Out of memory when rotating device

[Maysoon88]

Hi all,

In my qt mobile application when I rotate the device either by code or on real it is giving me this error:

[Qt message] QImage: out of memory returning null image

knowing that I don't have images in my widget it is just simple controls!!!! help please!

[negus]

Post some part of code

[Maysoon88]

Post some part of code

hi actually its not a small code and I can't figure out which part makes that problem but it occurres just when I rotate the device you know !!! the screen goes white and it gives me that error!!!

[symbianyucca]

you are propably leaking memory, thus check the functions called during the rotation and see what you are doing in them. i.e. any sensor code, as well as any function used for resizing.

[danhicksbyron]

Yep, sounds like a memory leak.

This bit of code will display heap usage:

#ifdef Q_OS_SYMBIAN
#include <e32std.h>  // Link against euser.lib
#endif
.
.
.
void HeapLeak::updateHeapStats() {
#ifdef Q_OS_SYMBIAN
	TInt mem, size, limit;
	User::Heap().AllocSize(mem);
	size = User::Heap().Size();
	limit = User::Heap().MaxLength();
	ui.memLabel ->setText(QString::number(mem));
	ui.memLabel ->update();
	ui.sizeLabel ->setText(QString::number(size));
	ui.sizeLabel ->update();
	ui.limitLabel ->setText(QString::number(limit));
	ui.limitLabel ->update();
#endif
}

(Create labels memLabel, sizeLabel, and limitLabel on your screen, or alternatively display the values in a QMessageBox.)

[Maysoon88]

you are propably leaking memory, thus check the functions called during the rotation and see what you are doing in them. i.e. any sensor code, as well as any function used for resizing.

Hi, actually I don't call any functions I just rotate the device many times while am on the same widget how can that make a leak ??? my widget contains 4 buttons and a tree widget thats all !!!!

[Sorcery-ltd]

Are your widgets standard Qt widgets only, or have you done some customization? When you rotate the device all of their sizes will be changed - I guess something in that call path is leaking memory. I'd strongly suspect something in the tree widget as a first guess.

[Maysoon88]

Are your widgets standard Qt widgets only, or have you done some customization? When you rotate the device all of their sizes will be changed - I guess something in that call path is leaking memory. I'd strongly suspect something in the tree widget as a first guess.

no that happenes even with other widgets that do not contain tree widget....!!!

[Sorcery-ltd]

Well look for a component that's common to all the cases where it does happen.

[Maysoon88]

Ok, more tests, I have included the code below and put it after the call that crashes the application, here are the numbers:
Mem = 6804436
Size = 8351624
Limit = 8388608

am I hitting the limit? I started to believe that there is a leak some where, how could I detect the leaks using Qt Creator?
I tried increasing the TARGET.EPOCHEAPSIZE = 0x010000 0x8000000 but with no luck.
Here is a snippet of the class that triggers the crash,I put it all, as I have no leak detection tools to determine the code responsible for the problem.

#include "headlinewidget.h"
#include "ui_headlinewidget.h"
#include <QLCDNumber>
#include "mylabel.h"


#ifdef Q_OS_SYMBIAN
#include <AknAppUi.h>
#include <e32std.h>  // Link against euser.lib
#endif

void HeadlineWidget::updateHeapStats() {
#ifdef Q_OS_SYMBIAN
        TInt mem, size, limit;
        User::Heap().AllocSize(mem);
        size = User::Heap().Size();
        limit = User::Heap().MaxLength();

        QMessageBox msgBox1;
        QString tmp = "Mem = " + QString::number(mem) + "  Size = " + QString::number(size)+ "  Limit = " + QString::number(limit);
        msgBox1.setText(tmp);
        msgBox1.setDefaultButton(QMessageBox::Ok);
        int ret = msgBox1.exec();
#endif
}


HeadlineWidget::HeadlineWidget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::HeadlineWidget)
{
    Q_INIT_RESOURCE(resources);

