Problem using setPixmap on a label

[ciclonite]

Hi all,
sorry for disturb.. I' m a very newbie with Qt and the C++ isn't my primary programming language..
I've a problem when i try to change the pixmap from a slot function:
Here the code :

Nopaste

Thanks a lot,
Giovanni

[SGaist]

Hi and welcome to devnet,

Look your constructor again: you have shadowed your class member variable with local version. So when you call e.g. on_ResistenzeOn_clicked you are setting an uninitialized pixmap on your label.

[ciclonite]

Hi,
Thanks for reply, i've looked my constructor but i cannot find the problem.. Sorry! Where have i shadowed my class member with local version? In the constructor i've initialized the QPixmap with relative image.
Thanks for patience.

[SGaist]

From your constructor with comments:

ui->setupUi(this);
QPixmap fire(":/images/Fire.png");
QPixmap fireScaled = fire.scaled(QSize(131,121),Qt::KeepAspectRatio); // << Shadowing your class member fireScaled
QPixmap cold(":/images/cold.png");
QPixmap coldScaled = cold.scaled(QSize(131,121),Qt::KeepAspectRatio); // << Shadowing your class member coldeScaled

[ciclonite]

SGaist : Sorry i'm a noob...
Only the last question. I've solved the problem but i wish to know if this is trash code:
On mainwindow.h i've declared :
QPixmap *fire;
QPixmap fireScaled;
QPixmap *cold;
QPixmap coldScaled;

On mainwindow.c :
ui->setupUi(this);
fire = new QPixmap(":/images/Fire.png");
fireScaled = fire->scaled(QSize(131,121),Qt::KeepAspectRatio);
cold = new QPixmap(":/images/cold.png");
coldScaled = cold->scaled(QSize(131,99),Qt::KeepAspectRatio);
QPixmap tempDown(":/images/tempdown.png");

Many thanks for your help and your patience.

[SGaist]

First thing: you almost never need to allocated a QPixmap (or QImage for that matter) on the heap.
Second thing: since you only use fire and cold in the constructor it doesn't make sense to keep them.
Last thing: don't forget to handle properly the deletion of stuff you allocate on the heap.

[ciclonite]

Thanks a lot SGaist, problem solved!! :)