Style Plugin Example does not show red Button

[samdol]

Hi,

I have run Style Plugin Example in Qt5.6
But I don't see the red button. Is it a bug?
I am using Windows 7.

[mrjj]

hi
Most likely the plugin dll was not copied to the right folder.
This seems to be QTDIR/plugins/styles but not sure as I never made a Style plugin.
Its not a bug with the sample as such.

http://doc.qt.io/qt-5/plugins-howto.html

[samdol]

@mrjj
Thanks,
I found that the plugins at
C:...\styleplugin\release\styles\libsimplestyleplugin.a
C:...\styleplugin\release\styles\simplestyleplugin.dll
Isn't it the right location?
The excutable was created in
C:...\styleplugin\release\styleplugin.exe
But still I don't see the red button.
I also put libsimplestyleplugin.a and simplestyleplugin.dll to
QTDIR/plugins/styles
but I could not see the red button.

[mrjj]

@samdol said in Style Plugin Example does not show red Button:

simplestyleplugin.dll

Hi , i think it needs to be placed in predefined folder unless the sample
uses other means to load it.

[samdol]

@mrjj
Does predefined folder mean QTDIR/plugins/styles?
I also put libsimplestyleplugin.a and simplestyleplugin.dll to there, but it did not make any change.
I used Qt windows binary version.
Do I have to compile Qt itself to use plugin?

[mrjj]

@samdol said in Style Plugin Example does not show red Button:

QTDIR/plugins/styles

Yes I think so. I have not tried a Style plugin but it was the same with designer plugin.
Should be placed in right folder.
It should be clear from reading the docs.

Update:
The sample says
"We set the library to be stored in the styles folder under stylewindow because this is a path in which Qt will search for style plugins."
So maybe it looks there.

[SGaist]

Hi,

You should also add QT_DEBUG_PLUGINS=1 to the environment variables in the Run part of the project panel. That should give you more clues about why it doesn't load.

[samdol]

@SGaist
Thanks, I put qputenv("QT_DEBUG_PLUGINS", QByteArray("1")); before
QApplication app(argv, args); in main(). And I got the following output,
It seems it loaded the simplestyleplugin.dll. I don't understand why it checks
C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/accessible which I don't have. And it
says libsimplestyleplugin.a is not a plugin. I heard that .a is a static
library. This example is for dynamic plugin. I have no idea why I created a
static library.

QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms" ...
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qminimal.dll"
Found metadata in lib C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qminimal.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimal"
        ]
    },
    "className": "QMinimalIntegrationPlugin",
    "debug": false,
    "version": 329218
}
Got keys from plugin meta data ("minimal")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qminimald.dll"
Found metadata in lib C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qminimald.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimal"
        ]
    },
    "className": "QMinimalIntegrationPlugin",
    "debug": true,
    "version": 329218
}


"The plugin 'C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qminimald.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qoffscreen.dll"
Found metadata in lib C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qoffscreen.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "offscreen"
        ]
    },
    "className": "QOffscreenIntegrationPlugin",
    "debug": false,
    "version": 329218
}
Got keys from plugin meta data ("offscreen")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qoffscreend.dll"
Found metadata in lib C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qoffscreend.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "offscreen"
        ]
    },
    "className": "QOffscreenIntegrationPlugin",
    "debug": true,
    "version": 329218
}


"The plugin 'C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qoffscreend.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qwindows.dll"
Found metadata in lib C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qwindows.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "windows"
        ]
    },
    "className": "QWindowsIntegrationPlugin",
    "debug": false,
    "version": 329218
}
Got keys from plugin meta data ("windows")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qwindowsd.dll"
Found metadata in lib C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qwindowsd.dll, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "windows"
        ]
    },
    "className": "QWindowsIntegrationPlugin",
    "debug": true,
    "version": 329218
}


"The plugin 'C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qwindowsd.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release/platforms" ...
loaded library "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platforms/qwindows.dll"
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/platformthemes" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release/platformthemes" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/styles" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release/styles" ...
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release/styles/libsimplestyleplugin.a"
"Failed to extract plugin meta data from 'C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release/styles/libsimplestyleplugin.a'"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release/styles/simplestyleplugin.dll"
Found metadata in lib C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release/styles/simplestyleplugin.dll, metadata=
{
    "IID": "org.qt-project.Qt.QStyleFactoryInterface",
    "MetaData": {
        "Keys": [
            "simplestyle"
        ]
    },
    "className": "SimpleStylePlugin",
    "debug": false,
    "version": 329218
}
Got keys from plugin meta data ("simplestyle")
loaded library "C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release/styles/simplestyleplugin.dll"
currentdir:  "C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release"
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/accessible" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release/accessible" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.6.2/5.6/mingw49_32/plugins/accessiblebridge" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release/accessiblebridge" ...

[SGaist]

From this line: loaded library "C:/Qt/build-styleplugin-Desktop_Qt_5_6_2_MinGW_32bit-Release/release/styles/simplestyleplugin.dll" it looks like it has been loaded, no ?

[samdol]

@SGaist
I think so. But I don't see the red button somehow.