#ifdef Q_OS_SYMBIAN
     //lock orientation
    CAknAppUi* appUi = dynamic_cast<CAknAppUi*>(CEikonEnv::Static()->AppUi());
    if(appUi){
        QT_TRAP_THROWING(appUi ->SetOrientationL(CAknAppUi::EAppUiOrientationLandscape));
   }
#endif

    ui->setupUi(this);

    _swipeGesture=new MySwipeGesture(this);

    this->setStyleSheet("background-color: rgb(52, 195, 76);");
    ui->lcdNumber->display("00:00:00");
    ui->label->setText(sharedData::currentHeadline.name);

    connect(ui->lcdNumber,SIGNAL(beYellow()),this,SLOT(setYellow()));
    connect(ui->lcdNumber,SIGNAL(beRed()),this,SLOT(setRed()));
    connect(ui->lcdNumber,SIGNAL(jstBeGreen()),this,SLOT(jstSetGreen()));
    connect(ui->lcdNumber,SIGNAL(closeNote()),this,SLOT(isClosed()));
    connect(ui->lcdNumber,SIGNAL(setLabelText()),this,SLOT(setText()));
    connect(_swipeGesture,SIGNAL(handleSwipe(MySwipeGesture::SwipeDirection)),this,SLOT(swipe(MySwipeGesture::SwipeDirection)));
    connect(ui->lcdNumber,SIGNAL(headlineTimeChanged()),this,SLOT(setLCD_2()));
    connect(ui->exit,SIGNAL(isClicked()),SLOT(isClosed()));
}
void HeadlineWidget::setText()
{
    ui->label->setText(sharedData::currentHeadline.name);
    ui->label->repaint();
}

void HeadlineWidget::setLCD_2()
{
    ui->lcdNumber_2->display(sharedData::headlineTimeString);
}

void HeadlineWidget::showButton()
{

}

void HeadlineWidget::jstSetGreen()
{
    ui->label->setText(sharedData::currentHeadline.name);
    this->setStyleSheet("background-color: rgb(52, 195, 76);");
    this->repaint();
}

void HeadlineWidget::setYellow()
{
    ui->label->setText(sharedData::currentHeadline.name);
    this->setStyleSheet("background-color: rgb(255, 217, 0);");
    this->repaint();
}

void HeadlineWidget::setRed()
{
    ui->label->setText(sharedData::currentHeadline.name);
    this->setStyleSheet("background-color: rgb(255, 0, 0);");
    this->repaint();
}

void HeadlineWidget::goNext()
{
    this->setStyleSheet("background-color: rgb(52, 195, 76);");
    this->repaint();

    sharedData::currentHeadline.time=sharedData::remainingList.at(sharedData::headlineIndex);
    sharedData::currentNote.headlines.takeAt(sharedData::headlineIndex);
    sharedData::currentNote.headlines.insert(sharedData::headlineIndex,sharedData::currentHeadline);

    //Auto calculation
    if(sharedData::autoCal && sharedData::currentHeadline.time<0)
    {
        int totalRemaining=0;
        for(int i=sharedData::headlineIndex+1;i<sharedData::remainingList.count();i++)
        {
            totalRemaining+= sharedData::remainingList.at(i);
        }

        for(int i=sharedData::headlineIndex+1;i<sharedData::remainingList.count();i++)
        {
           int newTime= sharedData::remainingList.at(i)- (float)(((float)sharedData::remainingList.at(i)/(float)totalRemaining)*(float)abs(sharedData::currentHeadline.time));
           sharedData::remainingList.takeAt(i);
           sharedData::remainingList.insert(i,newTime);

           headline newHead=sharedData::currentNote.headlines.at(i);
           newHead.time=newTime;
           sharedData::currentNote.headlines.takeAt(i);
           sharedData::currentNote.headlines.insert(i,newHead);
        }
    }

    if(sharedData::headlineIndex<sharedData::currentNote.headlines.count()-1)
        sharedData::headlineIndex++;
    sharedData::currentHeadline=sharedData::currentNote.headlines.at(sharedData::headlineIndex);
    sharedData::headlineStartTime=QTime::currentTime();

