1);
mainLayout->addWidget(btnClose);
setLayout(mainLayout);
}

Widget::~Widget()
{

}

void Widget::drawClose()
{
static QPixmap pixmap(":/img/btn_close.png");
static int width=pixmap.width()/4;
static int height=pixmap.height();
btnClose->setIcon(QIcon(pixmap.copy(btnCloseStatus*width,0,width,height)));
btnClose->setIconSize(QSize(width,height));
}
bool Widget::eventFilter(QObject *obj, QEvent *event)
{
if(obj==btnClose)
{
btnCloseStatus=btnNoStatus;
if(event->type()==QEvent::Enter)
btnCloseStatus=btnEnter;
else if(event->type()==QEvent::Leave)
btnCloseStatus=btnNormal;
else if(event->type()==QEvent::MouseButtonPress)
btnCloseStatus=btnClick;
else if(event->type()==QEvent::MouseButtonRelease)
btnCloseStatus=btnEnter;
if(btnCloseStatus!=btnNoStatus)
drawClose();
}
return QWidget::eventFilter(obj,event);
}