1.相关说明

重写resizeEvent(这个按需重写)、dragEnterEvent(拖拽事件函数)、dropEvent(放下事件函数)，可以将本地图片拖拽到label标签中

2.相关界面

 

3.相关代码

#include "widget.h"
#include "ui_widget.h"
#include <QDragEnterEvent>
#include <QMimeData>
#include <QFileInfo>Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);setAcceptDrops(true);ui->plainTextEdit->setAcceptDrops(false);ui->label->setAcceptDrops(false);ui->label->setScaledContents(true);
}Widget::~Widget()
{delete ui;
}void Widget::resizeEvent(QResizeEvent *event)
{QSize sz = ui->plainTextEdit->size();ui->plainTextEdit->move(5, 5);ui->label->move(5, sz.height()+10);ui->plainTextEdit->resize(this->width()-10, sz.height());ui->label->resize(this->width()-10, this->height()-sz.height()-20);event->accept();
}void Widget::dropEvent(QDropEvent *event)
{QString fullPath = event->mimeData()->urls().at(0).path();fullPath = fullPath.right(fullPath.length()-1);QPixmap pixmap(fullPath);ui->label->setPixmap(pixmap);event->accept();
}void Widget::dragEnterEvent(QDragEnterEvent *event)
{ui->plainTextEdit->clear();ui->plainTextEdit->appendPlainText("dragEvent事件，mimeData的format:");for(auto &item : event->mimeData()->formats()){ui->plainTextEdit->appendPlainText(item);}ui->plainTextEdit->appendPlainText("dragEvent事件，mimeData的urls:");for(auto &item : event->mimeData()->urls()){ui->plainTextEdit->appendPlainText(item.path());}if(event->mimeData()->hasUrls()){QString filename = event->mimeData()->urls().at(0).fileName();QFileInfo fileInfo(filename);QString ex = fileInfo.suffix().toUpper();if(ex == "JPG"){event->acceptProposedAction();} else {event->ignore();}} else {event->ignore();}
}