    ui->label->setText(sharedData::currentHeadline.name);
    ui->label->repaint();
}

void HeadlineWidget::isClosed()
{

    QMessageBox msgBox;
    msgBox.setText("Are you sure you want to close this talk and go to talks page?");
    msgBox.setIcon(QMessageBox::Question);
    msgBox.setStandardButtons(QMessageBox::Ok | QMessageBox::Cancel);
    msgBox.setDefaultButton(QMessageBox::Ok);
    int ret = msgBox.exec();

    if(ret==QMessageBox::Ok)
    {
        #ifdef Q_OS_SYMBIAN

            // lock orientation
            CAknAppUi* appUi = dynamic_cast<CAknAppUi*>(CEikonEnv::Static()->AppUi());
            if(appUi){
                QT_TRAP_THROWING(appUi ->SetOrientationL(CAknAppUi::EAppUiOrientationPortrait));
            }
        #endif
        this->close();
        updateHeapStats();
    }
}

HeadlineWidget::~HeadlineWidget()
{
    delete ui;
}

MySwipeGesture::MySwipeGesture(QObject *parent)
    :QObject(parent),_startPoint(0,0),_endPoint(0,0)
{}

void MySwipeGesture::handleEvent( QEvent *event)
{
    if( event->type() == QEvent::MouseButtonPress ) {
    QMouseEvent* mouseEvent = static_cast<QMouseEvent*> (event);
        _startPoint = mouseEvent->pos();
    } else if( event->type() == QEvent::MouseButtonRelease ) {
    QMouseEvent* mouseEvent = static_cast<QMouseEvent*> (event);
        _endPoint = mouseEvent->pos();

        //process distance and direction
        int xDiff = _startPoint.x() - _endPoint.x();
        int yDiff = _startPoint.y() - _endPoint.y();
        if( qAbs(xDiff) > qAbs(yDiff) && qAbs(xDiff)>120 ) {
            // horizontal swipe detected, now find direction
            if( _startPoint.x() > _endPoint.x() ) {
                emit handleSwipe( Left);
            } else {
                emit handleSwipe( Right);
            }
        } else {
            // vertical swipe detected, now find direction
            if( _startPoint.y() > _endPoint.y() && qAbs(yDiff)<10 ) {
                emit handleSwipe( Up);
            } else {
                emit handleSwipe( Down);
            }
        }
    } else if( event->type() == QEvent::MouseMove ) {
        //ignore event
    }
}

bool HeadlineWidget::event(QEvent *event)
{
    _swipeGesture->handleEvent(event);
    return QWidget::event(event);
}

void HeadlineWidget::swipe(MySwipeGesture::SwipeDirection direction)
{
    if(direction==MySwipeGesture::Left)
    {
        this->goNext();
    }
    else if(direction==MySwipeGesture::Right)
    {
        this->goPrev();
    }
    else
    {
        //click
        //showButton();
    }
}

void HeadlineWidget::goPrev()
{
    sharedData::currentHeadline.time=sharedData::remainingList.at(sharedData::headlineIndex);
    sharedData::currentNote.headlines.takeAt(sharedData::headlineIndex);
    sharedData::currentNote.headlines.insert(sharedData::headlineIndex,sharedData::currentHeadline);

    if(sharedData::headlineIndex>0)
        sharedData::headlineIndex--;
    sharedData::currentHeadline=sharedData::currentNote.headlines.at(sharedData::headlineIndex);
    sharedData::headlineStartTime=QTime::currentTime();

    ui->label->setText(sharedData::currentHeadline.name);
    ui->label->repaint();
}

[danhicksbyron]

The thing to do is to output the numbers after each operation, eg, after each rotation. You can either put a button on your UI to do this manually or trigger it from an event filter that listens for the resize event on your layout.

Then watch to see if the numbers increase steadily after each operation.