Qt实现贪吃蛇2:链表实现

前言

前面已经介绍了用数组实现贪吃蛇，有了前面的基础知识，所以我就开门见山了。

正文

此文是在前面的数组实现基础上加以改进的，所以说大部分还是很相似的。不过链表还是和数组有一定的区别的，所以在看此文之前，要有一些关于c链表的的知识…而且对于新手来讲还是有一定难度的。。。那么开始吧

  • 首先，我先创建一个链表类（为什么我不能Qt自带的 QLinkedList ，因为用不习惯：(

linkedlist.h

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#ifndef LINKEDLIST_H
#define LINKEDLIST_H
#include
#include
#include

class Linkedlist:QObject
{
public:
    //蛇节点
    struct SnakeNode{
        QPoint pos;
        SnakeNode* next;
        SnakeNode* prev;
    };
    Linkedlist(QObject *parent=0,QPoint headPos=QPoint()):
        QObject(parent),m_length(0){
            //初始化链表头，即蛇头
            m_head=new SnakeNode;
            m_head->pos=headPos;
            m_head->next=NULL;
            m_head->prev=NULL;
    }
    ~Linkedlist(){
            clearAllNodes();
    }
    //返回头节点
    inline SnakeNode *first()const{if(m_head){return m_head;}else return NULL;}
    //返回尾节点
    inline SnakeNode *last()const{
        if(m_head){
            SnakeNode *p1=m_head;
            SnakeNode *p2;
            do {
                p2=p1;
                p1=p1->next;
            } while (p1);
            return p2;
        }else{
            return NULL;
        }
    }
    //返回节点总数
    inline int getLength(){
         m_length=0;
         if(m_head){
             SnakeNode *p=m_head;
             do {
                 m_length+=1;
                 p=p->next;
             } while (p!=NULL);
         }
         return m_length;
    }
    //打印所以节点
    void printLinkedlist(){
        if(m_head ){
            SnakeNode *p=m_head;
            do {
                qDebug()<pos;
                p=p->next;
            } while (p);
            qDebug()<last()){
          SnakeNode *ls=this->last();
          if(ls){
              SnakeNode *p2=new SnakeNode;
              p2->prev=ls;
              p2->next=NULL;
              p2->pos=pos;

              ls->next=p2;
          }
      }
    }
    //释放所有节点
    inline void clearAllNodes(){
        if(m_head){
            SnakeNode *p=m_head;
            do {
                SnakeNode*t=p;
                m_head=p->next;
                delete t;
                t=NULL;
                p=m_head;
            } while (p);
        }
    }

private:
    int m_length;
    SnakeNode *m_head;
};
#endif // LINKEDLIST_H

这里就不多说了。。。不过要注意这里的

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//蛇节点
struct SnakeNode{
    QPoint pos;
    SnakeNode* next;
    SnakeNode* prev;
};

原本是没有 SnakeNode* prev; 的，后来在写代码时遇到点棘手的问题，所以就该了一下，变成双向链表。不过这里没有太在意这些，而且关于链表的操作也很少

widget.h

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#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include<QLinkedList>
#include<QTimer>
#include<QKeyEvent>
#include"linkedlist.h"
namespace Ui {
class Widget;
}
class QLineEdit;
class Widget : public QWidget
{
    Q_OBJECT
protected:
    void keyPressEvent(QKeyEvent *event);
    void paintEvent(QPaintEvent *event);
public:
    //蛇头移动方向
    enum SnakeDirection:int{
        Up,
        Down,
        Left,
        Right
    };
    explicit Widget(QWidget *parent = 0);
    ~Widget();
    void initializedGUI();
    void resetFoodPos();
    void checkisEatSelf();
    void checkisEatFood();
    void checkisHitWall();
    void checkFoodPosisEqualHeadPos();
    void snakeRunning();
public slots:
    void timeOut();
    void startGame();
    void stopGame();
private:
    Linkedlist *linkedlist;  //蛇链表
    int m_eatfoodCount; //吃到食物总数
    QPoint m_foodPos;//食物坐标
    int m_direction;//蛇头方向
    int m_speed;//蛇移动速度
    int m_score ;//得分
    QPoint m_tmpPosPrev;
    QTimer *m_timerControl;
    QLineEdit *leScore;
    Ui::Widget *ui;
};
#endif // WIDGET_H

