QVariant to QBitArray

Anticross

After next code:
@QHashIterator<QString, QVariant> iter(props);

                while(iter.hasNext()) {
                    iter.next();
                    
                    QString property = iter.key();

                    if (property.startsWith("mus")) {
                        int num = QString("%1").arg(property.remove("mus")).toInt();
                        QBitArray bitValue = iter.value().toBitArray();

                        m_address = sender;
                        m_socket->bind(m_address, 0x6358);
                        connect(m_socket, SIGNAL(readyRead()), this, SLOT(onReadyRead()));

                        if (num > 0 && num <= m_musList.count()) {
                            MusWidget * musWg = m_musList.at(num-1);
                            if (musWg)
                                musWg->changeState(bitValue);
                        }
                    }
                }@

I've got an empty bit array with zero size in bitValue variable. But if I look debug information of my IDE I can see that iter.value() contains some data in format of bits like "11111". So question how can I convert QVariant value to QBitArray value ?

guziemic

Hi,

I am not an expert in this area, but maybe this will help

did you try to check what type is stored by
"QVariant:Type":http://qt-project.org/doc/qt-4.8/qvariant.html#type
and if type is different maybe you could cast your Variant to desired type with "QVarian:convert":http://qt-project.org/doc/qt-4.8/qvariant.html#convert

I am not sure if Qt cast Variant to BitArray automatically.

BR,

MuldeR

QVariant::toBitArray() is correct way - given the QVariant really contains a QBitArray object.

Are you sure you have a QBitArray inside your QVariant? Maybe it's a QByteArray or something different.

In any case, you should check QVariant::typeName() to see what it actually is...

Anticross

It's a string value inserted inside which now stored in QHash iter.value(). So i need to convert from string but now it's type is QVariant. Something like this.

guziemic

Do I understand correctly that you are trying to achieve such conversion
String -> QVariant -> QBitArray

AFAIK you will be not able to make such conversion.

Anticross

I mean I insert string value into hash QHash<QString,QVariant>, but this string has format of bits "1111" or "1010" or any other binary value. After that I need to read value from hash and thats why I get QVarant value and after that I need to convert this QVariant value tu QBitArray.

guziemic

Well, if you have those bits in String then maybe better solution is to convert String to unsigned int and then with bitwise operators extract bits values.

Anticross

I can convert to int: @iter.value().toString().toInt(NULL,2)@ but how now I can insert integer value in QBitArray ?

guziemic

The snippet below shows how you can convert some integer value to bitArray. It is small main so you can run it and test.

@
#include <QBitArray>
#include <QDebug>

int main(int argc, char *argv[])
{
int someVal = 10; //value to convert
QBitArray bitArray(sizeof(int)*8);
long long refVal = 1;

//check in loop which bit is set
for ( int i = 0; i < static_cast<int>(sizeof(int)*8); i++)
{
qDebug() << "i" << i << "refVal" << refVal;

    if (false != (someVal & refVal))
    {
        bitArray.setBit(i, true);
    }

    refVal <<= 1;
}

//display bit array
for ( int i = 0; i < bitArray.size(); i++)
{
qDebug() << "Bit at i" << i << " value = "<< bitArray.at(i);
}

return 0;

@

Hope it will help