Hello,

I am trying to write my first plasmoid in PyQt but when I try to view it in plasmaviewer it crashes with segmentation fault "Executable: plasmoidviewer PID: 23063 Signal: 11 (Segmentation fault)", here's the log:

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~/Develop/Python/plasmoids> plasmoidviewer qt-converter.plasmoid
plasmoidviewer(23614)/plasma main: setting FormFactor to "planar"
plasmoidviewer(23614)/plasma main: setting Location to "floating"
plasmoidviewer(23614)/plasma main: setting containment to "null"
plasmoidviewer(23614)/plasma main: setting auth policy
plasmoidviewer(23614)/plasma main: just load applet
plasmoidviewer(23614)/plasma FullView::addApplet: adding applet
"qt-converter.plasmoid" in "null"
plasmoidviewer(23614)/libplasma Plasma::CoronaPrivate::addContainment: loading
of containment "null" failed.
plasmoidviewer(23614)/kdecore (KSycoca): Trying to open ksycoca from 
"/var/tmp/kdecache-linuxoid/ksycoca4"
plasmoidviewer(23614)/libplasma Plasma::AppletPrivate::init: Check your
constructor!  You probably want to be passing in a Service::Ptr  or a
QVariantList with a valid storageid as arg[0].
plasmoidviewer(23614)/python (plugin)
KPythonPluginFactory::KPythonPluginFactory:
KPythonPluginFactory::KPythonPluginFactory()
plasmoidviewer(23614)/python (plugin) KPythonPluginFactory::initialize:
Initializing Python interpreter.
plasmoidviewer(23614)/python (plugin) KPythonPluginFactory::initialize:
Succesfully initialized Python interpreter.
plasmoidviewer(23614)/python (plugin) KPythonPluginFactory::create:
KPythonPluginFactory::create iface:  Plasma::AppletScript
plasmoidviewer(23614)/python (plugin) KPythonPluginFactory::create: keyword to
be used for finding the plugin code: 
"plasma_scriptengine_python/pyappletscript.py"
plasmoidviewer(23614)/python (plugin) KPythonPluginFactory::create: Path to
plugin code is: 
"/usr/share/kde4/apps/plasma_scriptengine_python/pyappletscript.py"
plasmoidviewer(23614)/python (plugin) KPythonPluginFactory::create: Returning
result qobject
plasmoidviewer(23614)/libplasma Plasma::AppletPrivate::setupScriptSupport:
setting up script support, package is in
"/home/linuxoid/Develop/Python/plasmoids/qt-converter.plasmoid/" which is a
"Plasmoid" package , main script is
"/home/linuxoid/Develop/Python/plasmoids/qt-converter.plasmoid/contents/code/main.py"
plasmoidviewer(23614)/libplasma Plasma::Package::filePath:
"/home/linuxoid/Develop/Python/plasmoids/qt-converter.plasmoid/contents/locale"
does not exist
plasmoidviewer(23614)/libplasma Plasma::Package::filePath:
"/home/linuxoid/Develop/Python/plasmoids/qt-converter.plasmoid/contents/config/main.xml"
 does not exist
plasmoidviewer(23614)/libplasma Plasma::Package::filePath:
"/home/linuxoid/Develop/Python/plasmoids/qt-converter.plasmoid/contents/ui/config.ui"
 does not exist
KCrash: Application 'plasmoidviewer' crashing...
sock_file=/home/linuxoid/.kde4/socket-linuxoid/kdeinit4__0

[1]+  Stopped                 plasmoidviewer qt-converter.plasmoid


Here's my main.py file below. I have a stand alone application and it works fine. It must be something to do with plasma. What am I doing wrong? Will greatly appreciate your help. Thank you.

Code:

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# -*- coding: utf-8 -*-

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from PyKDE4.plasma import Plasma
from PyKDE4 import plasmascript
 
class PyQtConverter(plasmascript.Applet):
    def __init__(self,parent,args=None):
        plasmascript.Applet.__init__(self,parent)
 
    def init(self):
        self.setHasConfigurationInterface(False)
        self.setAspectRatioMode(Plasma.Square)
 
        self.theme = Plasma.Svg(self)
        self.theme.setImagePath("widgets/background")
        self.setBackgroundHints(Plasma.Applet.DefaultBackground)

        self.mainWidget = QWidget()
        self.scene = QGraphicsScene()
        self.mainGraphicsWidget = self.scene.addWidget(self.mainWidget)

