Hi guys,

I created this Qt Application project under VS2005, and tried to display the GPS data onto GUI---real simple. I can read the data from the serial port fine (using QExtSerialPort class) but I cant display it on the GUI for some reason. The GUI would just be non-responsive and I have to kill it. If you guys could help me out here, that'd be great. I tried to compare this to other existing tutorials I have been working on, but couldnt find anything. In particular, I simply call label->setText() to display the string :

Qt Code: 
  1. #ifndef QTAPP_H
  2. #define QTAPP_H
  3.  
  4. #include <QtGui/QMainWindow>
  5. #include "ui_qtapp.h"
  6. #include <QLabel>
  7. #include <QIODevice>
  8. #include <QString>
  9. #include <QApplication>
  10. #include <QStringList>
  11. #include <QDebug>
  12. #include <QVariant>
  13. #include <QWidget>
  14. #include "qextserialport.h"
  15.  
  16. class QtApp : public QMainWindow
  17. {
  18. 	Q_OBJECT
  19.  
  20. public:
  21. 	QtApp(QWidget *parent = 0, Qt::WFlags flags = 0);
  22. 	~QtApp();
  23. 	void Run();
  24.  
  25. private:
  26. 	Ui::QtAppClass ui;
  27. 	QString*			str;
  28. 	QStringList*		list;
  29. 	QextSerialPort*		port;
  30. };
  31.  
  32. #endif // QTAPP_H
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Qt Code: 
  1. #include "qtapp.h"
  2.  
  3. QtApp::QtApp(QWidget *parent, Qt::WFlags flags)
  4. 	: QMainWindow(parent, flags)
  5. {
  6. 	ui.setupUi(this);
  7.  
  8. 	str  = new QString;
  9. 	list = new QStringList;
  10. 	port = new QextSerialPort( "COM1" );
  11. 	port->setBaudRate(BAUD115200);   
  12. 	port->setFlowControl(FLOW_OFF);
  13. 	port->setParity(PAR_NONE);    
  14. 	port->setDataBits(DATA_8);   
  15. 	port->setStopBits(STOP_1);   
  16.  
  17. 	// Open port
  18. 	port->open( QIODevice::ReadOnly );
  19. }
  20.  
  21. QtApp::~QtApp()
  22. {
  23.  
  24. }
  25.  
  26. void QtApp::Run()
  27. {
  28. 	char data[100];
  29.  
  30. 	QLabel* label = new QLabel;
  31. 	while(1)
  32. 	{
  33. 		if( !port->bytesAvailable() )	continue;
  34.  
  35. 		int				charIdx = 0;
  36. 		int				bytesRead;
  37.  
  38. 		//
  39. 		// Find sync word
  40. 		do
  41. 		{
  42. 			data[charIdx] = 'A';
  43. 			port->read( data,
  44. 						1 );
  45. 		} while( data[charIdx] != '$' );
  46. 		charIdx++;
  47.  
  48. 		//
  49. 		// Read the rest of the data
  50. 		do
  51. 		{
  52. 			charIdx += port->read( &data[charIdx],
  53. 								   1 );
  54. 		} while( data[charIdx-1] != '*' );
  55.  
  56.  
  57. 		// Read check sum
  58. 		charIdx += port->read( &data[charIdx],
  59. 							   2 );
  60. 		data[charIdx] = '\0';
  61.  
  62.  
  63. 		// Copy buffer to QString
  64. 		*str = data;
  65.  
  66. 		//
  67. 		// Diplay this on GUI
  68. 		label->setText( *str );
  69. 	}
  70. }
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