Question

我正在制作一个使用QTableWidget的项目。当我试图让它接受滴剂时，我开始知道它不像我想的那样表现。问题是，如果我将QTableWidget更改为QWidget，那么drop就被接受了。所以，问题不在于编码。这里是代码，至于我关注的问题是在“MyDropWidget”类

中

#include <QMouseEvent>
#include <QWidget>
#include <QMessageBox>
#include <math.h>
#include <QApplication>
#include <QPainter>
#include <sstream>
#include <QDragEnterEvent>
#include <QDropEvent>
#include <QLabel>
#include <QPaintEvent>
#include <QTableWidget>
#define RADIUS 2
#define DISTANCE_BETWEEN_OBJECTS 2
#define DASH_RECT_HALF_WIDTH 2
#include <QHeaderView>
#include <QPainter>
#include <QHBoxLayout>
#include <QWidget>
#include <QApplication>

class MyMessageBox:public QMessageBox
{
public:
    MyMessageBox(std::string message,QWidget *parent=0):QMessageBox(QMessageBox::NoIcon,QString("ErrorMessage"),QString(message.c_str()),QMessageBox::Ok,parent,Qt::Widget)
    {
    }
};

class MyDragWidget:public QWidget
{
private:
    QPoint * start_Pos;
    QPixmap drag_Pixmap;
public:
    MyDragWidget(QWidget * parent);
private:
    void mousePressEvent(QMouseEvent * event);
    void mouseReleaseEvent(QMouseEvent * event);
    void mouseMoveEvent(QMouseEvent * event);
};

MyDragWidget::MyDragWidget(QWidget * parent):QWidget(parent)
{
    setPalette(QPalette(QColor(0,0,0)));
    setAutoFillBackground(true);
    start_Pos = NULL;

    drag_Pixmap = QPixmap(50,50);
    QPainter painter(&drag_Pixmap);
    painter.setPen(QColor(255,0,0));
    painter.drawText(0,0,50,50,Qt::AlignCenter,"drag Pic");
    painter.end();
    resize(100,200);
}

void MyDragWidget::mousePressEvent(QMouseEvent *event)
{
    QWidget::mousePressEvent(event);
    if(event->button() == Qt::LeftButton)
    {
        if(start_Pos)
            delete start_Pos;
        start_Pos = new QPoint(event->pos());
    }
}

void MyDragWidget::mouseReleaseEvent(QMouseEvent *event)
{
    if(start_Pos)
        delete start_Pos;
    start_Pos = NULL;
}

void MyDragWidget::mouseMoveEvent(QMouseEvent *event)
{
    if(!(event->buttons() & Qt::LeftButton))
    {
        MyMessageBox mb("mouse move 0");
        mb.exec();
        return;
    }

    if(!start_Pos)
        return;
    QDrag * drag = new QDrag(this);
    drag->setPixmap(drag_Pixmap);
    QMimeData * mimeData = new QMimeData();
    mimeData->setText("name");
    drag->setMimeData(mimeData);

    Qt::DropAction dropAction = drag->exec(Qt::CopyAction,Qt::MoveAction);
}

class MyDropWidget:public QTableWidget
{
public:
    MyDropWidget(QWidget * parent);
private:
    void dragEnterEvent(QDragEnterEvent * event);
    void dropEvent(QDropEvent *event);
};

MyDropWidget::MyDropWidget(QWidget * parent):QTableWidget(parent)
{
    setColumnCount(6);
    setRowCount(9);
    setAcceptDrops(true);
    setPalette(QPalette(QColor(250,150,210)));
    setAutoFillBackground(true);
}

void MyDropWidget::dragEnterEvent(QDragEnterEvent * event)
{
    if(event->mimeData()->hasFormat("text/plain"))
        event->acceptProposedAction();

    QTableWidget::dragEnterEvent(event);
}

void MyDropWidget::dropEvent(QDropEvent * event)
{
    QString shape = event->mimeData()->text();

    MyMessageBox mm("Drop ");
    mm.exec();
    QTableWidget::dropEvent(event);
}

class Main_Widget:public QWidget
{
    MyDragWidget * courses_DragWidget;
    MyDragWidget * rooms_DragWidget;
    MyDropWidget * timeTable_Widget;
public:
    Main_Widget();
};

Main_Widget::Main_Widget()
{
    courses_DragWidget = new MyDragWidget(NULL);
    timeTable_Widget = new MyDropWidget(NULL);

    QHBoxLayout * hBoxLayout = new QHBoxLayout;
    hBoxLayout->addWidget(courses_DragWidget,1);
    hBoxLayout->addWidget(timeTable_Widget,2);

    setLayout(hBoxLayout);
}

int main(int argc,char * argv[])
{
    QApplication app(argc,argv);

    Main_Widget * main_Widget = new Main_Widget;
    main_Widget->show();
    main_Widget->resize(100,200);

    return app.exec();
}

因此，如果QTableWidget接受丢弃，则会在消息框中显示“Drop”消息。但是，不会来了=＆gt;不接受放弃。在这个问题上有人可以帮助我吗？

注意：我在Windows平台上使用Qt-4.7.2

Answer 1

您需要做两件事：

1）实施dragMoveEvent。这是在拖动进入QWidget时。实现可能如下所示：

void MyDropWidget::dragMoveEvent(QDragMoveEvent *event)
{
    event->accept();
}

当您输入拖动哑剧数据时，无需在此处再次检查，但您可以检查您希望能够插入的区域。

2）不要调用父dragEnterEvent处理程序。所以你的dragEnterEvent函数将是这样的：

void MyDropWidget::dragEnterEvent(QDragEnterEvent * event)
{
    if(event->mimeData()->hasFormat("text/plain"))
        event->acceptProposedAction();

    /* Don't need this.. QTableWidget::dragEnterEvent(event); */
}

原因是，QTableWidget支持它自己的拖放形式，所以即使你接受它，它也会将事件设置为被拒绝。

Qt - QTableWidget不接受丢弃

1 个答案: