在主執行緒上，可以控制子執行緒啟動，停止，清零

如果子執行緒啟動的話，每一秒鐘會向主執行緒傳送一個數字，讓主執行緒更新介面上的數字。

1. #ifndef TQT_H_
2. #define TQT_H_
3. #include <QtGui>
4. #include <QtCore>
5. class Thread : public QThread 
6. { 
7.     Q_OBJECT 
8. private: 
9.     int number; 
10. protected: 
11.     void run(); 
12. public: 
13.     Thread(QObject *parent=0); 
14.     ~Thread(); 
15. signals: 
16.     void UpdateSignal(int num); 
17.     public slots: 
18.         void ResetSlot(); 
19. }; 
20. class Widget : public QWidget 
21. { 
22.     Q_OBJECT 
23. private: 
24.     QLabel *label; 
25.     QPushButton *startButton; 
26.     QPushButton *stopButton; 
27.     QPushButton *resetButton; 
28.     Thread *myThread; 
29.     int number; 
30. public: 
31.     Widget(QWidget *parent = 0); 
32.     ~Widget(); 
33. signals: 
34.     void ResetSignal(); 
35.     public slots: 
36.         void ClearSlot(); 
37.         void StartSlot(); 
38.         void StopSlot(); 
39.         void UpdateSlot(int num); 
40. }; 
41. #endif
42. //tqt.cpp
43. #include "tqt.h"
44. #include <assert.h>
45. #include <windows.h>
46. Thread::Thread(QObject *parent) 
47. { 
48.     number = 0; 
49. } 
50. Thread::~Thread() 
51. { 
52. } 
53. void Thread::run() 
54. { 
55.     while(1) 
56.     { 
57.         emit UpdateSignal(number); 
58.         number++; 
59.         sleep(1); 
60.     } 
61. } 
62. void Thread::ResetSlot() 
63. { 
64.     number = 0; 
65.     emit UpdateSignal(number); 
66. } 
67. Widget::Widget(QWidget *parent) 
68. { 
69.     startButton = new QPushButton("start"); 
70.     stopButton = new QPushButton("stop"); 
71.     resetButton = new QPushButton("reset"); 
72.     label = new QLabel("empty"); 
73.     myThread = new Thread; 
74.     QVBoxLayout *layout = new QVBoxLayout; 
75.     layout->addWidget(label); 
76.     layout->addWidget(startButton); 
77.     layout->addWidget(stopButton); 
78.     layout->addWidget(resetButton); 
79.     setLayout(layout); 
80.     connect(stopButton, SIGNAL(clicked()),  
81.         this, SLOT(StopSlot())); 
82.     connect(startButton, SIGNAL(clicked()), 
83.         this, SLOT(StartSlot())); 
84.     connect(resetButton, SIGNAL(clicked()), 
85.         this, SLOT(ClearSlot())); 
86.     connect(myThread, SIGNAL(UpdateSignal(int)),  
87.         this, SLOT(UpdateSlot(int))); 
88.     connect(this, SIGNAL(ResetSignal()), 
89.         myThread, SLOT(ResetSlot())); 
90.     setWindowTitle("Thread Test"); 
91.     resize(200, 200); 
92.     myThread->start(); 
93. } 
94. Widget::~Widget() 
95. { 
96. } 
97. void Widget::StartSlot() 
98. { 
99.     myThread->start(); 
100. } 
101. void Widget::StopSlot() 
102. { 
103.     myThread->terminate(); 
104. } 
105. void Widget::UpdateSlot(int num) 
106. { 
107.     label->setText(QString::number(num)); 
108. } 
109. void Widget::ClearSlot() 
110. { 
111.     emit ResetSignal(); 
112. } 
113. //main.cpp
114. #include <QtGui>
115. #include "tqt.h"
116. int main(int argc,char **argv) 
117. { 
118.     QApplication app(argc, argv); 
119.     Widget *widget = new Widget; 
120.     widget->show(); 
121.     return app.exec(); 
122. } 

FROM: http://blog.csdn.net/slj_win/article/details/6856428