        self.btnSize = QSize(50, 50)
        self.iconSize = QSize(40, 40)
       
        self.iconFind = QIcon(":/myresources/icons/search.svg")
        self.iconCheck = QIcon(":/myresources/icons/check.svg")
        self.iconAbout = QIcon(":/myresources/icons/about.svg")

        sizePolicy = QSizePolicy(QSizePolicy.Minimum, QSizePolicy.Fixed)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
       
        self.btnCheck = QPushButton(self.iconCheck, "", self.mainWidget)
        self.btnCheck.setIconSize(self.iconSize)
       
        sizePolicy.setHeightForWidth(self.btnCheck.sizePolicy().hasHeightForWidth())
        self.btnCheck.setSizePolicy(sizePolicy)
        self.btnCheck.setMinimumSize(self.btnSize)
        self.btnFind = QPushButton(self.iconFind, "", self.mainWidget)
        self.btnFind.setIconSize(self.iconSize)
       
        sizePolicy.setHeightForWidth(self.btnFind.sizePolicy().hasHeightForWidth())
        self.btnFind.setSizePolicy(sizePolicy)
        self.btnFind.setMinimumSize(self.btnSize)
        self.btnAbout = QPushButton(self.iconAbout, "", self.mainWidget)
        self.btnAbout.setIconSize(self.iconSize)
       
        sizePolicy.setHeightForWidth(self.btnAbout.sizePolicy().hasHeightForWidth())
        self.btnAbout.setSizePolicy(sizePolicy)
        self.btnAbout.setMinimumSize(self.btnSize)
       
        self.hbToolbar = QHBoxLayout()
        self.hbToolbar.sizeConstraint = QLayout.SetDefaultConstraint
        self.hbToolbar.addWidget(self.btnCheck)
        self.hbToolbar.addWidget(self.btnFind)
        self.hbToolbar.addWidget(self.btnAbout)
       
        self.mainLayout = QVBoxLayout(self.mainWidget)
        self.mainLayout.sizeConstraint = QLayout.SetDefaultConstraint
        self.mainLayout.addLayout(self.hbToolbar)

        self.layout = QGraphicsLinearLayout(Qt.Horizontal, self.applet)
        self.layout.addItem(self.mainGraphicsWidget)
       
        self.applet.setLayout(self.layout)
        self.resize(125,125)

 
def CreateApplet(parent):
    return PyQtConverter(parent)


Have you tried generating a backtrace using Dr Konqi?

Sorry, i'm new to this. Can you please repeat this in english? What's a backtrace and who's Dr Konqi?

When the application you are using to test your Plasmoid, "plasmoidviewer" crashes, the Crash Assistant should start and if you select the "Developer Information" tab it will generate a backtrace which can be used to find the cause of the crash.

Here it is:

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Application: Plasma Widget Viewer (plasmoidviewer), signal: Segmentation fault
[KCrash Handler]
#5  0x00007fb837d3abc7 in QGraphicsItemPrivate::setParentItemHelper(QGraphicsItem*, QVariant const*, QVariant const*) () from /usr/lib64/libQtGui.so.4
#6  0x00007fb837d3b1da in QGraphicsItem::setParentItem(QGraphicsItem*) () from /usr/lib64/libQtGui.so.4
#7  0x00007fb837d55e44 in QGraphicsLinearLayout::insertItem(int, QGraphicsLayoutItem*) () from /usr/lib64/libQtGui.so.4
#8  0x00007fb81d7db003 in ?? () from /usr/lib64/python2.6/site-packages/PyQt4/QtGui.so
#9  0x00007fb81e63fbf9 in PyEval_EvalFrameEx () from /usr/lib64/libpython2.6.so.1.0
#10 0x00007fb81e640194 in PyEval_EvalFrameEx () from /usr/lib64/libpython2.6.so.1.0
#11 0x00007fb81e64454e in PyEval_EvalCodeEx () from /usr/lib64/libpython2.6.so.1.0
#12 0x00007fb81e5e27f2 in ?? () from /usr/lib64/libpython2.6.so.1.0
#13 0x00007fb81e5c2e32 in PyObject_Call () from /usr/lib64/libpython2.6.so.1.0
#14 0x00007fb81e5cf010 in ?? () from /usr/lib64/libpython2.6.so.1.0
#15 0x00007fb81e5c2e32 in PyObject_Call () from /usr/lib64/libpython2.6.so.1.0
#16 0x00007fb81e63dea6 in PyEval_CallObjectWithKeywords () from /usr/lib64/libpython2.6.so.1.0
#17 0x00007fb81dd19d5b in ?? () from /usr/lib64/python2.6/site-packages/sip.so
#18 0x00007fb81dfbb98c in ?? () from /usr/lib64/python2.6/site-packages/PyQt4/QtCore.so
#19 0x00007fb81d0ab212 in sipPlasma_AppletScript::init() () from /usr/lib64/python2.6/site-packages/PyKDE4/plasma.so
#20 0x00007fb838c1a4ba in Plasma::Applet::init() () from /usr/lib64/libplasma.so.3
#21 0x00007fb838c30568 in Plasma::Containment::addApplet(Plasma::Applet*, QPointF const&, bool) () from /usr/lib64/libplasma.so.3
#22 0x0000000000407059 in _start ()


