Re: [Qt-creator] Is there a Try and Catch method in QT
On Thursday 01 July 2010 03:01:05 Diego Turcios wrote: Hi guys I thinks this is the right mailing list for my doubt. I am working on a small application in QT. But right now I have the following problem. I have a line edit, and I want to manipulate the values so only numbers (doubles) can be written on this line edit. The right way to do this in Qt is to use a validator. Just write this line in the constructor of your dialog (after setting up the ui). ui-LEPrecio-setValidator( new QDoubleValidator ); This way you are sure the user can only type a double. No need to do any check. Nicolas -- Nicolas Arnaud-Cormos | nicolas.arnaud-cor...@kdab.com | Software Engineer Klarälvdalens Datakonsult AB, a KDAB Group company Tel. Sweden (HQ) +46-563-540090, USA +1-866-777-KDAB(5322) KDAB - Qt Experts - Platform-independent software solutions ___ Qt-creator mailing list Qt-creator@trolltech.com http://lists.trolltech.com/mailman/listinfo/qt-creator
Re: [Qt-creator] Is there a Try and Catch method in QT
Catch them within the handler or in QApplication::notify()
http://strange-paradox.livejournal.com/4902.html
On Thu, Jul 1, 2010 at 2:35 AM, Coda Highland c...@bobandgeorge.com wrote:
I know this is the wrong mailing list but I will caution that Qt is
not exception-safe (and doesn't even have to be compiled with
exception support enabled) and throwing exceptions through Qt code
(for instance, in a slot or in an event handler) has negative effects.
It's possible to safely use exceptions (QtConcurrent uses them
internally for instance) but you need to make sure to catch them
before it crosses Qt code.
/s/ Adam
On Wed, Jun 30, 2010 at 8:05 PM, Carter, Nathan ncar...@bentley.edu
wrote:
This is actually the Qt-creator mailing list, not the Qt mailing list.
But
I'll answer your question anyway. In the future, though, ask Qt
questions
over there. (It's called qt-interest and shows up if you search for
that
term.)
The QString::toDouble() method does not throw an exception if it gets
text
that's not a double. Instead, it has the ok parameter to let you know
that information. See the documentation (inside Qt-creator!) for
QString::toDouble() to see how to use the ok parameter to do your test,
instead of try-catch.
But yes, the very fact that your code compiled tells you that C++ (and
hence
Qt) support try-catch structures.
Nathan
On Jun 30, 2010, at 9:01 PM, Diego Turcios wrote:
Hi guys
I thinks this is the right mailing list for my doubt.
I am working on a small application in QT. But right now I have the
following problem.
I have a line edit, and I want to manipulate the values so only numbers
(doubles) can be written on this line edit.
I was trying something like this
double quantity;
try
{
quantity=ui-LEPrecio-text().toDouble();
}
catch(QString error)
{
QMessageBox msgBox;
msgBox.setText(error);
msgBox.exec();
}
After doing this. I am planning to manipulate the double value, but this
doesn't work. If I write hello world on the line edit. Supposly it
converts
it, and it doesn't work. Any idea ;)
Diego Turcios
DiegoTc
Ubuntu User # 27518
---
Mis Blogs
http://diegoturcios.wordpress.com/
https://wiki.ubuntu.com/DiegoTurcios
--
Recuerden Dios siempre esta presente:
http://sagradocorazondejesus-diegotc.blogspot.com/
ATT1..txt
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Re: [Qt-creator] Is there a Try and Catch method in QT
- Original message - On Thursday 01 July 2010 03:01:05 Diego Turcios wrote: Hi guys I thinks this is the right mailing list for my doubt. I am working on a small application in QT. But right now I have the following problem. I have a line edit, and I want to manipulate the values so only numbers (doubles) can be written on this line edit. The right way to do this in Qt is to use a validator. Just write this line in the constructor of your dialog (after setting up the ui). ui-LEPrecio-setValidator( new QDoubleValidator ); This way you are sure the user can only type a double. No need to do any check. Note that Qt also has a QDoubleSpinBox, which is a suitable widget for entering double values. Regards, Bjorn ___ Qt-creator mailing list Qt-creator@trolltech.com http://lists.trolltech.com/mailman/listinfo/qt-creator
[Qt-creator] Is there a Try and Catch method in QT
Hi guys
I thinks this is the right mailing list for my doubt.
I am working on a small application in QT. But right now I have the
following problem.
I have a line edit, and I want to manipulate the values so only numbers
(doubles) can be written on this line edit.
I was trying something like this
double quantity;
try
{
quantity=ui-LEPrecio-text().toDouble();
}
catch(QString error)
{
QMessageBox msgBox;
msgBox.setText(error);
msgBox.exec();
}
After doing this. I am planning to manipulate the double value, but this
doesn't work. If I write hello world on the line edit. Supposly it converts
it, and it doesn't work. Any idea ;)
Diego Turcios
DiegoTc
Ubuntu User # 27518
---
Mis Blogs
http://diegoturcios.wordpress.com/
https://wiki.ubuntu.com/DiegoTurcios
--
Recuerden Dios siempre esta presente:
http://sagradocorazondejesus-diegotc.blogspot.com/
___
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Re: [Qt-creator] Is there a Try and Catch method in QT
This is actually the Qt-creator mailing list, not the Qt mailing list. But
I'll answer your question anyway. In the future, though, ask Qt questions over
there. (It's called qt-interest and shows up if you search for that term.)
