效果
由于录制程序的原因，引起gif效果不清晰，可忽略。
源码
QProgressIndicator.h
1 #ifndef QPROGRESSINDICATOR_H
2 #define QPROGRESSINDICATOR_H
3
4 #include <QWidget>
5 #include <QColor>
6
7 /*!
8 \class QProgressIndicator
9 \brief The QProgressIndicator class lets an application display a progress indicator to show that a lengthy task is under way.
10
11 Progress indicators are indeterminate and do nothing more than spin to show that the application is busy.
12 \sa QProgressBar
13 */
14 class QProgressIndicator : public QWidget
15 {
16 Q_OBJECT
17 Q_PROPERTY(int delay READ animationDelay WRITE setAnimationDelay)
18 Q_PROPERTY(bool displayedWhenStopped READ isDisplayedWhenStopped WRITE setDisplayedWhenStopped)
19 Q_PROPERTY(QColor color READ color WRITE setColor)
20 public:
21 QProgressIndicator(QWidget* parent = 0);
22
23 /*! Returns the delay between animation steps.
24 \return The number of milliseconds between animation steps. By default, the animation delay is set to 40 milliseconds.
25 \sa setAnimationDelay
26 */
27 int animationDelay() const { return m_delay; }
28
29 /*! Returns a Boolean value indicating whether the component is currently animated.
30 \return Animation state.
31 \sa startAnimation stopAnimation
32 */
33 bool isAnimated () const;
34
35 /*! Returns a Boolean value indicating whether the receiver shows itself even when it is not animating.
36 \return Return true if the progress indicator shows itself even when it is not animating. By default, it returns false.
37 \sa setDisplayedWhenStopped
38 */
39 bool isDisplayedWhenStopped() const;
40
41 /*! Returns the color of the component.
42 \sa setColor
43 */
44 const QColor & color() const { return m_color; }
45
46 virtual QSize sizeHint() const;
47 int heightForWidth(int w) const;
48 public slots:
49 /*! Starts the spin animation.
50 \sa stopAnimation isAnimated
51 */
52 void startAnimation();
53
54 /*! Stops the spin animation.
55 \sa startAnimation isAnimated
56 */
57 void stopAnimation();
58
59 /*! Sets the delay between animation steps.
60 Setting the \a delay to a value larger than 40 slows the animation, while setting the \a delay to a smaller value speeds it up.
61 \param delay The delay, in milliseconds.
62 \sa animationDelay
63 */
64 void setAnimationDelay(int delay);
65
66 /*! Sets whether the component hides itself when it is not animating.
67 \param state The animation state. Set false to hide the progress indicator when it is not animating; otherwise true.
68 \sa isDisplayedWhenStopped
69 */
70 void setDisplayedWhenStopped(bool state);
71
72 /*! Sets the color of the components to the given color.
73 \sa color
74 */
75 void setColor(const QColor & color);
76 protected:
77 virtual void timerEvent(QTimerEvent * event);
78 virtual void paintEvent(QPaintEvent * event);
79 private:
80 int m_angle;
81 int m_timerId;
82 int m_delay;
83 bool m_displayedWhenStopped;
84 QColor m_color;
85 };
86
87 #endif // QPROGRESSINDICATOR_H
QProgressIndicator.cpp
1 #include "QProgressIndicator.h"
2
3 #include <QPainter>
4
5 QProgressIndicator::QProgressIndicator(QWidget* parent)
6 : QWidget(parent),
7 m_angle(0),
8 m_timerId(-1),
9 m_delay(40),
10 m_displayedWhenStopped(false),
11 m_color(Qt::black)
12 {
13 setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
14 setFocusPolicy(Qt::NoFocus);
15 }
16
17 bool QProgressIndicator::isAnimated () const
18 {
19 return (m_timerId != -1);
20 }
21
22 void QProgressIndicator::setDisplayedWhenStopped(bool state)
23 {
24 m_displayedWhenStopped = state;
25
26 update();
27 }
28
29 bool QProgressIndicator::isDisplayedWhenStopped() const
30 {
31 return m_displayedWhenStopped;
32 }
33
34 void QProgressIndicator::startAnimation()
35 {
36 m_angle = 0;
37
38 if (m_timerId == -1)
39 m_timerId = startTimer(m_delay);
40 }
41
42 void QProgressIndicator::stopAnimation()
43 {
44 if (m_timerId != -1)
45 killTimer(m_timerId);
46
47 m_timerId = -1;
48
49 update();
50 }
51
52 void QProgressIndicator::setAnimationDelay(int delay)
53 {
54 if (m_timerId != -1)
55 killTimer(m_timerId);
56
57 m_delay = delay;
58
59 if (m_timerId != -1)
60 m_timerId = startTimer(m_delay);
61 }
62
63 void QProgressIndicator::setColor(const QColor & color)
64 {
65 m_color = color;
66
67 update();
68 }
69
70 QSize QProgressIndicator::sizeHint() const
71 {
72 return QSize(20,20);
73 }
74
75 int QProgressIndicator::heightForWidth(int w) const
76 {
77 return w;
78 }
79
80 void QProgressIndicator::timerEvent(QTimerEvent * /*event*/)
81 {
82 m_angle = (m_angle+30)%360;
83
84 update();
85 }
86
87 void QProgressIndicator::paintEvent(QPaintEvent * /*event*/)
88 {
89 if (!m_displayedWhenStopped && !isAnimated())
90 return;
91
92 int width = qMin(this->width(), this->height());
93
94 QPainter p(this);
95 p.setRenderHint(QPainter::Antialiasing);
96
97 int outerRadius = (width-1)*0.5;
98 int innerRadius = (width-1)*0.5*0.38;
99
100 int capsuleHeight = outerRadius - innerRadius;
101 int capsuleWidth = (width > 32 ) ? capsuleHeight *.23 : capsuleHeight *.35;
102 int capsuleRadius = capsuleWidth/2;
103
104 for (int i=0; i<12; i++)
105 {
106 QColor color = m_color;
107 color.setAlphaF(1.0f - (i/12.0f));
108 p.setPen(Qt::NoPen);
109 p.setBrush(color);
110 p.save();
111 p.translate(rect().center());
112 p.rotate(m_angle - i*30.0f);
113 p.drawRoundedRect(-capsuleWidth*0.5, -(innerRadius+capsuleHeight), capsuleWidth, capsuleHeight, capsuleRadius, capsuleRadius);
114 p.restore();
115 }
116 }
使用
1 QProgressIndicator *pIndicator = new QProgressIndicator(this);
2 pIndicator->setColor(Qt::white);
3 pIndicator->startAnimation();
源码没什么难度，有兴趣的可以根据需要自行修改。
