QCachece accessing problem

[rajini333]

When accessing the QCache that time my application is crashing...

Just i downloaded one image and inserted into QCache table.

Then i am getting some downloaded images from other class and inserted in QCache table.

Now i am trying to access the QCache table using Keys(URL link).. That time application is crashing ,even the corresponding key values is in tables also...

if i access the first images,what i stored from this class only..That image i am getting ..

When accessing the another class images,which is stored in QCache..that time application is crashing..

Code for downloading the image at same class

void Widget::imageGet( const QString url )
{
static int i =0;
 i++;
 qDebug() << i;
  if(!imageCache.contains(url))
 {
      QPixmap yu;
     imageCache.insert(url,NULL);
    QUrl  _url = QUrl(url);
    buffer->open(QIODevice::ReadWrite);
    qDebug() << "url link is " << url;
    http->setHost(_url.host());
    qDebug() << "not same url";
    http_id = http->get(_url.path(), buffer);
    requestByEntry.insert(url,http_id);
}
}
void Widget::request(int id, bool error)
{
 
    if(error) return;
    if(http_id == id && http->lastResponse().statusCode() == 200)
    {
        QPixmap image ;
        QByteArray imagedata = buffer->data();
        image.loadFromData(imagedata);
 
            imageCache.insert(requestByEntry.key(id),&image);
            ui->userpiclabel->setPixmap(*imageCache[URL]);
        QPixmap yu;
        yu = *imageCache[URL];
 
QString str ="yuvaraj";
QString str1 ="text";
Tweet *f = new Tweet(str,str1,yu);
   buffer->close();
    }
}

void Widget::imageGet( const QString url )
{
static int i =0;
 i++;
 qDebug() << i;
  if(!imageCache.contains(url))
 {
      QPixmap yu;
     imageCache.insert(url,NULL);
    QUrl  _url = QUrl(url);
    buffer->open(QIODevice::ReadWrite);
    qDebug() << "url link is " << url;
    http->setHost(_url.host());
    qDebug() << "not same url";
    http_id = http->get(_url.path(), buffer);
    requestByEntry.insert(url,http_id);
}
}
void Widget::request(int id, bool error)
{

    if(error) return;
    if(http_id == id && http->lastResponse().statusCode() == 200)
    {
        QPixmap image ;
        QByteArray imagedata = buffer->data();
        image.loadFromData(imagedata);

            imageCache.insert(requestByEntry.key(id),&image);
            ui->userpiclabel->setPixmap(*imageCache[URL]);
        QPixmap yu;
        yu = *imageCache[URL];

QString str ="yuvaraj";
QString str1 ="text";
Tweet *f = new Tweet(str,str1,yu);
   buffer->close();
    }
}

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Getting images from other class . I checked this images is not null

void Widget::getimage(QString string,QPixmap image)
{
    if(!image.isNull())
    {
        if(!imageCache.contains(string))
        {
    qDebug() << "image got";
    imageCache.insert(string,&image);
 
    qDebug() << "Hash Table size:" << imageCache.size();
 
}
}
}

void Widget::getimage(QString string,QPixmap image)
{
    if(!image.isNull())
    {
        if(!imageCache.contains(string))
        {
    qDebug() << "image got";
    imageCache.insert(string,&image);
   
    qDebug() << "Hash Table size:" << imageCache.size();

}
}
}

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Accessing the images from QCache

void Widget::DisplayList(QLinkedList<Returnables::StatusUser*> list, QString header)
{
    Returnables::StatusUser *statusUser = NULL;
    model = new QStandardItemModel(this);
    for(int i=0;i<list.size();i++)
    {   QStandardItem *item = new QStandardItem;
        model->appendRow(item);
    }
  qDebug() <<" Running at second for loop";
    ui->listView_2->setModel(model);
    static int j = list.size();
 
    for(int i=0;i<j;i++)
    {
 
     qDebug() <<"Hello friends";
     statusUser = list.takeFirst();
    QString url =statusUser->user.profileImageUrl;
    QString name = statusUser->user.name;
    QString text = statusUser->status.text;
    qDebug() << "imageCache size :" <<imageCache.size();
     qDebug() << url ;
    if(imageCache[url] == NULL)
    {
 
    QPixmap rr;
   // qDebug()<<"image  null";
   rr = *imageCache[URL];
    qDebug()<<"image  null0";
    qDebug() << "hi hello";
Tweet *t =new Tweet(name,text,rr);
      t->resize(490,90);
       model->item(i)->setSizeHint(t->size());
       ui->listView_2->setIndexWidget(model->item(i)->index(), t);
    qDebug()<<"i Am for loop";
    }
    if(imageCache[url] != NULL)
    {
        QString url1 = statusUser->user.profileImageUrl;
        qDebug() << url;
        qDebug()<<"image is not  null";
        qDebug() << imageCache.keys();
        qDebug() << "url link:"<< url1;
    QPixmap yy;
      yy = *imageCache.take(url);
        qDebug() << "image assigned";
  Tweet *t =new Tweet(name,text,yy);
       t->resize(490,90);
         model->item(i)->setSizeHint(t->size());
          ui->listView_2->setIndexWidget(model->item(i)->index(), t);
 
    }
}
}

void Widget::DisplayList(QLinkedList<Returnables::StatusUser*> list, QString header)
{
    Returnables::StatusUser *statusUser = NULL;
    model = new QStandardItemModel(this);
    for(int i=0;i<list.size();i++)
    {   QStandardItem *item = new QStandardItem;
        model->appendRow(item);
    }
  qDebug() <<" Running at second for loop";
    ui->listView_2->setModel(model);
    static int j = list.size();
  
    for(int i=0;i<j;i++)
    {

     qDebug() <<"Hello friends";
     statusUser = list.takeFirst();
    QString url =statusUser->user.profileImageUrl;
    QString name = statusUser->user.name;
    QString text = statusUser->status.text;
    qDebug() << "imageCache size :" <<imageCache.size();
     qDebug() << url ;
    if(imageCache[url] == NULL)
    {

    QPixmap rr;
   // qDebug()<<"image  null";
   rr = *imageCache[URL];
    qDebug()<<"image  null0";
    qDebug() << "hi hello";
Tweet *t =new Tweet(name,text,rr);
      t->resize(490,90);
       model->item(i)->setSizeHint(t->size());
       ui->listView_2->setIndexWidget(model->item(i)->index(), t);
    qDebug()<<"i Am for loop";
    }
    if(imageCache[url] != NULL)
    {
        QString url1 = statusUser->user.profileImageUrl;
        qDebug() << url;
        qDebug()<<"image is not  null";
        qDebug() << imageCache.keys();
        qDebug() << "url link:"<< url1;
    QPixmap yy;
      yy = *imageCache.take(url);
        qDebug() << "image assigned";
  Tweet *t =new Tweet(name,text,yy);
       t->resize(490,90);
         model->item(i)->setSizeHint(t->size());
          ui->listView_2->setIndexWidget(model->item(i)->index(), t);
     
    }
}
}

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when compiler is coming at line of assigning the images from image Cache[url] that time application is crashing...

I hope some one might help us


Thanks

Yuvaraj R

[wysota]

Creating three different users at the forum is not a very good idea if you want people to help you. This tends to make some of us annoyed...

As for the question - you are storing a pointer to a local object in the cache. Hence when the object runs out of scope you end up with an invalid pointer which you try to access later on.