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void QDragDrop::mousePressEvent(QMouseEvent *event)
{
__super::mousePressEvent(event);
mStartPoint = event->pos();//起点
}
void QDragDrop::mouseMoveEvent(QMouseEvent *event)
{
__super::mouseMoveEvent(event);
if ((event->pos() - mStartPoint).manhattanLength() > QApplication::startDragDistance())//判断是否执行拖动
{
QDrag *drag = new QDrag(this);
QMimeData *mimeData = new QMimeData;
QByteArray byteArray;//存储数据
QDataStream stream(&byteArray,QIODevice::WriteOnly);//流，写数据
stream << QImage("C:\\Users\\dlp\\Desktop\\2.png");//读取一个图片的数据
mimeData->setData("MyImage", byteArray);//设置数据
drag->setMimeData(mimeData);//设置数据
drag->exec(Qt::MoveAction);//执行拖动
delete drag;
}
}上述示例，读取了一个图片的数据保存在QMimeData里面，作为要传递的数据。并且设置了自定义格式"MyImage"。
#ifndef QDRAGDROP_H
#define QDRAGDROP_H
#include <QtWidgets/QWidget>
#include <QMouseEvent>
#include <QHBoxLayout>
class QDragDrop : public QWidget
{
Q_OBJECT
public:
QDragDrop(QWidget *parent = 0);
~QDragDrop();
protected:
void dragEnterEvent(QDragEnterEvent *event);
void dragMoveEvent(QDragMoveEvent *event);
void dropEvent(QDropEvent *event);
void mousePressEvent(QMouseEvent *event);
void mouseMoveEvent(QMouseEvent *event);
private:
QPoint mStartPoint;
QHBoxLayout *m_HBox;
};
#endif // QDRAGDROP_H
#include "qdragdrop.h"
#include <QApplication>
#include <QDrag>
#include <QMimeData>
#include <QLabel>
QDragDrop::QDragDrop(QWidget *parent)
: QWidget(parent)
{
mStartPoint = QPoint(0, 0);
m_HBox = new QHBoxLayout(this);
setAcceptDrops(true);
setWindowTitle("QWidget");
}
QDragDrop::~QDragDrop()
{
}
void QDragDrop::mousePressEvent(QMouseEvent *event)
{
__super::mousePressEvent(event);
mStartPoint = event->pos();//起点
}
void QDragDrop::mouseMoveEvent(QMouseEvent *event)
{
__super::mouseMoveEvent(event);
if ((event->pos() - mStartPoint).manhattanLength() > QApplication::startDragDistance())//判断是否执行拖动
{
QDrag *drag = new QDrag(this);
QMimeData *mimeData = new QMimeData;
QByteArray byteArray;//存储数据
QDataStream stream(&byteArray,QIODevice::WriteOnly);//流，写数据
stream << QImage("C:\\Users\\dlp\\Desktop\\2.png");//读取一个图片的数据
mimeData->setData("MyImage", byteArray);//设置数据
drag->setMimeData(mimeData);//设置数据
drag->exec(Qt::MoveAction);//执行拖动
delete drag;
}
}
void QDragDrop::dragEnterEvent(QDragEnterEvent *event)
{
__super::dragEnterEvent(event);
if (event->mimeData()->hasFormat("MyImage"))
event->acceptProposedAction();
}
void QDragDrop::dragMoveEvent(QDragMoveEvent *event)
{
__super::dragMoveEvent(event);
if (event->mimeData()->hasFormat("MyImage"))
event->acceptProposedAction();
}
void QDragDrop::dropEvent(QDropEvent *event)
{
__super::dropEvent(event);
if (event->mimeData()->hasFormat("MyImage"))
{
QByteArray byteArray = event->mimeData()->data("MyImage");//取数据
QDataStream stream(&byteArray, QIODevice::ReadOnly);//流，读数据
QImage image;
stream >> image;
QLabel *pLabel = new QLabel(this);
pLabel->setPixmap(QPixmap::fromImage(image));
m_HBox->addWidget(pLabel);
}
}
#ifndef QSHOWIMAGE_H
#define QSHOWIMAGE_H
#include <QWidget>
#include <QHBoxLayout>
