about custom widget plugins

[hesummar]

Hello,everyone. My Qt version is Qt3.3 . I have a problem,when I copy the "filechooser" example in Qt designer manual , run on my machine . I can find "libfilechooser.so" plugin in my /usr/lib/qt3/plugins/designer directory . but in Qt designer, I can't find that widget . Help me please , thank you!

[wysota]

You have probably built it against a debug version of Qt and Designer uses release version of the library. Rebuild the plugin in release mode.

[hesummar]

Hello wysota,How to build Qt sources in release mode ?

[wysota]

Add CONFIG+=release to the project file and make sure there is no CONFIG+=debug there. As for Qt itself, if you didn't compile it from scratch it should already be in release mode. If not, pass -release to configure and recompile.

[hesummar]

Hello wysota . This is my *.pro file:
INCLUDEPATH += .

# Input
HEADERS += filechooser.h plugin.h
SOURCES += filechooser.cpp plugin.cpp

TEMPLATE = lib
LANGUAGE = C++
TARGET = filechooser

DESTDIR = $(QTDIR)/plugins/designer

target.path=$(QTDIR)/plugins/designer

INSTALLS += target
CONFIG += qt warn_on release plugin
DBFILE = plugin.db
I don't know why ,as if my Qt designer can't see the "/usr/lib/qt3/plugins/designer/libfilechooser.so" plugin,can you tell me how can I do?

[jacek]

Try adding CONFIG += thread to your .pro file.

[hesummar]

It is still have this problem,Can someone give me a example? Thank you! hesummar@126.com

[jacek]

It is still have this problem

Did you add "CONFIG += thread" to your plugin's .pro file and recompiled it?

[hesummar]

Yes , really . My operation system is suse linux 10.1 .

[jacek]

Maybe Qt Designer doesn't look for plugins in that directory? Check "Plugin Paths" in Edit -> Preferences.

[hesummar]

I found that the Qt designer didn't look for plugins in that directory , after I edited the plugins paths , The Qt designer still didn't see that plugins , Please give me an example .

[jacek]

Add Q_OBJECT macro to CustomWidgetPlugin definition.

[hesummar]

In my file ,it already had this macro , but i found that in the Qt designer manual the example about create custom widget example is different from the one in <<c++ programming with Qt3>>. In the Qt designer manual the example has QT_WIDGET_PLUGIN_EXPORT macro , but the one in <<c++ programming with Qt3>> doesn't have . Can you tell me why? and please give me an example whitch one can work very well in your machine .

[sunil.thaha]

Well to give you a simple answer !!
This is a link (http://www.wysota.eu.org/wwwidgets/ ) to the widget made by wysota. Why don't you try downloading those and see if it loads properly in designer ? And if it does, You can compare and see what is wrong.

[jacek]

In my file ,it already had this macro , but i found that in the Qt designer manual the example about create custom widget example is different from the one in <<c++ programming with Qt3>>.

The code for that example is available in $QTDIR/tools/designer/examples/filechooser/. To make it work on my system I had to add CONFIG += thread to plugin.pro file, Q_OBJECT macro to CustomWidgetPlugin class and a proper path to Qt Designer (note that if you add /some/path/plugins to "Plugin Paths" in Qt Designer, it will look for the plugin in /some/path/plugins/designer). Also try running Qt Designer from the console --- it might output some message explaining what's wrong.

In the Qt designer manual the example has QT_WIDGET_PLUGIN_EXPORT macro , but the one in <<c++ programming with Qt3>> doesn't have . Can you tell me why?

It's only relevant on windows where you have to export classes explicitly. Ask Google about __declspec(dllimport) and __declspec(dllexport).

[arnaiz]

Hi hesummar:

I have a similar problem in qt 3.3.4 with designer 3.3.4. Even when the path was added with qtconfig, and apparently accepted by designer, my plugins did'nt work.

I found out that, at least with my version of qt, if the plugin lib was in a directory different from the one in qt3 tree (/usr/lib/qt3/plugins/designer/), the plugin was not recognized by designer.

¿Have you tried puting the plugin in that directory?

Bye.

[hesummar]

Thank you ! I found that the plugins in http://www.wysota.eu.org/wwwidgets/ could work very well in my machine . I will check where was wrong .