The crash is caused by the following line of your Plasmoid.

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self.layout = QGraphicsLinearLayout(Qt.Horizontal, self.applet)

It crashes on this line in particular though:

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self.layout.addItem(self.mainGraphicsWidget)

I don't see self.applet used anywhere else, hence this is probably invalid, and causing the crash.

Still crashes after I removed 'self.applet':

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Application: Plasma Widget Viewer (plasmoidviewer), signal: Segmentation fault
[KCrash Handler]
#5  0x00007f0318f2cbc7 in QGraphicsItemPrivate::setParentItemHelper(QGraphicsItem*, QVariant const*, QVariant const*) () from /usr/lib64/libQtGui.so.4
#6  0x00007f0318f2d1da in QGraphicsItem::setParentItem(QGraphicsItem*) () from /usr/lib64/libQtGui.so.4
#7  0x00007f0318f45d17 in ?? () from /usr/lib64/libQtGui.so.4
#8  0x00007f0318f88295 in QGraphicsWidget::setLayout(QGraphicsLayout*) () from /usr/lib64/libQtGui.so.4
#9  0x00007f02fe9c662e in ?? () from /usr/lib64/python2.6/site-packages/PyQt4/QtGui.so
#10 0x00007f02ff831bf9 in PyEval_EvalFrameEx () from /usr/lib64/libpython2.6.so.1.0
#11 0x00007f02ff832194 in PyEval_EvalFrameEx () from /usr/lib64/libpython2.6.so.1.0
#12 0x00007f02ff83654e in PyEval_EvalCodeEx () from /usr/lib64/libpython2.6.so.1.0
#13 0x00007f02ff7d47f2 in ?? () from /usr/lib64/libpython2.6.so.1.0
#14 0x00007f02ff7b4e32 in PyObject_Call () from /usr/lib64/libpython2.6.so.1.0
#15 0x00007f02ff7c1010 in ?? () from /usr/lib64/libpython2.6.so.1.0
#16 0x00007f02ff7b4e32 in PyObject_Call () from /usr/lib64/libpython2.6.so.1.0
#17 0x00007f02ff82fea6 in PyEval_CallObjectWithKeywords () from /usr/lib64/libpython2.6.so.1.0
#18 0x00007f02fef0bd5b in ?? () from /usr/lib64/python2.6/site-packages/sip.so
#19 0x00007f02ff1ad98c in ?? () from /usr/lib64/python2.6/site-packages/PyQt4/QtCore.so
#20 0x00007f02fe29d212 in sipPlasma_AppletScript::init() () from /usr/lib64/python2.6/site-packages/PyKDE4/plasma.so
#21 0x00007f0319e0c4ba in Plasma::Applet::init() () from /usr/lib64/libplasma.so.3
#22 0x00007f0319e22568 in Plasma::Containment::addApplet(Plasma::Applet*, QPointF const&, bool) () from /usr/lib64/libplasma.so.3
#23 0x0000000000407059 in _start ()


BTW, I used this tutorial as a basis and it has 'self/applet': http://techbase.kde.org/Development/Tut ... ng_widgets

If you try running the Plasmoid code as shown in the tutorial does it work?

Yes, it does. If I display simple widgets (labels, buttons etc.), it all works fine. As soon as I start adding layouts and adding complex widgets (widgets with widgets and/or layouts), it starts crashing.

I would recommend asking in #plasma on Freenode, who should be able to help you with this.