#include <QDragEnterEvent>
#include <QMimeData>
class QShowImage : public QWidget
{
Q_OBJECT
public:
QShowImage(QWidget *parent = 0);
~QShowImage();
protected:
void dragEnterEvent(QDragEnterEvent *event);
void dropEvent(QDropEvent *event);
private:
QHBoxLayout *mLayout;
};
#endif // QSHOWIMAGE_H
#include "QShowImage.h"
#include <QLabel>
#include <QDebug>
QShowImage::QShowImage(QWidget *parent)
: QWidget(parent)
{
mLayout = new QHBoxLayout(this);
setAcceptDrops(true);
setWindowTitle("ShowImage");
}
QShowImage::~QShowImage()
{
}
void QShowImage::dragEnterEvent(QDragEnterEvent *event)
{
__super::dragEnterEvent(event);
if (event->mimeData()->hasUrls())
event->acceptProposedAction();
}
void QShowImage::dropEvent(QDropEvent *event)
{
__super::dropEvent(event);
if (event->mimeData()->hasUrls())
{
QList<QUrl> urls = event->mimeData()->urls();
for each (QUrl url in urls)
{
QLabel *pLabel = new QLabel(this);
QImage image(url.toString().mid(8));
pLabel->setPixmap(QPixmap::fromImage(image));
mLayout->addWidget(pLabel);
}
}
}
QListWidget qlistWidget;
QStringList strList = { "Item1", "Item2", "Item3", "Item4", "Item5" };
qlistWidget.addItems(strList);
qlistWidget.setViewMode(QListView::IconMode);
qlistWidget.setDragEnabled(true);
qlistWidget.show();但是上述只是移动了位置，Item的具体索引并没有发生改变。而且如果我们需要实现其他拖放功能，并不能满足我们的需求。那么我们就需要重新实现拖放事件，来自定义我们自己需要实现的功能。我实现了如何拖动Item，然后再添加一个Item的功能，两个QListWidgetItem并没有什么关联，只是为了展示如何实现。
#ifndef LISTWIDGET_H
#define LISTWIDGET_H
#include <QListWidget>
#include <QMouseEvent>
class ListWidget : public QListWidget
{
Q_OBJECT
public:
ListWidget(QWidget *parent = 0);
~ListWidget();
void dragEnterEvent(QDragEnterEvent *event);
void dragMoveEvent(QDragMoveEvent *event);
void dropEvent(QDropEvent *event);
private:
};
#endif // LISTWIDGET_H
#include "ListWidget.h"
#include <QDrag>
#include <QMimeData>
#include <QLabel>
ListWidget::ListWidget(QWidget *parent)
: QListWidget(parent)
{
QStringList strList = { "Item1", "Item2", "Item3", "Item4", "Item5" };
addItems(strList);
setViewMode(QListView::IconMode);
setDragEnabled(true);
setWindowTitle("QListWidget");
}
ListWidget::~ListWidget()
{
}
void ListWidget::dragEnterEvent(QDragEnterEvent *event)
{
__super::dragEnterEvent(event);
ListWidget *pList = qobject_cast<ListWidget *>(event->source());//拖动的源对象
if (pList && pList == this)
{
event->setDropAction(Qt::DropAction::CopyAction);//设置拖动动作，影响鼠标光标
event->accept();
}
}
void ListWidget::dragMoveEvent(QDragMoveEvent *event)
{
__super::dragMoveEvent(event);
ListWidget *pList = qobject_cast<ListWidget *>(event->source());//拖动的源对象
if (pList && pList == this)
{
event->setDropAction(Qt::DropAction::CopyAction);//设置拖动动作，影响鼠标光标
event->accept();
}
}
void ListWidget::dropEvent(QDropEvent *event)
{
__super::dropEvent(event);
ListWidget *pList = qobject_cast<ListWidget *>(event->source());//拖动的源对象
if (pList && pList == this)
{
QListWidgetItem *pItem = new QListWidgetItem(this);//执行释放后，要做的事情
pItem->setText(QString("Item").append(QString::number(count())));
addItem(pItem);
}
}标签：
原文地址：http://blog.csdn.net/u011417605/article/details/51316037
