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);
}