本次学习了拖放文件相关内容，是紧接着上一篇文章的，这次学习主要参考了博文：跟我一起学QT7:拖放文件,地址：https://my.oschina.net/voler/blog/345722

//dialog.h
#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <QListWidget>
#include <QPushButton>
#include <QVBoxLayout>
#include <QHBoxLayout>

namespace Ui {
class Dialog;
}

class Dialog : public QDialog
{
    Q_OBJECT

public:
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();

public slots:
    void AToB_clicked();
    void BToA_clicked();

private:
    void moveCurrentItem(QListWidget *source,
                         QListWidget *target);

private:
    QListWidget *listA;
    QListWidget *listB;
    QPushButton *buttonAToB;
    QPushButton *buttonBToA;
};

#endif // DIALOG_H

//dialo.cpp
#include "dialog.h"

Dialog::Dialog(QWidget *parent) :
    QDialog(parent)
{

    listA = new QListWidget;
    listB = new QListWidget;
    buttonAToB = new QPushButton("->");
    buttonBToA = new QPushButton("<-");

    listA->addItem("Giosue Carducci");
    listA->addItem("Eyvind Johnson");
    listA->addItem("Sally Prudhomme");
    listA->addItem("Henryk Sienkiewicz");
    listA->addItem("Carl Spitteler");
    listA->addItem("Rabindranath Tagore");
    listA->addItem("Kawabata Yasunari");

    listB->addItem("Rudolf Eucken");
    listB->addItem("Anatole France");
    listB->addItem("Rudyard Kipling");
    listB->addItem("Thomas Mann");
    listB->addItem("Eugene O'Neill");
    listB->addItem("Sigrid Undset");


    buttonAToB->setText("->");
    buttonBToA->setText("<-");

    QVBoxLayout *buttonLayout = new QVBoxLayout;
    buttonLayout->addWidget(buttonAToB);
    buttonLayout->addWidget(buttonBToA);

    QHBoxLayout *hboxLayout = new QHBoxLayout;
    hboxLayout->addWidget(listA);
    hboxLayout->addLayout(buttonLayout);
    hboxLayout->addWidget(listB);
    setLayout(hboxLayout);

    //设置窗口的固定高度和宽度
    setFixedHeight( sizeHint().height() );

    connect(buttonAToB, SIGNAL(clicked()),
            this, SLOT(AToB_clicked()));
    connect(buttonBToA, SIGNAL(clicked()),
            this, SLOT(BToA_clicked()));
}

Dialog::~Dialog()
{

}

//把数据移到右边窗口
void Dialog::AToB_clicked()
{
    moveCurrentItem(listA, listB);
}

//把数据移到左边窗口
void Dialog::BToA_clicked()
{
    moveCurrentItem(listB, listA);
}

void Dialog::moveCurrentItem(QListWidget *source,
                     QListWidget *target)
{
    if (source->currentItem()) {
        QListWidgetItem *newItem = source->currentItem()->clone();
        target->addItem(newItem);
        target->setCurrentItem(newItem);
        delete source->currentItem();
    }
}

//main.cpp
#include "dialog.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Dialog w;
    w.show();
    return a.exec();
}