qt 拖拽 实例 pixmap QPushButton失败

#include "treewidget.h" #include <QTreeWidgetItem> #include <QMouseEvent> #include <QtGui> TreeWidget::TreeWidget(QWidget *parent) : QTreeWidget(parent) { this->setColumnCount(1); QTreeWidgetItem *item = new QTreeWidgetItem(); item->setText(0,tr("ButtonControl")); //按钮控件 this->addTopLevelItem(item); setAcceptDrops(true); } void TreeWidget::mousePressEvent(QMouseEvent *event) { if (event->button() == Qt::LeftButton)//如果时鼠标左键 startPos = event->pos(); //记录鼠标左键位置 QTreeWidget::mousePressEvent(event); } void TreeWidget::mouseMoveEvent(QMouseEvent *event) { if (event->buttons() & Qt::LeftButton) {//如果是鼠标左键 int distance = (event->pos() - startPos).manhattanLength(); if (distance >= QApplication::startDragDistance()) performDrag(); } QTreeWidget::mouseMoveEvent(event); } void TreeWidget::dragEnterEvent(QDragEnterEvent *event) { TreeWidget *source = qobject_cast<TreeWidget *>(event->source()); if (source && source != this) { event->setDropAction(Qt::MoveAction); event->accept(); } } void TreeWidget::dragMoveEvent(QDragMoveEvent *event) { TreeWidget *source = qobject_cast<TreeWidget *>(event->source()); if (source && source != this) { event->setDropAction(Qt::MoveAction); event->accept(); } } void TreeWidget::dropEvent(QDropEvent *event) { TreeWidget *source = qobject_cast<TreeWidget *>(event->source()); if (source && source != this) { QTreeWidgetItem *item = new QTreeWidgetItem(); item->setText(0,event->mimeData()->text()); this->addTopLevelItem(item); event->setDropAction(Qt::MoveAction); event->accept(); } } void TreeWidget::performDrag() { QTreeWidgetItem *item = currentItem(); if (item) { QMimeData *mimeData = new QMimeData; QString strText = item->text(0); mimeData->setText(strText); QDrag *drag = new QDrag(this); drag->setMimeData(mimeData); QString strImage = QString(":/images/%1.png").arg(strText.toLower()); drag->setPixmap(QPixmap(strImage)); drag->exec(Qt::MoveAction); } }