Porting from QT4.6 to QT5

Christian Ehrlicher

You're using the wrong uic (the one from Qt4) as it seems. Make sure to recreate your Makefiles with qmake for Qt5!

SGaist

One more thing, ensure that your source tree doesn't contain any generated file e.g. ui_*.h, etc. only original sources, .qrc, .ui file etc.

Qt Enthusiast

I am getting following error

how to solve this error

QString myString
error: 'class QString' has no member named 'toAscii'
execute(myString.toAscii();

mrjj

@Qt-Enthusiast
Its in the docs. i linked before.
https://wiki.qt.io/Transition_from_Qt_4.x_to_Qt5#toAscii.28.29_and_fromAscii.28.29_Methods_are_deprecated

Qt Enthusiast

One more question, I am getting following errors

void myClass::mythod() {
bool x = FALSE;
booly = TRUE;
}

error: 'FALSE' was not declared in this scope

any reason why and how to solve this issue

is there FALSE is declared in qt4 source code

mrjj

@Qt-Enthusiast
just use the c++ versions
true
false
(in small letters)

Qt Enthusiast

what is significance of FALSE and TRUE in Qt4

Qt Enthusiast

Also I am getting an error
mainwindow.h:17:0: error: "Q_NULLPTR" redefined [-Werror]

is Q_NULLPTR defined in SRC of QT5

jsulm

@Qt-Enthusiast Please post your code (mainwindow.h).
Also it is better to use nullptr from C++11 now.

Qt Enthusiast

@mrjj
is FALSE and TRUE defined in qt4 code

JKSH

@Qt-Enthusiast said in Porting from QT4.6 to QT5:

is FALSE and TRUE defined in qt4 code

No.

Qt Enthusiast

Then why I am getting this error when I am changing the library to Qt5

jsulm

@Qt-Enthusiast Do you use same compiler for both Qt versions?

JKSH

@Qt-Enthusiast said in Porting from QT4.6 to QT5:

Then why I am getting this error when I am changing the library to Qt5

Because you also changed your compiler?

Qt Enthusiast

@jsulm

Yes
I changed just the qt version. What is significance of Q_NULLPTR

jsulm

@Qt-Enthusiast Well, if you search a bit you will find this in Qt source:

#ifdef Q_COMPILER_NULLPTR
# define Q_NULLPTR         nullptr
#else
# define Q_NULLPTR         NULL
#endif

If you have a C++11 compiler Q_NULLPTR will be nullptr, else it will be the old C/C++ NULL.
You can use Q_NULLPTR if you have to support older C++ compilers which do not know anything about nullptr and newer C++ compilers.

Qt Enthusiast

how to solve the following error

error: no matching function for call to 'QGraphicsTextItem::QGraphicsTextItem(const char [5], int, QGraphicsScene*&)'
cursor = new QGraphicsTextItem("0, 0", 0, scene);

jsulm

@Qt-Enthusiast Go here and check what constructors QGraphicsTextItem has: http://doc.qt.io/qt-5/qgraphicstextitem.html

Qt Enthusiast

Hi
I saw
http://doc.qt.io/qt-5/qgraphicsscene.html

QGraphicsItem * itemAt(const QPointF &position, const QTransform &deviceTransform) const
QGraphicsItem * itemAt(qreal x, qreal y, const QTransform &deviceTransform) const

buit still could not find the correct fix for compliation error

What const QTransform &deviceTransform shall I use

error: no matching function for call to 'QGraphicsScene::itemAt(QPointF&)'
QPointF m ;
QGraphicsItem *currentItem = scene->itemAt(m);

jsulm

@Qt-Enthusiast http://doc.qt.io/qt-5/qgraphicsscene.html#itemAt has two parameters not one.
Try to pass QTransform() as second parameter.