widget.cpp

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#include "widget.h"
#include "ui_widget.h"
#include<QVBoxLayout>
#include<QPushButton>
#include<QLabel>
#include<QLineEdit>
#include<QPainter>
#include<QTime>
#include<QDebug>
#include<QMessageBox>
#define ROW 20 //行数
#define COLUMN 20 //列数
#define Direction 4 //方向(枚举值
void Widget::keyPressEvent(QKeyEvent *event)
{
    if(event->key()=='W'&&m_direction!=Down){
        m_direction=Up;
    }
    if(event->key()=='S'&&m_direction!=Up){
        m_direction=Down;
    }
    if(event->key()=='A'&&m_direction!=Right){
        m_direction=Left;
    }
    if(event->key()=='D'&&m_direction!=Left){
        m_direction=Right;
    }
}
void Widget::paintEvent(QPaintEvent *event)
{
    Q_UNUSED(event);
    QPen pen;
    pen.setColor(QColor(Qt::darkGray));
    QFont font;
    font.setPointSize(6);
    QPainter p(this);
    p.drawPixmap(0,0,width(),height(),QPixmap(":/img/imgs/bg.jpg"));
    p.setPen(pen);
    p.setFont(font);
    //绘制游戏布局
    for (int row = 0; row < ROW; ++row) {
        for (int column =0; column < COLUMN; ++column) {
            p.fillRect(row*20,column*20,20,20,QBrush(QColor(0,0,0,10)));
            p.drawRect(row*20,column*20,20,20);
        }
    }
    //绘制食物
    p.fillRect(m_foodPos.x()*20,m_foodPos.y()*20,20,20,
               QBrush(QPixmap(":/img/imgs/apple.png").scaled(20,20)));
    //绘制蛇
    if(linkedlist->first()){
       Linkedlist:: SnakeNode *pt=linkedlist->first();
        do{
           if(linkedlist->first()==pt){//绘制蛇头
               QPixmap pixmap;
               switch (m_direction) {
               case Up:
                   pixmap=QPixmap(":/img/imgs/up.png").scaled(20,20);
                   break;
               case Down:
                   pixmap=QPixmap(":/img/imgs/down.png").scaled(20,20);
                   break;
               case Left:
                   pixmap=QPixmap(":/img/imgs/left.png").scaled(20,20);
                   break;
               case Right:
                   pixmap=QPixmap(":/img/imgs/right.png").scaled(20,20);
                   break;
               default:
                   break;
               }
               p.fillRect(pt->pos.x()*20,
                          pt->pos.y()*20,
                          20,20,
                          QBrush(pixmap));
           }else if(linkedlist->last()==pt){ //绘制蛇尾
               QPixmap pixmap;
               pixmap=QPixmap(":/img/imgs/tail.png").scaled(20,20);
               p.fillRect(pt->pos.x()*20,
                          pt->pos.y()*20,
                          20,20,
                          QBrush(pixmap));
           }else{//绘制蛇的其他位置
               QPixmap pixmap;
               pixmap=QPixmap(":/img/imgs/body.png").scaled(20,20);
               p.fillRect(pt->pos.x()*20,
                          pt->pos.y()*20,
                          20,20,
                          QBrush(pixmap));
           }
           //指向下一个蛇身节点
            pt=pt->next;
        }while(pt!=NULL);
    }
}
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    this->setFixedSize(800,450);
    this->setWindowTitle("贪吃蛇");
    initializedGUI();
}
Widget::~Widget()
{
    delete ui;
}
///
/// \brief Widget::initializedGUI
/// 初始化
void Widget::initializedGUI()
{
    m_score=0;
    QPushButton *btnStart=new QPushButton(this);
    QPushButton *btnStop=new QPushButton(this);
    QLabel *lbScore=new QLabel(this);
    leScore=new QLineEdit(this);
    btnStart->setText(QObject::tr("开始游戏"));
    btnStop->setText(QObject::tr("暂停游戏"));
    btnStart->setFlat(true);
    btnStop->setFlat(true);
    lbScore->setText(tr("得分:"));
    leScore->setText(QString::number(m_score));
    leScore->setFocusPolicy(Qt::NoFocus);
    leScore->setEnabled(false);
    lbScore->move(500,50);
    leScore->move(560,50);
    btnStart->move(500,100);
    btnStop->move(500,150);
    connect(btnStart,SIGNAL(clicked(bool)),this,SLOT(startGame()));
    connect(btnStop,SIGNAL(clicked(bool)),this,SLOT(stopGame()));
    QTime t= QTime::currentTime();
    int s= t.secsTo(QTime(0,0,0,0));
    qsrand(s);//随机数
    m_direction=qrand()%Direction;
    switch (m_direction) {
