创建单独的计时器以创建速度和球

Question

我正在努力下降的球应用程序， 关于应用程序：球不断定期下降，并且有一个篮子抓住球。如果被抓住，那么我们就会赢得一点点，然后丧生。

对于此应用程序，我使用QT和CPP。 我创建了一个级别的精灵，并具有有关球（x和y）和速度（DX和DY）的初始位置的规格。 我正在使用一个计时器来实现球的速度，但是我需要定期进行另一个计时器来创建球。谁能帮助我如何定期实施球？

sprite.h
--------
#ifndef SPRITE_H
#define SPRITE_H

#include <QTimer>
#include <QPainter>
#include <QWidget>

/**
 * Header class for Sprite
 */
class Sprite : public QTimer
{
public:
    Sprite(QWidget *parent);
    //draw() to draw a sprite
    void draw(QPainter &painter);
protected:
    //This timerEvent will be called after certain time prescribed.
    virtual void timerEvent(QTimerEvent *e) override;

    int x;//position of sprite in x-direction.
    int y;//position of sprite in y-direction.
    int dx;//difference in x-direction position.
    int dy;//difference in y-direction position.
    int x1;//position of the basket in x-direction
    int y1;//position of the basket in y-direction.
    QWidget *parent;//parent class for all widgets.

};
#endif // SPRITE_H


sprite.cpp
-----------
#include "sprite.h"
#include <QDebug>

Sprite::Sprite(QWidget *parent):parent(parent)
{
    QRect rct = parent->rect();
    x = rand() % rct.width();//randomly initialize the x-position for the sprite.
    y=rct.height()*0.05;//start position for the sprite is about 5% after the top of the menu bar.

    dx = rand() % 10;//the speed is randomly set in x-direction.

//    dy = rand() % 10;//the speed is randomly set in y-direction.
    dy = 4;

    x1=rct.width()/2;
    y1 = rct.height()-80;

    start(10);

}

void Sprite::draw(QPainter &painter)
{
    qDebug() <<"Sprite::draw() called";
    painter.drawEllipse(x, y, 15, 15);//ball
    painter.drawRect( x1, y1, 80, 30);//basket
}


void Sprite::timerEvent(QTimerEvent *)
{
    qDebug("timerEvent called");
    QRect rct = parent->rect();
    if ( x > rct.width() || x < 0)
        dx *= -1;
    if ( y > rct.height() || y < 0){}

    x += dx;
    y += dy;
    parent->update();
}

mainwindow.cpp
-----------------
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>
#include <QKeyEvent>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    qDebug() <<"mainWindow constructor";

      QTimer timer;
    QObject::connect(&timer, &QTimer::timeout, this,&MainWindow::onTimer);
    timer.start(1000);
}

MainWindow::~MainWindow()
{
    qDebug() <<"mainWindow destructor";
    delete ui;
}
void MainWindow::onTimer()
{
    std::cout << "Tick!-----------------------------------------------------------------------------" << std::endl;

}
  


void MainWindow::paintEvent(QPaintEvent *)
{
    qDebug() <<"painEvent() called";
    QPainter painter(this);

    painter.fillRect(rect(), QBrush(QColor(Qt::white)));

    painter.setPen(Qt::black);
    painter.setBrush(QBrush(QColor(Qt::darkBlue)));
    emit draw(painter);
}
    
MainWindow.h
-----------
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "sprite.h"
#include <balls.h>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow

{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();
signals:
    void draw(QPainter &painter);
    void move(int nDirection);

protected:
    //This event handler captures all the paint events request to repaint all or part of the widget.
    void paintEvent(QPaintEvent* event)override;
    
public slots:
    void onTimer();

private slots:
    void on_actionStart_triggered();

    void on_actionStop_triggered();

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

我如何定期创建球，任何sudo代码都会有所帮助。

也欢迎任何更好的实施方法。

Answer 1

调用 qobject :: startTimer 将同时运行两个计时器：

int timerId1 = startTimer(2000);
int timerId2 = startTimer(10);

void MyObject::timerEvent(QTimerEvent *event)
{
    if (event->timerId() == timerId1)
        ; // 2000ms timer is fired
     else if (event->timerId() == timerId2)
        ; // 10ms timer is fired
}

qt文档此用例的示例。

另一种选择是使用两个 qtimer对象，对象，对象并将一个插槽连接到每个qtimer对象的超时信号。