qt 实现 动态 拖拽垃圾箱

#include "widget.h" #include <QApplication> #include <QListWidget> #include <QPropertyAnimation> #include <QVBoxLayout> #include <QPushButton> #include <QBitmap> #include <QPainter> #include <QResizeEvent> #include <QDebug> Widget::Widget(QWidget *parent) : QWidget(parent) { QVBoxLayout *lay = new QVBoxLayout(this); listWidget = new QListWidget; listWidget->setViewMode(QListWidget::IconMode); listWidget->addItem(new QListWidgetItem(QIcon(":/img/test.png"),QStringLiteral("test"))); listWidget->addItem(new QListWidgetItem(QIcon(":/img/trash.png"),QStringLiteral("trash"))); listWidget->installEventFilter(this); lay->addWidget(listWidget); reRect = new QLabel(this); reRect->setAutoFillBackground(true); QPalette pal = reRect->palette(); pal.setBrush(QPalette::Background,Qt::lightGray); reRect->setPalette(pal); QPixmap pix(":/img/trash.png"); reRect->resize(width(),pix.height() + 20); reRect->setMinimumHeight(pix.height() + 20); reLabel = new QLabel; reLabel->resize(pix.size()); reLabel->setPixmap(pix); reLabel->setMask(pix.mask()); reLabel->setAcceptDrops(true); reLabel->installEventFilter(this); QHBoxLayout *hlay = new QHBoxLayout(reRect); hlay->addWidget(reLabel,0,Qt::AlignCenter); ani = new QPropertyAnimation(reRect, "geometry"); ani->setEasingCurve(QEasingCurve::InCurve); ani->setDuration(150); connect(ani,&QPropertyAnimation::finished,[&]{ani->setDirection(QAbstractAnimation::Direction(!ani->direction()));}); } void Widget::resizeEvent(QResizeEvent *event) { reRect->resize(event->size().width(),reRect->height()); if(initFlag){ initFlag = false; reRect->move(reRect->x(),-reRect->height()); } ani->setStartValue(QRect(reRect->x(),-reRect->height(),reRect->width(),reRect->height())); ani->setEndValue(reRect->rect()); return QWidget::resizeEvent(event); } Widget::~Widget() { } bool Widget::eventFilter(QObject *watched, QEvent *event) { if(reLabel = qobject_cast<QLabel*>(watched)){ if(event->type() == QEvent::DragEnter){ QDragEnterEvent *drageEnterE{nullptr}; try{ drageEnterE = dynamic_cast<QDragEnterEvent*>(event); }catch(std::bad_cast &e){ qDebug() << e.what(); } if(drageEnterE){ trashPainted = false; drageEnterE->acceptProposedAction(); } return true; }else if(event->type() == QEvent::Drop){ QDropEvent *dropE{nullptr}; try{ dropE = dynamic_cast<QDropEvent*>(event); }catch(std::bad_cast &e){ qDebug() << e.what(); } if(dropE){ listWidget->takeItem(listWidget->row(listWidget->currentItem())); QPixmap *pix = const_cast<QPixmap*>(reLabel->pixmap()); *pix = QPixmap(":/img/trash.png"); reLabel->repaint(); } return true; }else if(event->type() == QEvent::DragMove){ QDragMoveEvent *mvEvent{nullptr}; try{ mvEvent = dynamic_cast<QDragMoveEvent*>(event); }catch(std::bad_cast &e){ qDebug() << e.what(); } if(mvEvent && !trashPainted){ QPixmap *pix = const_cast<QPixmap*>(reLabel->pixmap()); QPainter p(pix); p.initFrom(pix); p.fillRect(pix->rect(),QColor(200,0,0,50)); reLabel->repaint(); trashPainted = !trashPainted; } return true; }else if(event->type() == QEvent::DragLeave){ QDragLeaveEvent *leEvent{nullptr}; try{ leEvent = dynamic_cast<QDragLeaveEvent*>(event); }catch(std::bad_cast &e){ qDebug() << e.what(); } if(leEvent){ QPixmap *pix = const_cast<QPixmap*>(reLabel->pixmap()); *pix = QPixmap(":/img/trash.png"); reLabel->repaint(); } return true; } }else if(listWidget == qobject_cast<QListWidget*>(watched)){ QChildEvent *childEvent{nullptr}; switch (event->type()) { case QEvent::ChildAdded: try{ childEvent = dynamic_cast<QChildEvent*>(event); }catch(std::bad_cast &e){ qDebug() << e.what(); } if(childEvent){ ani->start(); } break; case QEvent::ChildRemoved: try{ childEvent = dynamic_cast<QChildEvent*>(event); }catch(std::bad_cast &e){ qDebug() << e.what(); } if(childEvent){ ani->start(); } break; } } return QWidget::eventFilter(watched,event); }