小练习1 定时爆炸

工程代码： timer_show.rar  

http://www.cnblogs.com/hnrainll/archive/2011/05/30/2063073.html


Qt4.7.3

1. 建立工程



2. 修改 添加



3. 代码

mainwindow.h 修改

class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    enum ScreenOrientation {
        ScreenOrientationLockPortrait,
        ScreenOrientationLockLandscape,
        ScreenOrientationAuto
    };

    explicit MainWindow(QWidget *parent = 0);
    virtual ~MainWindow();

    // Note that this will only have an effect on Symbian and Fremantle.
    void setOrientation(ScreenOrientation orientation);

    void showExpanded();

private:
    Ui::MainWindow *ui;
    int num; //声明数码管初始化值对象
    QTimer *timer;

public slots:
    void mySlotStart(); //声明三个公共槽
    void mySlotCount();
    void mySlotStop();
};

mainwindow.cpp 修改

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->lcdNumber->display(9);//数码管显示9
    timer = new QTimer(this); //为timer 对象创建爱空间
    num = 9;
    //点击start按键时响应mySlotStart槽
    connect(ui->start,SIGNAL(clicked()),this,SLOT(mySlotStart()));
    //timer可以用于定时，当时间到，就会发送一个timerout()的信号,这个是循环的
    //当timerout()信号发出后响应mySlotCount()槽
    connect(timer,SIGNAL(timeout()),this,SLOT(mySlotCount()));
    //点击stop按键时响应myslotstop槽
    connect(ui->stop,SIGNAL(clicked()),this,SLOT(mySlotStop()));
}

MainWindow::~MainWindow()
{
    delete ui;
    delete timer;//add me
}


void MainWindow::mySlotStart()
{
    //定时器开始工作，初始值为1000
    timer->start(1000);
}

void MainWindow::mySlotCount()
{
    //num自减
    num--;
    if(num <= 0)
    {   //num减到0以后
        timer->stop(); //定时器 停止计时
        QLabel *label = new QLabel(this);//创建label
        ui->gridLayout->addWidget(label,0,0,2,2); //让label放在布局中，沾满整个窗口
        label->setScaledContents(true);//图片自适放大
        QMovie *movie = new QMovie("./test.gif");
        label->setMovie(movie);//播放gif图片
        movie->start();//让label显示
        label->show();

    }
    //数据显示在数码管上
    ui->lcdNumber->display(num);
}

void MainWindow::mySlotStop()
{
    //定时器暂停工作
    timer->stop();
}

显示效果