void dragEnterEvent(QDragEnterEvent *event);   //拖動進入事件
    void dropEvent(QDropEvent *event);             //放下事件

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDragEnterEvent>
#include <QUrl>
#include <QFile>
#include <QTextStream>
#include <QMimeData>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    setAcceptDrops(true); //假如這行代碼后，主窗口就可以接收放下事件了
}

MainWindow::~MainWindow()
{
    delete ui;
}

//拖動進入事件
void MainWindow::dragEnterEvent(QDragEnterEvent *event)
{
    if(event->mimeData()->hasUrls())    //數(shù)據(jù)中是否包含URL
        event->acceptProposedAction();  //接收
    else
        event->ignore();                //忽略
}

//放下事件
void MainWindow::dropEvent(QDropEvent *event)
{
    const QMimeData * mimeData = event->mimeData(); //獲取MIME數(shù)據(jù)
    if(mimeData->hasUrls())
    {
        QList<QUrl> urlList = mimeData->urls();
        QString fileName=urlList.at(0).toLocalFile();
        if(!fileName.isEmpty())
        {
            QFile file(fileName);   //建立QFile對象，以只讀方式打開文件
            if(!file.open(QIODevice::ReadOnly))
                return;
            QTextStream in(&file);      //建立文本流對象
            ui->textEdit->setText(in.readAll());
        }
    }
}

protected:
    void mousePressEvent(QMouseEvent *event);       //鼠標(biāo)按下事件
    void dragEnterEvent(QDragEnterEvent *event);    //拖動進入事件
    void dragMoveEvent(QDragMoveEvent *event);      //拖動事件
    void dropEvent(QDropEvent *event);              //放下事件

#include "mainwindow.h"
#include <QLabel>
#include "ui_mainwindow.h"
#include <QMouseEvent>
#include <QDrag>
#include <QDragEnterEvent>
#include <QDragMoveEvent>
#include <QDropEvent>
#include <QPainter>
#include <QMimeData>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    setAcceptDrops(true);                       //設(shè)置窗口部件可以接收拖入
    QLabel * label = new QLabel(this);
    QPixmap pix("..//imagedragdrop/logo.png");
    label->setPixmap(pix);
    label->resize(pix.size());
    label->move(100,100);
    label->setAttribute(Qt::WA_DeleteOnClose);  //當(dāng)窗口關(guān)閉時銷毀圖片
}

MainWindow::~MainWindow()
{
    delete ui;
}

//鼠標(biāo)按下事件
void MainWindow::mousePressEvent(QMouseEvent *event)
{
    //第1步：獲取圖片
    //將鼠標(biāo)指針?biāo)谖恢玫牟考娭妻D(zhuǎn)換為Label類型
    QLabel * child = static_cast<QLabel *>(childAt(event->pos()));
    if(!child->inherits("QLabel"))
        return;
    QPixmap pixmap = *child->pixmap();

    //第2步：自定義MIME類型
    QByteArray itemData;
    QDataStream dataStream(&itemData,QIODevice::WriteOnly);
    //將圖片信息，位置信息輸入到自己數(shù)組中
    dataStream<<pixmap<<QPoint(event->pos()-child->pos());

    //第3步：將數(shù)據(jù)放入QMimeData中
    QMimeData *mimeData = new QMimeData;
    //將字節(jié)數(shù)組放入QMimeData中，這里的MIME類型是我們自己定義的
    mimeData->setData("myimage/png",itemData);

    //第4步：將QMimeData數(shù)據(jù)放入QDrag中
    QDrag *drag = new QDrag(this);      //創(chuàng)建QDrag用來移動數(shù)據(jù)
    drag->setMimeData(mimeData);
    drag->setPixmap(pixmap);            //在移動過程中顯示圖片，若不設(shè)置則默認顯示一個小矩形
    drag->setHotSpot(event->pos()-child->pos());    //拖動時鼠標(biāo)指針的位置不變

    //第5步：給原圖添加陰影
    QPixmap tempPixmap = pixmap;
    QPainter painter;
    painter.begin(&tempPixmap);
    //在圖片的外接矩形中添加一層透明的淡黑色形成陰影效果
    painter.fillRect(pixmap.rect(),QColor(127,127,127,127));
    painter.end();
    child->setPixmap(tempPixmap);       //在移動圖片過程中，讓原圖片有一層黑色陰影

