Custom Widgets which inherits from QTreeWidget crashes while destructing? - c++

Question

Recently I've met some problems about QT.As we have a lot of custom widgets (inherit from QT's basic widgets such as QWidget,QTreeWidget...),they worked fine at runtime,BUT,IT IS EASY TO CRASH when exiting program or destructing them,I don't know IF THERE ANYTHING WRONG or inappropriate while implementing a widget which inherits from a basic widget.
Here is an example:
ChatTreeWidget.cpp:
#include "ChatTreeWidget.h"
#include <QPicture>
#include <QDebug>
ChatTreeWidget::ChatTreeWidget(QWidget *parent)
:QTreeWidget(parent)
{
setRootIsDecorated(false);
setIndentation(0);
setHeaderHidden(true);
setIconSize(QSize(30, 30));
setFocusPolicy(Qt::NoFocus);
setObjectName(QString("chatTreeWidget"));
setStyleSheet("#chatTreeWidget{border:0px;}"
"QTreeWidget::item{border-bottom:1px solid #d9d9d9;padding-left:0px;}"
"QTreeWidget::item:hover{background-color: #def0ff;}"
"QTreeWidget::item:selected{background-color:#c2e2fd;}");
connect(this, &QTreeWidget::itemExpanded, this, [=](QTreeWidgetItem *item)
{
auto indexvar = item->data(0, Qt::UserRole).toInt();
indexvar -= 10000;
if (indexvar > m_iconList.size() || indexvar < 0)
return;
auto lbl = m_iconList.at(indexvar);
lbl->setPixmap(QPixmap(":/Widgets/Resources/chattree/sanjiao1.png"));
});
connect(this, &QTreeWidget::itemCollapsed, this, [=](QTreeWidgetItem *item)
{
auto indexvar = item->data(0, Qt::UserRole).toInt();
indexvar -= 10000;
if (indexvar > m_iconList.size() || indexvar < 0)
return;
auto lbl = m_iconList.at(indexvar);
lbl->setPixmap(QPixmap(":/Widgets/Resources/chattree/sanjiao2.png"));
});
connect(this, &QTreeWidget::itemClicked, this, [=](QTreeWidgetItem *item, int column) {
auto indexvar = item->data(0, Qt::UserRole).toInt();
indexvar -= 10000;
if (indexvar > m_iconList.size() || indexvar < 0)
return;
if (item->isExpanded())
{
setItemExpanded(item, false);
}
else
{
setItemExpanded(item, true);
}
});
setVerticalScrollMode(QAbstractItemView::ScrollPerPixel);
}
ChatTreeWidget::~ChatTreeWidget()
{
qDebug() << "123123";
}
QTreeWidgetItem* ChatTreeWidget::addTreeWidgetTopItem(QString str)
{
return insertTreeWidgetTopItem(topLevelItemCount(), str);
}
QTreeWidgetItem* ChatTreeWidget::insertTreeWidgetTopItem(int index, QString str)
{
QWidget *widget = new QWidget(this);
QLabel *textLabel = new QLabel(widget);
QHBoxLayout *hlayout = new QHBoxLayout(widget);
QLabel *iconLabel = new QLabel(widget);
QSpacerItem *spacer = new QSpacerItem(20, 20, QSizePolicy::Expanding, QSizePolicy::Minimum);
textLabel->setText(str);
textLabel->setStyleSheet(u8"font-family: \"Microsoft YaHei\"");
hlayout->addWidget(textLabel);
hlayout->addSpacerItem(spacer);
iconLabel->setPixmap(QPixmap(":/Widgets/Resources/chattree/sanjiao2.png"));
hlayout->addWidget(iconLabel);
hlayout->setContentsMargins(5, 0, 10, 0);
widget->setLayout(hlayout);
m_iconList.append(iconLabel);
QTreeWidgetItem *rootItem = new QTreeWidgetItem();
rootItem->setData(0, Qt::UserRole, m_index);
rootItem->setSizeHint(0, QSize(30, 30));
m_index++;
this->insertTopLevelItem(index, rootItem);
setItemWidget(rootItem, 0, widget);
rootItem->setBackground(0, Qt::green);
setExpandsOnDoubleClick(false);
return rootItem;
}
void ChatTreeWidget::setRootItemStyleSheet(QTreeWidgetItem *item,QString css)
{
auto widgets = itemWidget(item, 0);
widgets->setStyleSheet(css);
}
void ChatTreeWidget::setRootItemStyleSheet(QString css)
{
for (qint32 i = 0; i < topLevelItemCount(); i++)
{
auto rootItem = topLevelItem(i);
auto widgets = itemWidget(rootItem,0);
widgets->setStyleSheet(css);
}
}
this code is trying to implement a custom-treewidget to display chat members,so it inherits the QTreeWidget (once I thought I should implement it with QTreeView,but as I'm stupid and lazy,I used QTreeWidget Directly),and uses a special style-sheet to change display style.and as it's a public widget,it offers some interfaces to add top-level items.there is an example image:
when I destruct this widget (I' sure that this widget is token from UI or layout) and even sometimes QT's automatic destructing will cause a crash.It happens very frequently but not everytime.
the two main ways of destroying the widget are:
1.Add it to some Ui,and let it managed by that UI.
2.delete by hand:
chatTreeWidget->setParent(0);
chatTreeWidget->disconnect();
chatTreeWidget->deleteLater();
both of them can cause a random crash.
Is there anything wrong? or it's just a bug?
Thanks for any kind of help!