<clock.h >
#ifndef CLOCK_H
#define CLOCK_H
#include <QWidget>
class Clock : public QWidget
{
//对于具有signal，slot机制的类需要声明
Q_OBJECT
public:
Clock(QWidget *parent = 0);
protected:
//重绘用的事件处理函式
void paintEvent(QPaintEvent *event);
};
#endif // CLOCK_H
<cpp文件>
1 #include "clock.h"
2
3
4 #include <QtGui>
5
6 #include "clock.h"
7
8 Clock::Clock(QWidget *parent): QWidget(parent)
9 {
10 //声明一个定时器
11 QTimer *timer = new QTimer(this);
12 //连接信号与槽
13 connect(timer, SIGNAL(timeout()), this, SLOT(update()));
14 timer->start(1000);
15 //设置窗体名称与大小
16 setWindowTitle(tr("Clock"));
17 resize(200, 200);
18
19 }
20
21
22 void Clock::paintEvent(QPaintEvent *)
23
24 {
25 //下面三个数组用来定义表针的三个顶点，以便后面的填充
26 static const QPoint hourHand[3] = {
27 QPoint(3, 8),
28 QPoint(-3, 8),
29 QPoint(0, -40)
30 };
31 static const QPoint minuteHand[3] = {
32 QPoint(3, 8),
33 QPoint(-3, 8),
34 QPoint(0, -70)
35 };
36 static const QPoint secondHand[3] = {
37 QPoint(3, 8),
38 QPoint(-3, 8),
39 QPoint(0, -90)
40 };
41
42 //填充表针的颜色
43 QColor hourColor(127, 0, 127);
44 QColor minuteColor(0, 127, 127, 191);
45 QColor secondColor(127, 127,0,120);
46 //绘制的范围
47 int side = qMin(width(), height());
48 //获取当前的时间
49 QTime time = QTime::currentTime();
50 //声明用来绘图用的“画家”
51 QPainter painter(this);
52
53 painter.setRenderHint(QPainter::Antialiasing);
54 //重新定位坐标起始点点
55 painter.translate(width() / 2, height() / 2);
56 //设定花布的边界
57 painter.scale(side / 200.0, side / 200.0);
58 //填充时针，不需要边线所以NoPen
59 painter.setPen(Qt::NoPen);
60 //画刷颜色设定
61 painter.setBrush(hourColor);
62 //保存“画家”的状态
63 painter.save();
64 //将“画家”（的”视角“）根据时间参数转移
65 painter.rotate(30.0 * ((time.hour() + time.minute() / 60.0)));
66 //填充时针的区域
67 painter.drawConvexPolygon(hourHand, 3);
68 //恢复填充前“画家”的状态
69 painter.restore();
70
71 //下面画表示小时的刻度，此时要用到画笔（因为要划线）
72 painter.setPen(hourColor);
73 //十二个刻度，循环下就好了
74 for (int i = 0; i < 12; ++i) {
75 //没次都是这样，先画跳线，再转个角
76 painter.drawLine(88, 0, 96, 0);
77 painter.rotate(30.0);
78 }
79
80 //后面的跟前面的类似，分别绘制了分针和秒针，及相应的刻度，我就不废话了
81
82 painter.setPen(Qt::NoPen);
83
84 painter.setBrush(minuteColor);
85
86
87 painter.save();
88 painter.rotate(6.0 * (time.minute() + time.second() / 60.0));
89 painter.drawConvexPolygon(minuteHand, 3);
90 painter.restore();
91
92 painter.setPen(minuteColor);
93
94 for (int j = 0; j < 60; ++j) {
95 if ((j % 5) != 0)
96 painter.drawLine(92, 0, 96, 0);
97 painter.rotate(6.0);
98 }
99
100
101 painter.setPen(Qt::NoPen);
102
103 painter.setBrush(secondColor);
104
105 painter.save();
106 painter.rotate(6.0*time.second());
107 painter.drawConvexPolygon(secondHand,3);
108 painter.restore();
109
110 }
<main文件>
#include <QApplication>
#include "clock.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
//声明下，再show出来就可以了
Clock clock;
clock.show();
return app.exec();
}
<pro文件>
HEADERS = clock.h
SOURCES = clock.cpp \
main.cpp