    //第6步：執(zhí)行拖放操作
    if(drag->exec(Qt::CopyAction|Qt::MoveAction,Qt::CopyAction)==Qt::MoveAction)
    {
        child->close();             //如果是移動操作，那么拖放完成后關(guān)閉原標(biāo)簽
    }
    else
    {
        child->show();              //如果是復(fù)制操作，那么拖放完成后顯示標(biāo)簽
        child->setPixmap(pixmap);   //顯示原圖片，不再使用陰影
    }

}

//拖入事件
void MainWindow::dragEnterEvent(QDragEnterEvent *event)
{
    if(event->mimeData()->hasFormat("myimage/png"))
    {
        event->setDropAction(Qt::MoveAction);
        event->accept();
    }
    else
    {
        event->ignore();
    }
}

//拖動事件
void MainWindow::dragMoveEvent(QDragMoveEvent *event)
{
    if(event->mimeData()->hasFormat("myimage/png"))
    {
        event->setDropAction(Qt::MoveAction);
        event->accept();
    }
    else
    {
        event->ignore();
    }
}

//放下事件
void MainWindow::dropEvent(QDropEvent *event)
{
    if(event->mimeData()->hasFormat("myimage/png"))
    {
        QByteArray itemData = event->mimeData()->data("myimage/png");
        QDataStream dataStream(&itemData,QIODevice::ReadOnly);
        QPixmap pixmap;
        QPoint offset;
        dataStream>>pixmap>>offset;
        QLabel * newLabel = new QLabel(this);
        newLabel->setPixmap(pixmap);
        newLabel->resize(pixmap.size());
        newLabel->move(event->pos()-offset);
        newLabel->show();
        newLabel->setAttribute(Qt::WA_DeleteOnClose);  //當(dāng)窗口關(guān)閉時銷毀圖片
        event->setDropAction(Qt::MoveAction);
        event->accept();
    }
    else
    {
        event->ignore();
    }
}

QT += printsupport

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
class QPrinter;

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

private slots:
    void doPrint();
    void doPrintPreview();
    void printPreview(QPrinter *printer);
    void createPdf();

};

#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QPrinter>
#include <QPrintDialog>
#include <QPrintPreviewDialog>
#include <QFileDialog>
#include <QFileInfo>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    QAction *action_print = new QAction(tr("打印"),this);
    QAction *action_printPreview = new QAction(tr("打印預(yù)覽"),this);
    QAction *action_pdf = new QAction(tr("生成pdf"),this);
    connect(action_print,SIGNAL(triggered()),this,SLOT(doPrint()));
    connect(action_printPreview,SIGNAL(triggered()),this,SLOT(doPrintPreview()));
    connect(action_pdf,SIGNAL(triggered()),this,SLOT(createPdf()));
    ui->mainToolBar->addAction(action_print);
    ui->mainToolBar->addAction(action_printPreview);
    ui->mainToolBar->addAction(action_pdf);

}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::doPrint()                    // 打印
{
    QPrinter printer;                         // 創(chuàng)建打印機對象
    QPrintDialog dlg(&printer, this);         // 創(chuàng)建打印對話框
    // 如果編輯器中有選中區(qū)域，則打印選中區(qū)域
    if (ui->textEdit->textCursor().hasSelection())
        dlg.addEnabledOption(QAbstractPrintDialog::PrintSelection);
    if (dlg.exec() == QDialog::Accepted) {    // 如果在對話框中按下了打印按鈕
        ui->textEdit->print(&printer);        // 則執(zhí)行打印操作
    }
}

void MainWindow::doPrintPreview()                    // 打印預(yù)覽
{
    QPrinter printer;
    QPrintPreviewDialog preview(&printer, this);     // 創(chuàng)建打印預(yù)覽對話框
    // 當(dāng)要生成預(yù)覽頁面時，發(fā)射paintRequested()信號
    connect(&preview, &QPrintPreviewDialog::paintRequested,
            this, &MainWindow::printPreview);
    preview.exec();
}

void MainWindow::printPreview(QPrinter *printer)
{
    ui->textEdit->print(printer);
}

void MainWindow::createPdf()                // 生成PDF文件
{
    QString fileName = QFileDialog::getSaveFileName(this, tr("導(dǎo)出PDF文件"),
                                                    QString(), "*.pdf");
    if (!fileName.isEmpty()) {
        if (QFileInfo(fileName).suffix().isEmpty())
            fileName.append(".pdf");        // 如果文件后綴為空，則默認使用.pdf
        QPrinter printer;
        printer.setOutputFormat(QPrinter::PdfFormat);    // 指定輸出格式為pdf
        printer.setOutputFileName(fileName);
        ui->textEdit->print(&printer);
    }
}