QDrag dropEvent dragEnterEvent 实现自定义控件拖拽 基本控件（一）

一、效果图

二、代码构造思路
捕获鼠标点击事件，构建QDrag对象设置部件pixmap.重写dropEvent dragEnterEvent 实现自定义控件拖拽
三、代码片段

#include "dragdropwidget.h"
#include "ui_dragdropwidget.h"

dragdropwidget::dragdropwidget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::dragdropwidget)
{
    m_srcIndex = -1;

    setAcceptDrops(true);

    ui->setupUi(this);
    for(int i=0;i<4;i++){
        QLabel *btn = new QLabel(this);
        btn->setStyleSheet("background-color:#A9A9A9;font-family: Microsoft YaHei;font:bold 12px;color: #666666;text-align:right;");
        btn->setText("LeftBtn"+QString::number(i));
        ui->verticalLayout->addWidget(btn);
    }
    ui->verticalLayout->addStretch();

    for(int i=0;i<4;i++){
        QLabel *btn = new QLabel(this);
        btn->setStyleSheet("background-color:#A9A9A9;font-family: Microsoft YaHei;font:bold 12px;color: #666666;text-align:center;");
        btn->setText("RightBtn"+QString::number(i));
        ui->verticalLayout_2->addWidget(btn);
    }
    ui->verticalLayout_2->addStretch();

    m_bleft = false;
    m_bright = false;;
}

dragdropwidget::~dragdropwidget()
{
    delete ui;
}
int dragdropwidget::itemPressed(const QPoint &pos)
{
    for (int index = 0; index < ui->verticalLayout->count()-1; index++)
    {
        QLayoutItem *item = ui->verticalLayout->itemAt(index);
        if (item->widget()->isVisible())
        {
            QRect rect = item->widget()->geometry();
            if(rect.contains(pos)){
                m_bleft = true;
                return index;
            }
        }
    }
    for (int index = 0; index < ui->verticalLayout_2->count()-1; index++)
    {
        QLayoutItem *item = ui->verticalLayout_2->itemAt(index);
        if (item->widget()->isVisible())
        {
            QRect rect = item->widget()->geometry();
            if(rect.contains(pos)){
                m_bright = true;
                return index;
            }
        }
    }
    return -1;
}

void dragdropwidget::dropEvent(QDropEvent *event)
{
    qDebug()<<"dropEvent";
    if(m_bleft)
    {
        ui->verticalLayout_2->insertWidget(ui->verticalLayout_2->count()-1,m_pwidget);m_pwidget->show();
    }
    else if(m_bright)
    {
        ui->verticalLayout->insertWidget(ui->verticalLayout->count()-1,m_pwidget);m_pwidget->show();
    }

    event->setDropAction(Qt::MoveAction);
    event->accept();
}

void dragdropwidget::dragEnterEvent(QDragEnterEvent *event)
{
    event->setDropAction(Qt::MoveAction);
    event->accept();
}

void dragdropwidget::mousePressEvent(QMouseEvent *event)
{
    m_bleft = false;
    m_bright = false;
    m_srcIndex = itemPressed(event->pos());
    qDebug()<<"m_srcIndex"<<m_srcIndex;
    if(m_srcIndex == -1)
        return;
    QWidget *child;
    if(m_bleft)
    {
        child = ui->verticalLayout->takeAt(m_srcIndex)->widget();
        ui->verticalLayout->removeWidget(child);
    }
    else if(m_bright)
    {
        child = ui->verticalLayout_2->takeAt(m_srcIndex)->widget();
        ui->verticalLayout_2->removeWidget(child);
    }
    child->hide();
    m_pwidget = child;
    ui->verticalLayout->removeWidget(child);

    QDrag *drag = new QDrag(this);
    QPixmap image = child->grab(child->rect());
    QMimeData *mimeData = new QMimeData;
    mimeData->setData("data", "");

    drag->setPixmap(image);
    drag->setMimeData(mimeData);
    drag->setHotSpot(event->pos() - child->pos());
    drag->exec(Qt::MoveAction);
}

void dragdropwidget::mouseMoveEvent(QMouseEvent *event)
{
    qDebug()<<"event->pos"<<event->pos();
}

四、结语
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