图片拖动并交换图片-使用观察者模式

使用观察者模式来做。主窗口是观察者，图片控件是被观察者，

图片被拖动的时候，图片控件要通知观察者，移动之后的位置坐标+图片控件本身的索引号

MySubject.h（被观察者-抽象类）

#ifndef MYSUBJECT_H
#define MYSUBJECT_H

#include "observer.h"


class MySubject
{
public:
    MySubject();

    virtual void registerOb(Observer*) = 0;
};

#endif // MYSUBJECT_H

MySubject.cpp

#include "MySubject.h"

MySubject::MySubject()

{

}

Hero.h（被观察者-实例类）

#ifndef HERO_H
#define HERO_H

#include "MySubject.h"
#include <QToolButton>
#include <QMouseEvent>

class Hero : public QToolButton,MySubject
{
    Q_OBJECT
public:
    explicit Hero(QWidget *parent = nullptr);

    ~Hero();

public:
    void setImage(const QString&,int);
    void registerOb(Observer*);


protected:
    void mousePressEvent(QMouseEvent *event);
    void mouseMoveEvent(QMouseEvent *event);
    void mouseReleaseEvent(QMouseEvent *event);


private:
    QPoint m_pressPoint;//鼠标按下的位置
    QPoint m_pressPointUI;//鼠标按下时控价的位置

private:
    Observer* m_Ob;

public:
    int mId;
};

#endif // HERO_H

Hero.cpp

#include "Hero.h"
#include "mainwindow.h"
#include <QDebug>

Hero::Hero(QWidget *parent) : QToolButton(parent)
{
    m_pressPointUI = this->pos();
}

Hero::~Hero()
{

}

void Hero::setImage(const QString& s_image, int id)
{
//    QImage image(s_image);
//    int w = image.width();
//    int h = image.height();
    int w = 80;
    int h = 80;
    this->setFixedSize(w,h);
    this->setIconSize(QSize(w,h));
    this->setIcon(QIcon(s_image));

    mId = id;
}

void Hero::registerOb(Observer* p)
{
    m_Ob = p;
}


void Hero::mousePressEvent(QMouseEvent *event)
{
    m_pressPoint = event->pos();

    m_pressPointUI = this->pos();


    this->raise();

}

void Hero::mouseMoveEvent(QMouseEvent *event)
{
    QPoint dis = event->pos() - m_pressPoint;
    this->move(this->pos() + dis);

}

void Hero::mouseReleaseEvent(QMouseEvent *event)
{

    m_Ob->update(mId, this->pos() + event->pos());

    this->move(m_pressPointUI);

}

observer.h（观察者-抽象类）

#ifndef OBSERVER_H
#define OBSERVER_H

#include <QPoint>

class Observer
{
public:
    Observer();
    virtual void update(int id, QPoint pos)=0;
};

#endif // OBSERVER_H

observer.cpp

#include "observer.h"

Observer::Observer()

{

}

mainwindow.h（观察者-实例类）

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include "Hero.h"
#include "observer.h"
#include <QMainWindow>
#include <QVector>


QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow, Observer
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

    void init();

    virtual void update(int index, QPoint pos);

private:
    QVector<Hero*> mHero;

private:
    Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>

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

    init();
}

MainWindow::~MainWindow()
{
//    for (auto p : mHero)
//    {
//        delete  p;
//        p = nullptr;
//    }

//    mHero.clear();

    delete ui;
}

void MainWindow::init()
{

    Hero* p1 = new Hero(this);
    p1->setImage("D:/ss/s3/untitled/image/h1.jpeg",0);
    p1->move(0,0);
    p1->registerOb(this);

    Hero* p2 = new Hero(this);
    p2->setImage("D:/ss/s3/untitled/image/h2.jpeg",1);
    p2->move(410,0);
    p2->registerOb(this);

    Hero* p3 = new Hero(this);
    p3->setImage("D:/ss/s3/untitled/image/h3.jpeg",2);
    p3->move(0,410);
    p3->registerOb(this);

    Hero* p4 = new Hero(this);
    p4->setImage("D:/ss/s3/untitled/image/h4.jpeg",3);
    p4->move(410,410);
    p4->registerOb(this);

    mHero.append(p1);
    mHero.append(p2);
    mHero.append(p3);
    mHero.append(p4);
}

void MainWindow::update(int index, QPoint pos)
{

    for (int i =0;i<mHero.size();i++)
    {
        if (mHero[i]->geometry().contains(pos) && mHero[i]->mId != index)
        {
            //交换图片
            QIcon icon = mHero[index]->icon();
            mHero[index]->setIcon(mHero[i]->icon());
            mHero[i]->setIcon(icon);
        }

    }
}