拖拽事件流程

  1. mousePressEvent 鼠标按下
  2. mouseMoveEvent 鼠标开始移动（接下来换成dragMoveEvent）
  3. dragEnterEvent 开始拖拽
  4. dragMoveEvent
  5. dragMoveEvent
  6. …(重复)
  7. dragMoveEvent
  8. dragMoveEvent
  9. dropEvent 鼠标松开的时候触发（拖到外面不会触发）

拖拽没有 mouseReleaseEvent，只在点击时有

如果拖到 QListView 的底部空白，根据点获取到的索引是 -1

头文件

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#ifndef DRAG_TABLE_H
#define DRAG_TABLE_H
 
#include <QTableWidget>
#include <QListWidget>
#include <QtGui>
#include <QDrag>
 
class DragListWidget : public QListWidget
{
public:
	DragListWidget(QWidget *parent = 0);
protected:
	void mousePressEvent(QMouseEvent *event);
	void mouseMoveEvent(QMouseEvent *event);
	void dragEnterEvent(QDragEnterEvent *event);
	void dragMoveEvent(QDragMoveEvent *event);
	void dropEvent(QDropEvent *event);
public:
	QPoint startPos;
	QPoint endPos;
};
 
#endif

源文件

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#include "DragTable.h"
 
DragListWidget::DragListWidget(QWidget *parent):QListWidget(parent)
{
	this->setCurrentRow(10);
	addItem("1");
	addItem("2");
	addItem("3");
	addItem("4");
	addItem("5");
	addItem("6");
	addItem("7");
	addItem("8");
	addItem("9");
	addItem("10");
	this->setAcceptDrops(true);//设置QListWidget的Item项可以被拖拽
}
 
void DragListWidget::mousePressEvent( QMouseEvent *event )
{
	if (event->button() == Qt::LeftButton)
		startPos = event->pos();
	QListWidget::mousePressEvent(event);
}
 
void DragListWidget::mouseMoveEvent(QMouseEvent *event)
{
	QListWidgetItem *item = currentItem();
	mimeData = new QMimeData;
	mimeData->setText(item->text());
	QDrag *drag = new QDrag(this);
	drag->setMimeData(mimeData);
	//drag->setPixmap(pixmap);	
	Qt::DropAction dropAction = drag->exec(Qt::CopyAction | Qt::MoveAction, Qt::CopyAction);
	if(dropAction == Qt::MoveAction)
	{
		delete item;//删除原有的item,在dropEvent(QDropEvent *event)函数中插入item
	}
}
 
void DragListWidget::mouseReleaseEvent(QMouseEvent *event)
{
	int distance = (endPos - startPos).manhattanLength();
	if (distance >= QApplication::startDragDistance())
	{
		startDrag();
	}
}
 
void DragListWidget::dragEnterEvent( QDragEnterEvent *event )
{
	DragListWidget *source = (DragListWidget *)((void*)(event->source()));
	if (source && source == this) {
		event->setDropAction(Qt::MoveAction);
		event->accept();
	}
}
 
void DragListWidget::dragMoveEvent( QDragMoveEvent *event )
{
	DragListWidget *source = (DragListWidget *)((void*)(event->source()));
	if (source && source == this) {
		event->setDropAction(Qt::MoveAction);
		event->accept();
	}
}
 
void DragListWidget::dropEvent( QDropEvent *event )
{
	DragListWidget *source = (DragListWidget *)((void*)(event->source()));
	if (source && source == this) 
	{
		endPos = event->pos();//得到鼠标移动到的坐标
		QListWidgetItem *itemRow = itemAt(endPos);.//通过endPos获取鼠标位置所在的行
		int rowCount = row(itemRow);
		insertItem(rowCount + 1,mimeData->text());//row+1 为鼠标所指向的行，如果只是向末尾位置插入，把insertItem(rowCount + 1,mimeData->text())改为addItem(mimeData->text())
		event->setDropAction(Qt::MoveAction);
		event->accept();
	}
}

博客来源：https://blog.csdn.net/yueye30121/article/details/12508675