Reading/writing QTableWidget

[Salazaar]

Hi. I've got a question. If there's no pointers to read/write to file a QTableWidget, how can I do it? Regards

[wysota]

What do you mean by "write a QTableWidget to a file"?

[Salazaar]

I have a QTableWidget in my program, and I want to save to file/read from file what it contains. Clear, now?

[fedcer]

If you look at the QTableWidget documentation (http://doc.trolltech.com/4.3/qtablewidget.html) you'll see that there is a QTableWidgetItem item(int row, int column) function. So, you could easily iterate through all the cells with loops such as these:

QTextStream out(&file);
for (int i = 0; i < rowCount(); ++i) {
    if (i > 0)
    out << '\n';
    for (int j = 0; j < columnCount(); ++j) {
       if (j > 0)
          out << '\t';
       QTableWidgetItem *cell = item(i, j);
       out << cell->text();
    }
}

QTextStream out(&file);
for (int i = 0; i < rowCount(); ++i) {
    if (i > 0)
    out << '\n';
    for (int j = 0; j < columnCount(); ++j) {
       if (j > 0)
          out << '\t';
       QTableWidgetItem *cell = item(i, j);
       out << cell->text();
    }
}

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this is just an example in which the program writes to a stream the contents of the table, separating each row with a newline and each column of each row with a tab.
To read from that same stream the code would be:

QTextStream in(&file);
QString str = in.readAll();
QStringList rows = str.split('\n');
 
int numRows = rows.count();
int numColumns = rows.first().count('\t') + 1;
setRowCount(numRows);
setColumnCount(numColumns);
 
for (int i = 0; i < numRows; ++i) {
    QStringList columns = rows[i].split('\t');
    for (int j = 0; j < numColumns; ++j) {
       QTableWidgetItem *cell = item(i, j);
       cell->setText(columns[j]);
    }
}

QTextStream in(&file);
QString str = in.readAll();
QStringList rows = str.split('\n');

int numRows = rows.count();
int numColumns = rows.first().count('\t') + 1;
setRowCount(numRows);
setColumnCount(numColumns);

for (int i = 0; i < numRows; ++i) {
    QStringList columns = rows[i].split('\t');
    for (int j = 0; j < numColumns; ++j) {
       QTableWidgetItem *cell = item(i, j);
       cell->setText(columns[j]);
    }
}

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This is just an example taken from old code I had. You should adapt it to the format in which you prefer to store the data, which could even be in binary.

[jacek]

Please, don't give fish to Salazaar.

[wysota]

Please, don't give fish to Salazaar.

Tell him "search the forum before asking questions" instead

[Salazaar]

Please, don't give fish to Salazaar.

Don't give fishes? Till I cried, though When I saw the exact code, and didn't see the other nick, I was very surprised that you're giving me code, not saying "Look at the docs" - not I'm a bit smarter than before, an firstable I'm looking at docs - when there's no answer at this question or I don't understand, I'm asking here Regards

[wysota]

You shouldn't be looking at the docs. You should be reading it

[Salazaar]

Sure But in this code that fedcer posted, there's no definition which of few QTableWidgets (if I have few) will be wrote or read. There's only QTableWidgetItem but what if I have few QTableWidgets? Regards

[wysota]

But in this code that fedcer posted, there's no definition which of few QTableWidgets (if I have few) will be wrote or read.

Sure there is. I don't have trouble determining which widget will be processed - it's the one pointed by "this"

@fedcer: That's why giving the code was a bad idea... Now you have to explain it

[fedcer]

As wysota said it's the QTableWidget poited by "this". The example code I posted was designed to work as a member of a Subclass of QTableWidget. If you want to work from outside you have to specify the QTableWidget you are referring to by calling QTableWidget's specific functions (rowCount(), columnCount(), item(), setRowCount(), setColumnCount(), ...) as member of that table. That is, in fact, the only way it could work if you decide to use that function from outside.
For example, the writing code rewritten would be:

QTableWidget table1;
QTextStream out(&file);
for (int i = 0; i < table1.rowCount(); ++i) {
    if (i > 0)
       out << '\n';
    for (int j = 0; j < table1.columnCount(); ++j) {
       if (j > 0)
          out << '\t';
       QTableWidgetItem *cell = table1.item(i, j);
       out << cell->text();
    }
}

QTableWidget table1;
QTextStream out(&file);
for (int i = 0; i < table1.rowCount(); ++i) {
    if (i > 0)
       out << '\n';
    for (int j = 0; j < table1.columnCount(); ++j) {
       if (j > 0)
          out << '\t';
       QTableWidgetItem *cell = table1.item(i, j);
       out << cell->text();
    }
}

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[Salazaar]

That's what I like. Full, clear explanation of a problem Thanks,
but there are errors that rowCount and columnCount are undeclared, do I have to declare them before?
Regards