QT QGraphicsView QGraphicsScene用法

graphics view 框架结构主要包含三个类，场景类（qgraphicsscene），视图类(qgraphicsview)和图元类(qgraphicsitem)

 

 

 

 

 

#include "dialog.h"

#include 

#include "ui_dialog.h"

// 游戏的初始速度

static const qreal INITSPEED = 500;

Dialog::Dialog(QWidget *parent) :

    QDialog(parent),

    ui(new Ui::Dialog)

{

    ui->setupUi(this);

    //设置场景

    QGraphicsScene *scene = new QGraphicsScene();

    scene->setSceneRect(0,0, 750, 580);

    ui->graphicsView->setScene(scene);

    //scene->setBackgroundBrush(QPixmap(":/images/background.png"));

    topLine = scene->addLine(100,20, 400, 20);

    bottomLine = scene->addLine(100,520, 400, 520);

    leftLine = scene->addLine(100, 20, 100, 520);

    rightLine = scene->addLine(400,20,400,520);

    // 当前方块组和提示方块组

    boxGroup = new BoxGroup;

    connect(boxGroup, SIGNAL(needNewBox()), this, SLOT(clearFullRows()));

    connect(boxGroup, SIGNAL(gameFinished()), this, SLOT(gameOver()));

    scene->addItem(boxGroup);

    nextBoxGroup = new BoxGroup;

    scene->addItem(nextBoxGroup);

    startGame();

}

// 开始游戏

void Dialog::startGame()

{

    initGame();

}

// 初始化游戏

void Dialog::initGame()

{

    boxGroup->createBox(QPointF(300, 70));

    boxGroup->setFocus();

    boxGroup->startTimer(INITSPEED);

    gameSpeed = INITSPEED;

    nextBoxGroup->createBox(QPointF(640, 70));

}

// 清空满行

void Dialog::clearFullRows()

{

    // 获取比一行方格较大的矩形中包含的所有小方块

    for (int y = 429; y > 50; y -= 20) {

        QList<QGraphicsItem *> list = ui->graphicsView->scene()->items(199, y, 202, 22, Qt::ContainsItemShape, Qt::AscendingOrder);

        // 如果该行已满

        if (list.count() == 10) {

            foreach (QGraphicsItem *item, list) {

                mybox *box = (mybox*) item;

                box->deleteLater();

            }

            // 保存满行的位置

            rows << y;

        }

    }

    // 如果有满行，下移满行上面的各行再出现新的方块组

    // 如果没有满行，则直接出现新的方块组

    if(rows.count() > 0) {

        moveBox();

    } else {

        boxGroup->createBox(QPointF(300, 70), nextBoxGroup->getCurrentShape());

        // 清空并销毁提示方块组中的所有小方块

        nextBoxGroup->clearBoxGroup(true);

        nextBoxGroup->createBox(QPointF(500, 70));

    }

}

// 下移满行上面的所有小方块

void Dialog::moveBox()

{

    // 从位置最靠上的满行开始

    for (int i = rows.count(); i > 0;  --i) {

        int row = rows.at(i - 1);

        foreach (QGraphicsItem *item,ui->graphicsView->scene()->items(199, 49, 202, row - 47, Qt::ContainsItemShape, Qt::AscendingOrder)) {

            item->moveBy(0, 20);

        }

    }

    // 更新分数

    updateScore(rows.count());

    // 将满行列表清空为0

    rows.clear();

    // 等所有行下移以后再出现新的方块组

    boxGroup->createBox(QPointF(300, 70), nextBoxGroup->getCurrentShape());

    nextBoxGroup->clearBoxGroup(true);

    nextBoxGroup->createBox(QPointF(500, 70));

}

void Dialog::updateScore(const int fullRowNum)

{

    // 更新分数

}

void Dialog::gameOver()

{

    // 游戏结束

}

Dialog::~Dialog()

{

    delete ui;

}