QT鼠标拖拽的实现及源码

#include "MyDragWidget.h" #include "ui_MyDragWidget.h" #include <QMouseEvent> #include <QDragEnterEvent> #include <QDebug> #include <QLabel> #include <QMimeData> #include <QDrag> #include <QPainter> MyDragWidget::MyDragWidget(QWidget *parent) : QWidget(parent), ui(new Ui::MyDragWidget) { ui->setupUi(this); //setMinimumSize(200, 200); setAcceptDrops(true);///允许拖动事件 ///创建4个lable存放图片 QLabel* lable1 = new QLabel(this); lable1->setPixmap(QPixmap(":png/1.png")); lable1->move(0,0);///放在指定位置 QLabel* lable12 = new QLabel(this); lable12->setPixmap(QPixmap(":png/01.png")); lable12->move(100,0); QLabel* lable13 = new QLabel(this); lable13->setPixmap(QPixmap(":png/12.png")); lable13->move(100,100); QLabel* lable14 = new QLabel(this); lable14->setPixmap(QPixmap(":png/13.png")); lable14->move(100,100); } void MyDragWidget::setName(QString name) { m_name = name; } MyDragWidget::~MyDragWidget() { delete ui; } void MyDragWidget::dragEnterEvent(QDragEnterEvent *event) { qDebug()<<"4"<<m_name; if (event->mimeData()->hasFormat("application/x-dnditemdata")) { if (event->source() == this) { event->setDropAction(Qt::MoveAction); event->accept(); } else { event->acceptProposedAction(); } } else { event->ignore(); } } void MyDragWidget::dragMoveEvent(QDragMoveEvent *event) { qDebug()<<"3"<<m_name; if (event->mimeData()->hasFormat("application/x-dnditemdata")) { if (event->source() == this) { event->setDropAction(Qt::MoveAction); event->accept(); } else { event->acceptProposedAction(); } } else { event->ignore(); } } void MyDragWidget::dropEvent(QDropEvent *event)///落下创建Qlabel { qDebug()<<"2"<<m_name; if (event->mimeData()->hasFormat("application/x-dnditemdata")) { QByteArray itemData = event->mimeData()->data("application/x-dnditemdata"); QDataStream dataStream(&itemData, QIODevice::ReadOnly); QPixmap pixmap; QPoint offset; dataStream >> pixmap >> offset; QLabel *newIcon = new QLabel(this); newIcon->setPixmap(pixmap); newIcon->move(event->pos() - offset); newIcon->show(); newIcon->setAttribute(Qt::WA_DeleteOnClose); if (event->source() == this) { event->setDropAction(Qt::MoveAction); event->accept(); } else { event->acceptProposedAction(); } } else { event->ignore(); } } //! [1] void MyDragWidget::mousePressEvent(QMouseEvent *event) { qDebug()<<"1"<<m_name; QLabel *child = static_cast<QLabel*>(childAt(event->pos()));///获取带你给前点击的子控件 Qlabel if (!child) return; QPixmap pixmap = *child->pixmap(); ///图像处理类 QByteArray itemData; QDataStream dataStream(&itemData, QIODevice::WriteOnly); dataStream << pixmap << QPoint(event->pos() - child->pos());///添加光标位置、和鼠标位置 //! [1] //! [2] QMimeData *mimeData = new QMimeData; mimeData->setData("application/x-dnditemdata", itemData); //! [2] //! [3] QDrag *drag = new QDrag(this); ///鼠标拖拽事件 drag->setMimeData(mimeData); ///设置选择节点信息等 drag->setPixmap(pixmap); ///设置鼠标移动时的样式 drag->setHotSpot(event->pos() - child->pos()); //! [3] QPixmap tempPixmap = pixmap; QPainter painter; painter.begin(&tempPixmap); painter.fillRect(pixmap.rect(), QColor(127, 127, 127, 127)); painter.end(); child->setPixmap(tempPixmap); if (drag->exec(Qt::CopyAction | Qt::MoveAction, Qt::CopyAction) == Qt::MoveAction) { child->close(); } else { child->show(); child->setPixmap(pixmap); } }