The QString::toDouble() method does not throw an exception if it gets text
that's not a double. Instead, it has the ok parameter to let you know that
information. See the documentation (inside Qt-creator!) for
QString::toDouble() to see how to use the ok parameter to do your test, instead
of try-catch.
But yes, the very fact that your code compiled tells you that C++ (and hence
Qt) support try-catch structures.
Nathan
On Jun 30, 2010, at 9:01 PM, Diego Turcios wrote:
Hi guys
I thinks this is the right mailing list for my doubt.
I am working on a small application in QT. But right now I have the following
problem.
I have a line edit, and I want to manipulate the values so only numbers
(doubles) can be written on this line edit.
I was trying something like this
double quantity;
try
{
quantity=ui-LEPrecio-text().toDouble();
}
catch(QString error)
{
QMessageBox msgBox;
msgBox.setText(error);
msgBox.exec();
}
After doing this. I am planning to manipulate the double value, but this
doesn't work. If I write hello world on the line edit. Supposly it converts it,
and it doesn't work. Any idea ;)
Diego Turcios
DiegoTc
Ubuntu User # 27518
---
Mis Blogs
http://diegoturcios.wordpress.com/
https://wiki.ubuntu.com/DiegoTurcios
--
Recuerden Dios siempre esta presente:
http://sagradocorazondejesus-diegotc.blogspot.com/
ATT1..txt
___
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Re: [Qt-creator] Is there a Try and Catch method in QT
I know this is the wrong mailing list but I will caution that Qt is
not exception-safe (and doesn't even have to be compiled with
exception support enabled) and throwing exceptions through Qt code
(for instance, in a slot or in an event handler) has negative effects.
It's possible to safely use exceptions (QtConcurrent uses them
internally for instance) but you need to make sure to catch them
before it crosses Qt code.
/s/ Adam
On Wed, Jun 30, 2010 at 8:05 PM, Carter, Nathan ncar...@bentley.edu wrote:
This is actually the Qt-creator mailing list, not the Qt mailing list. But
I'll answer your question anyway. In the future, though, ask Qt questions
over there. (It's called qt-interest and shows up if you search for that
term.)
The QString::toDouble() method does not throw an exception if it gets text
that's not a double. Instead, it has the ok parameter to let you know
that information. See the documentation (inside Qt-creator!) for
QString::toDouble() to see how to use the ok parameter to do your test,
instead of try-catch.
But yes, the very fact that your code compiled tells you that C++ (and hence
Qt) support try-catch structures.
Nathan
On Jun 30, 2010, at 9:01 PM, Diego Turcios wrote:
Hi guys
I thinks this is the right mailing list for my doubt.
I am working on a small application in QT. But right now I have the
following problem.
I have a line edit, and I want to manipulate the values so only numbers
(doubles) can be written on this line edit.
I was trying something like this
double quantity;
try
{
quantity=ui-LEPrecio-text().toDouble();
}
catch(QString error)
{
QMessageBox msgBox;
msgBox.setText(error);
msgBox.exec();
}
After doing this. I am planning to manipulate the double value, but this
doesn't work. If I write hello world on the line edit. Supposly it converts
it, and it doesn't work. Any idea ;)
Diego Turcios
DiegoTc
Ubuntu User # 27518
---
Mis Blogs
http://diegoturcios.wordpress.com/
https://wiki.ubuntu.com/DiegoTurcios
--
Recuerden Dios siempre esta presente:
http://sagradocorazondejesus-diegotc.blogspot.com/
ATT1..txt
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Re: [Qt-creator] Is there a Try and Catch method in QT
One last comment -- toDouble() takes a bool* parameter to indicate
success or failure; as mentioned, Qt (except for Concurrent) doesn't
use exceptions.
/s/ Adam
On Wed, Jun 30, 2010 at 8:01 PM, Diego Turcios diegoturcio...@gmail.com wrote:
Hi guys
I thinks this is the right mailing list for my doubt.
I am working on a small application in QT. But right now I have the
following problem.
I have a line edit, and I want to manipulate the values so only numbers
(doubles) can be written on this line edit.
I was trying something like this
double quantity;
try
{
quantity=ui-LEPrecio-text().toDouble();
}
catch(QString error)
{
QMessageBox msgBox;
msgBox.setText(error);
msgBox.exec();
}
After doing this. I am planning to manipulate the double value, but this
doesn't work. If I write hello world on the line edit. Supposly it converts
it, and it doesn't work. Any idea ;)
Diego Turcios
DiegoTc
Ubuntu User # 27518
---
Mis Blogs
http://diegoturcios.wordpress.com/
https://wiki.ubuntu.com/DiegoTurcios
--
Recuerden Dios siempre esta presente:
http://sagradocorazondejesus-diegotc.blogspot.com/
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