我正在使用QAbstractListModel将数据公开给QML ListView。除此之外还使用QML SectionScroller,它使用get和data函数。
经过一段时间的滚动后,会遇到崩溃。回溯是:
Program received signal SIGILL, Illegal instruction.
0x0000cdcc in QBasicAtomicInt::ref (
this=0x35)
at /usr/include/QtCore/qatomic_armv6.h:119
119 /usr/include/QtCore/qatomic_armv6.h: No such file or directory.
in /usr/include/QtCore/qatomic_armv6.h
(gdb) bt
#0 0x0000cdcc in QBasicAtomicInt::ref (
this=0x35)
at /usr/include/QtCore/qatomic_armv6.h:119
#1 0x0000f4e8 in QString (
this=0xbebf1a5c, other=...)
at /usr/include/QtCore/qstring.h:729
#2 [address] in IrregularVerb::getForm0
(this=0x92e428) at IrregularVerb.h:16
#3 0x0000e29c in IrregularListWrapper::data (this=0x92dd20, index=..., role=33)
at IrregularListWrapper.cpp:37
#4 0x4010e9c6 in ?? ()
from /usr/lib/libQtDeclarative.so.4
#5 0x4010e9c6 in ?? ()
from /usr/lib/libQtDeclarative.so.4
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
在其他设备上(首先是N900,第二个N950),回溯类似。这是SIGSEGV而不是SIGILL,但旁边的回溯是相同的。我注意到曾经有一段时间,一些场地在撞车的那一刻变得空白。 (使用getForm0和getForm1的那些)
当我添加额外的分配时,对于返回的值,崩溃发生在分配上。
一些重要的代码:
元素:
class IrregularVerb : public QObject
{
Q_OBJECT
Q_PROPERTY(QString form0 READ getForm0 CONSTANT)
Q_PROPERTY(QString form1 READ getForm1 CONSTANT)
Q_PROPERTY(QString form2 READ getForm2 CONSTANT)
public:
QString forms[3];
QString getForm0() const { return forms[0]; }
QString getForm1() const { return forms[1]; }
QString getForm2() const { return forms[2]; }
IrregularVerb(QString a, QString b, QString c) { forms[0] = a; forms[1] = b; forms[2] = c; }
};
模特:
class IrregularListWrapper : public QAbstractListModel
{
Q_OBJECT
Q_PROPERTY(QString langName READ getLangName NOTIFY langChanged)
Q_PROPERTY(int count READ rowCount NOTIFY langChanged)
Q_ENUMS(Language)
public:
Q_INVOKABLE int rowCount(const QModelIndex& = QModelIndex()) const { return db->count(); }
Q_INVOKABLE QObject* get(int index) const {return db->at(index);}
QVariant data(const QModelIndex &index, int role) const;
enum Language
{
English = 0,
German = 1
};
enum IrregularVerbRoles
{
Form0Role = Qt::UserRole + 1,
Form1Role,
Form2Role
};
IrregularListWrapper();
QString getLangName() const { return langName; }
Q_INVOKABLE void changeLang(Language l) { beginResetModel(); db = 0; setLang(l); endResetModel(); }
static QMap<Language, QString> plugins;
signals:
void langChanged();
protected:
void setLang(Language);
QString langName;
AbstractIrregularList * db;
};
QVariant IrregularListWrapper::data(const QModelIndex &index, int role) const
{
if (!index.isValid()) return QVariant();
int rowno = index.row();
qDebug() << "Row is " << index.row() << flush;
const IrregularVerb* verb = db->at(index.row());
switch (role)
{
case Form0Role:
return verb->getForm0();
break;
case Form1Role:
return verb->getForm1();
break;
case Form2Role:
return verb->getForm2();
break;
}
return QVariant();
}
AbstractIrregularList:
class AbstractIrregularList : public QObject, public QList<IrregularVerb*>
{
Q_OBJECT
public:
void IV(const char* a, const char* b, const char* c) { append (new IrregularVerb(a, b, c)); }
void IV(const char *a, const char *b) { IV(a, b, b); }
void IV(const char *a) { IV(a,a,a); }
};
Q_DECLARE_INTERFACE(AbstractIrregularList, "com.marmistrz.Plugin.AbstractIrregularList/1.0");
你知道为什么会这样吗?谢谢!
/ edit1:谢谢你的回复。这样可以吗?
Q_INVOKABLE QObject* get(int index)
{
QObject* item = db->at(index);
QDeclarativeEngine::setObjectOwnership(item, QDeclarativeEngine::CppOwnership);
item->setParent(this); // do I need to do this? An QList<QObject*>-child would clean it, right?
return item;
}
由于
答案 0 :(得分:5)
看起来你有一个&#34;经典&#34;在QML端使用QAbstractListModel
的问题。您的IrregularListWrapper
具有get
方法,该方法返回具有JS所有权的对象(该类所有权是Q_INVOKABLE
方法的默认值),并且它们将在QML端使用JS引擎进行垃圾收集。为了防止这种情况,你应该改变对象&#39;在使用QDeclarativeEngine::setObjectOwnership
将其返回QML之前的所有权。请参阅我的回答here中的示例。