【JVM】Java八股文之JVM篇

1、概述
源码放在文章末尾

可以在窗体中点击鼠标左键进行图片切换，项目提供了一些图片素材，整体风格偏向于3D类型，也可以根据需求自己放置不同的图片。

下面是demo演示：

项目部分代码如下所示：
头文件部分：

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

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

protected:
    bool eventFilter(QObject *watched, QEvent *evt);

private:
    Ui::Widget *ui;
};

#endif // WIDGET_H

逻辑实现部分：

#include "widget.h"
#include "ui_widget.h"
#include "qevent.h"
#include "qdebug.h"

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

    this->setAttribute(Qt::WA_TranslucentBackground);
    this->setWindowFlags(Qt::FramelessWindowHint | Qt::WindowSystemMenuHint | Qt::WindowMinimizeButtonHint);
    ui->widget->installEventFilter(this);
    ui->widget->setStyleSheet(QString("background-image:url(:/image/%1.png);").arg(1));
}

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

bool Widget::eventFilter(QObject *watched, QEvent *evt)
{
    static int index = 1;
    static QPoint mousePoint;
    static bool mousePressed = false;

    QMouseEvent *event = static_cast<QMouseEvent *>(evt);
    if (event->type() == QEvent::MouseButtonPress) {
        if (event->button() == Qt::LeftButton) {
            mousePressed = true;
            mousePoint = event->globalPos() - this->pos();

            if (index == 5) {
                index = 1;
            } else {
                index++;
            }

            ui->widget->setStyleSheet(QString("background-image:url(:/image/%1.png);").arg(index));

            return true;
        } else {
            exit(0);
        }
    } else if (event->type() == QEvent::MouseButtonRelease) {
        mousePressed = false;
        return true;
    } else if (event->type() == QEvent::MouseMove) {
        if (mousePressed && (event->buttons() && Qt::LeftButton)) {
            this->move(event->globalPos() - mousePoint);
            return true;
        }
    }

    return QWidget::eventFilter(watched, event);
}

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