问题描述
Following my previous post我一直在尝试使用QGraphicsView
解决定位问题。
将小部件从QListWidget
拖放到QGraphicsView
内后,它会跳转到任何地方。
问题,我也在其他用户的帮助下尝试解决以下问题:
将小部件拖到QGraphicsView
内并放下。它只是在随机位置出现,必须注意检索它。此行为对用户不友好,有时需要花费一些时间才能找到小部件。
代码下方:
scene.h
#ifndef SCENE_H
#define SCENE_H
#include <QGraphicsScene>
class Scene : public QGraphicsScene
{
public:
Scene(QObject *parent = nullptr);
protected:
void dragenterEvent(QGraphicsSceneDragDropEvent *event);
void dragMoveEvent(QGraphicsSceneDragDropEvent *event);
void dropEvent(QGraphicsSceneDragDropEvent *event);
};
#endif // SCENE_H
scene.cpp
void Scene::dropEvent(QGraphicsSceneDragDropEvent *event)
{
QByteArray encoded =
event->mimeData()->data("application/x-qabstractitemmodeldatalist");
QDataStream stream(&encoded,qiodevice::ReadOnly);
QStringList rosTables;
QString newString;
while (!stream.atEnd()) {
int row,col;
QMap<int,QVariant> roleDataMap;
stream >> row >> col >> roleDataMap;
rosTables << roleDataMap[Qt::displayRole].toString();
}
for (const QString &tableType : rosTables) {
if (tableType == "Images") {
QPoint initPos(0,0);
auto *wgt = new CustomTableWidget;
auto *proxyControl = addRect(0,QPen(Qt::black),QBrush(Qt::darkGreen));
auto *sizegrip = new QSizegrip(wgt);
auto *layout = new QHBoxLayout(wgt);
layout->setContentsMargins(0,0);
layout->addWidget(sizegrip,Qt::AlignRight | Qt::AlignBottom);
connect(wgt,&CustomTableWidget::sizeChanged,[wgt,proxyControl](){
proxyControl->setRect(wgt->geometry().adjusted(-10,-10,10,10));
});
wgt->setColumnCount(2);
wgt->setRowCount(2);
for (int ridx = 0; ridx < wgt->rowCount(); ridx++) {
for (int cidx = 0; cidx < wgt->columnCount(); cidx++) {
auto *item = new QTableWidgetItem();
item->setText(QString("%1").arg(ridx));
wgt->setItem(ridx,cidx,item);
}
}
auto *const proxy = addWidget(wgt);
proxy->setPos(initPos.x(),initPos.y()
+ proxyControl->rect().height());
proxy->setParentItem(proxyControl);
proxyControl->setPos(initPos.x(),initPos.y());
proxyControl->setFlag(QGraphicsItem::ItemIsMovable,true);
proxyControl->setFlag(QGraphicsItem::ItemIsSelectable,true);
proxyControl->setRect(wgt->geometry().adjusted(-10,10));
}
}
}
迄今为止已尝试解决的问题:
现在QGraphicsScene
已被子类化以重写鼠标事件,尤其是在这种情况下,注意dropEvent(QGraphicsSceneDragDropEvent *event)
是因为它是“查看窗口小部件”的负责功能。 / p>
for (const QString &tableType : rosTables) {
if (tableType == "Images") {
QPoint initPos(event->scenePos()); // <-- Tried this but no change
auto *wgt = new CustomTableWidget;
auto *proxyControl = addRect(0,QBrush(Qt::darkGreen));
auto *sizegrip = new QSizegrip(wgt);
auto *layout = new QHBoxLayout(wgt);
}
尝试进行的另一件事是提供QPoint
和event->scenePos().toPoint()
,以达到目标,但不幸的是,这也不能解决问题:
for (const QString &tableType : rosTables) {
if (tableType == "Images") {
QPoint initPos(event->scenePos().toPoint()); // <-- Tried this too but no change
auto *wgt = new CustomTableWidget;
auto *proxyControl = addRect(0,QBrush(Qt::darkGreen));
auto *sizegrip = new QSizegrip(wgt);
auto *layout = new QHBoxLayout(wgt);
}
如果有人对问题可能有什么想法,请提供如何解决问题的指导。
解决方法
-
将
proxy->setPos(initPos.x(),initPos.y() + proxyControl->rect().height());
更改为proxy->setPos(10,10);
。 -
设置场景矩形:
Scene::Scene(QObject *parent) : QGraphicsScene(parent) { setBackgroundBrush(Qt::lightGray); setSceneRect(0,1000,1000); }
-
设置视图对齐方式,例如在 MainWindow.cpp 中:
ui->graphicsView->setAlignment(Qt::AlignLeft | Qt::AlignTop);