    case Up:qDebug()<<"蛇头方向:上";
        break;
    case Down:qDebug()<<"蛇头方向:下";
        break;
    case Left:qDebug()<<"蛇头方向:左";
        break;
    case Right:qDebug()<<"蛇头方向:右";
        break;
    default:
        break;
    }
    m_foodPos.setX(qrand()%COLUMN);
    m_foodPos.setY(qrand()%ROW);
    qDebug()<<"食物坐标:"<<m_foodPos;
    m_speed=150;
    m_timerControl=new QTimer(this);
    m_timerControl->setInterval(m_speed);
    connect(m_timerControl,SIGNAL(timeout()),this,SLOT(timeOut()));
    QPoint pos;
    pos.setX(qrand()%COLUMN);
    pos.setY(qrand()%ROW);
    //在Linkedlist构造时初始化蛇头坐标
    linkedlist=new Linkedlist(this,pos);
}
///
/// \brief Widget::resetFoodPos
/// 重设食物坐标
void Widget::resetFoodPos()
{
    m_foodPos.setX(qrand()%COLUMN);
    m_foodPos.setY(qrand()%ROW);
    checkFoodPosisEqualHeadPos();
}
///
/// \brief Widget::checkisEatSelf
/// 判断是否吃到自己
void Widget::checkisEatSelf()
{
    if(linkedlist->first()){
        Linkedlist::SnakeNode *p0=linkedlist->first()->next;
        if(p0){
        do {
            //判断蛇头坐标是否等于蛇身某个节点坐标
            if(linkedlist->first()->pos==p0->pos){
                qDebug()<<"吃到自己!游戏结束";
                m_timerControl->stop();
                QMessageBox::critical(this,"game over","game over");
                this->close();
                break;
            }
            p0=p0->next;
        } while (p0);
    }
    }
}
///
/// \brief Widget::checkisEatFood
/// 检测是否吃到食物
void Widget::checkisEatFood()
{
    if(linkedlist->first()->pos.x()==m_foodPos.x()&&
            linkedlist->first()->pos.y()==m_foodPos.y()){
        qDebug()<<"吃到食物！";
        m_eatfoodCount++;
        m_score+=20;
        leScore->setText(QString::number(m_score)+" 分");
        if(m_score>=100){
            m_speed=80;
            m_timerControl->setInterval(m_speed);
        }
        //随便设置的x y 坐标
        QPoint pos=QPoint();
        linkedlist->append(pos);
        //重新设置食物坐标
        resetFoodPos();
    }
}
///
/// \brief Widget::checkisHitWall
/// 检测是否撞到墙
void Widget::checkisHitWall()
{
    if(linkedlist->first()->pos.x()<0||linkedlist->first()->pos.y()<0||
            linkedlist->first()->pos.x()>COLUMN-1||linkedlist->first()->pos.y()>ROW-1){
        m_timerControl->stop();
        qDebug()<<"撞到墙壁！游戏结束！";
        QMessageBox::critical(this,"game over","game over!");
        this->close();
    }
}
void Widget::timeOut()
{
    checkisEatFood();
    //打印出蛇身节点坐标
    linkedlist->printLinkedlist();
    //蛇身移动
    if(linkedlist->first()){
        Linkedlist::SnakeNode *p0=linkedlist->last();
        if(linkedlist->getLength()!=1&&p0){
            do {
                //把前一个节点的坐标赋值给当前节点 ，即蛇向前移动一格
                p0->pos=p0->prev->pos;
                //指向前一个节点
                p0=p0->prev;
                //因为 头结点的前一个节点为NULL
                //所以这里必须 p0!= linkedlist->first()
            } while (p0!=linkedlist->first());
        }
    }
    //蛇运动
    snakeRunning();
    checkisHitWall();
    checkisEatSelf();
    //更新绘图
    this->update();
}
///
/// \brief Widget::startGame
/// 开始游戏
void Widget::startGame()
{
    m_timerControl->start();
}
///
/// \brief Widget::stopGame
/// 结束游戏
void Widget::stopGame()
{
    m_timerControl->stop();
}
///
/// \brief Widget::snakeRunning
/// 蛇运动
void Widget::snakeRunning()
{
    int x=linkedlist->first()->pos.x();
    int y=linkedlist->first()->pos.y();
    //判断方向
    switch (m_direction) {
    case Up:
        linkedlist->first()->pos.setY(y-=1);
        break;
    case Down:
        linkedlist->first()->pos.setY(y+=1);
        break;
    case Left:
        linkedlist->first()->pos.setX(x-=1);
        break;
    case Right:
        linkedlist->first()->pos.setX(x+=1);
        break;
    default:
        break;
    }
}
///
/// \brief Widget::checkFoodPosisEqualHeadPos
/// \param head
/// \param foodPos
/// 检测食物出现坐标是否在蛇身上
void Widget::checkFoodPosisEqualHeadPos()
{
    if(linkedlist->first()){
        Linkedlist::SnakeNode *p0=linkedlist->first();
        do {
            if(p0->pos==m_foodPos){
                qDebug()<<"检测到食物处于蛇身上...";
                resetFoodPos();
            }
            p0=p0->next;
        } while (p0);
    }
}

测试
img

Bye~