.h檔案 

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QPushButton>
#include <QFrame>
#include <QSplitter>
#include <QMouseEvent>
#include <QTableWidget>
namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
    void setBtnPos();
    void setBtnIcon();


private:
    Ui::MainWindow *ui;
    //QPushButton *pushButton;
    QFrame *m_Rframe;
    QTableWidget  *m_Lframe;

    QSplitter *m_sp;
    QPushButton *m_pButton;
    bool m_bInitShow;
    QList<qint32> base;//左右佈局的寬度



protected:
    void showEvent(QShowEvent *event);
    void resizeEvent(QResizeEvent *event);
    void mouseMoveEvent(QMouseEvent *event);

private slots:
    void sl_splitterMoved(int pos, int index);
    void sl_btnClicked();
};

#endif // MAINWINDOW_H
 

.cpp檔案

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <stdio.h>
#include <QDesktopWidget>

#include <QPalette>
#include <QDebug>
#include <QList>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow), m_bInitShow(false)
{
    ui->setupUi(this);


//    m_Lframe = new QFrame;
//    m_Rframe = new QFrame;
//    m_sp     = new QSplitter(this);
    m_Lframe = ui->tableWidget;
    m_Rframe=ui->frame;
    m_sp= ui->splitter;


    m_pButton= new QPushButton(this); // after Splitter
    setBtnPos();

//    m_sp->addWidget(ui->tableWidget);
//    m_sp->addWidget(m_Rframe);

    connect(m_sp,SIGNAL(splitterMoved(int,int)),this,SLOT(sl_splitterMoved(int,int)));
    connect(m_pButton,SIGNAL(clicked()),this,SLOT(sl_btnClicked()));

//    setCentralWidget(m_sp);
    //setWindowFlags(Qt::FramelessWindowHint);

    m_Lframe->setMouseTracking(true);
    m_Rframe->setMouseTracking(true);
    m_sp->setMouseTracking(true);
    m_pButton->setMouseTracking(true);
    setMouseTracking(true);

}



MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::setBtnPos()//把Button移動到分割線中間位置
{
    int width=m_Lframe->width()-m_pButton->width();
    int heigh=(m_Lframe->height()-m_pButton->height())/2;
    m_pButton->move(width,heigh);
}

void MainWindow::setBtnIcon()//選擇button圖片
{
    if(m_Rframe->width()!=0)
    {
        m_pButton->setIcon(QIcon(":/png/image/quit.png"));
    }
    else
    {
        m_pButton->setIcon(QIcon(":/png/image/update.png"));
    }
}

void MainWindow::showEvent(QShowEvent *event)
{

    if(!m_bInitShow)
    {

        m_bInitShow=true;

        QPalette p2=m_Rframe->palette(); // initial the frame back round
        p2.setColor(QPalette::Window,Qt::gray);
        p2.setColor(QPalette::WindowText,Qt::red);
        m_Rframe->setPalette(p2);
        m_Rframe->setAutoFillBackground(true);
        m_Rframe->setMaximumWidth(300);

        base= m_sp->sizes();

        m_pButton->setFixedSize(32,32);
        m_pButton->setIconSize(QSize(16,16));
        m_pButton->setVisible(true);
        m_pButton->setStyleSheet("border:none;");
        setBtnPos();  //設定button位置
        setBtnIcon(); //顯示對應圖片
    }

    QMainWindow::showEvent(event);

}
void MainWindow::resizeEvent(QResizeEvent *event)
{
    setBtnPos();
    QMainWindow::resizeEvent(event);
}

void MainWindow::sl_splitterMoved(int pos,int index)
{

    setBtnPos();
    if(m_Rframe->width()==0)
    {
        setBtnIcon();
    }
}


void MainWindow::sl_btnClicked()//設定左右佈局的寬度
{
    // static  QList<qint32> base= m_sp->sizes(); //keep the initial pos
    QList<qint32>  newSize;

    if(m_Rframe->width()!=0)
    {
        newSize<<base.at(0)+base.at(1)<<0;
    }
    else
    {
        newSize<<base.at(0)<<base.at(1);
    }
    m_sp->setSizes(newSize);  //move the SPLITTER

    setBtnPos();
    setBtnIcon();

}

void MainWindow::mouseMoveEvent(QMouseEvent *event)
{

    int isWidth  = m_pButton->pos().x()+m_pButton->width();
    int isHeight = m_pButton->pos().y()+m_pButton->height();

    int x=event->pos().x();
    int y=event->pos().y();

    if(x>m_pButton->pos().x()&&x<isWidth&&y>m_pButton->y()&&y<isHeight)
    {
        m_pButton->setVisible(true);
    }

    else
    {
        m_pButton->setVisible(true);
    }


}