QTimer based Splash Screen

[wysota]

Do you have an event loop running?

[bpetty]

Header File:

#ifndef __INWAITSPLASH_H__
#define __INWAITSPLASH_H__
 
#include "ui_INWaitSplash.h"
 
#define ROWSIZE 4
#define COLUMNSIZE 4
#define TAILLENGTH 4
 
class CINWaitSplash  : public QWidget
{
    Q_OBJECT
 
public:
    CINWaitSplash(QWidget * parent = 0, Qt::WindowFlags f = Qt::SplashScreen|Qt::WindowStaysOnTopHint);
 
    void Init();
    void Start();
    void Stop();
 
protected:
    void paintEvent(QPaintEvent *);
    void InitTable();
 
private slots:
    // Table Pattern Algorithms
    void FillTable_SnakePattern();
    //void FillTable_RandomPattern();
    //void FillTable_BoxPattern();
 
private:
    Ui::SplashForm ui;
 
    QTimer* m_timerMain;
 
    int m_aiCellTable[COLUMNSIZE][ROWSIZE];
};
 
#endif

#ifndef __INWAITSPLASH_H__
#define __INWAITSPLASH_H__

#include "ui_INWaitSplash.h"

#define ROWSIZE 4
#define COLUMNSIZE 4
#define TAILLENGTH 4

class CINWaitSplash  : public QWidget
{
    Q_OBJECT

public:
    CINWaitSplash(QWidget * parent = 0, Qt::WindowFlags f = Qt::SplashScreen|Qt::WindowStaysOnTopHint);

    void Init();
    void Start();
    void Stop();

protected:
    void paintEvent(QPaintEvent *);
    void InitTable();

private slots:
    // Table Pattern Algorithms
    void FillTable_SnakePattern();
    //void FillTable_RandomPattern();
    //void FillTable_BoxPattern();

private:
    Ui::SplashForm ui;

    QTimer* m_timerMain;

    int m_aiCellTable[COLUMNSIZE][ROWSIZE];
};

#endif

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As for an event loop... I would have to say no because I am not sure what an event loop is. It is strange because if I turn the timers setInterval(100) to start(100) it will trigger... but after I run my Start() method from a function in my MainWindow it stops... and obviously stops on my Stop() method. So I know the connection is setup. I must be missing something fundamental.

[wysota]

What do you do after you call Start()? If you don't have an event loop running (either by calling QDialog::exec() or QApplication::exec() or reapeating QApplication:rocessEvents() calls) timers won't work.

[bpetty]

Interesting...

This is what I am doing.
I have a class that contains a pointer to my MainWindow and my Splash Screen Widget.
There I create a "singleton" instance of it that my class that can be used in my MainWindow's class. So inside a method of my MainWindow I am calling something like this:

void CINMainWindow::Search()
{
     INMyApp()->INWaitSplash()->Start();
     CINTimer::Sleep(1000); // Something meaningful would be done here
     INMyApp()->INWaitSplash()->Stop();
}

void CINMainWindow::Search()
{
     INMyApp()->INWaitSplash()->Start();
     CINTimer::Sleep(1000); // Something meaningful would be done here
     INMyApp()->INWaitSplash()->Stop();
}

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So I am calling Start() and Stop() to my splash screen class from any where I want.

[wysota]

It doesn't have any chance to work then. If you want to use timers, you have to call QApplication::exec() before or right after Start() and do the rest as small steps triggered by another timer with timeout set to 0, more or less like so:

void MyClass::init1(){
  //...
  QTimer::singleShot(0, this, SLOT(init2()));
}
 
void MyClass::init2(){
  //...
  QTimer::singleShot(0, this, SLOT(init3()));
}
 
// ...
 
QTimer::singleShot(0, &MyObjectOfMyClass, SLOT(init1()));
return app.exec();

void MyClass::init1(){
  //...
  QTimer::singleShot(0, this, SLOT(init2()));
}

void MyClass::init2(){
  //...
  QTimer::singleShot(0, this, SLOT(init3()));
}

// ...

QTimer::singleShot(0, &MyObjectOfMyClass, SLOT(init1()));
return app.exec();

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Timers can only timeout() when the control is in the event loop, so having a single long operation won't allow them to be triggered as well. You either have to use QApplication:rocessEvents() or use 0-timeout timers like on the example above.