Getting the text from a QTextEdit inside a QWidget

Question

I have a QTabWidget 'tw' to which I add tabs like this:

QWidget *newTab = new QWidget(tw);
tw->addTab(newTab, "Tab name");
QTextEdit *te = new QTextEdit();
te->setText("Hello world");
QVBoxLayout *vbox = new QVBoxLayout();
vbox->addWidget(te);
newTab->setLayout(vbox);

How can I get the text inside the QTextEdit from the tab that is in the foreground (like when I click a button I'd like to copy the text from the visible tab to the clipboard or smtg like that). I don't know how to get a handle of the QTextEdit.

Answer 1

You need to keep track of your text edits manually. Either through storing a pointer to them in a parent widget, or you could make use of a lookup table, e.g. a QHash:

Assuming you have a class MyClass which contains the code you posted in your question:

Add a member variable like this:

class QTextEdit; // this is a so-called "Forward Declaration" which saves you an
                 // #include. Google it if you want to know more ;-)
class MyClass
{
    // ...
private:

    QHash< int, QTextEdit* > _textEditPerTabPage;
};

This variable makes it possible to store (and find) the text edit from the index (0, 1, 2, ...) of your tab pages.

You could do an add function like this:

void MyClass::addTab( QTabWidget* tabWidget, const QString& tabName, const QString& text )
{
    // Create the text edit
    QTextEdit* textEdit = new QTextEdit();
    textEdit->setText( text );

    // Create a layout which contains the text edit
    QVBoxLayout* layout = new QVBoxLayout();
    layout->addWidget( textEdit );

    // Create a parent widget for the layout
    QWidget* newTab = new QWidget( tabWidget );
    newTab->setLayout( layout );

    // Add that widget as a new tab
    int tabIndex = tabWidget->addTab( newTab, tabName );

    // Remember the text edit for the widget
    _textEditPerTabPage.insert( tabIndex, textEdit );
}

And then retrieve a pointer on the QTextEdit like this:

QTextEdit* textEdit = _textEditPerTabPage.value( tabWidget->currentIndex() );

This code has a couple of limitations, e.g. you always have to make sure you use your own MyClass::addTab function and don't access QTabWidget::addTab outside of that function. Also if you call QTabWidget::removeTab, your QHash may no longer point to the proper QTextEdits.