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//! [0]
class AppendText : public QUndoCommand
{
public:
AppendText(QString *doc, const QString &text)
: m_document(doc), m_text(text) { setText("append text"); }
virtual void undo()
{ m_document->chop(m_text.length()); }
virtual void redo()
{ m_document->append(m_text); }
private:
QString *m_document;
QString m_text;
};
//! [0]
//! [1]
MyCommand *command1 = new MyCommand();
stack->push(command1);
MyCommand *command2 = new MyCommand();
stack->push(command2);
stack->undo();
MyCommand *command3 = new MyCommand();
stack->push(command3); // command2 gets deleted
//! [1]
//! [2]
QUndoCommand *insertRed = new QUndoCommand(); // an empty command
insertRed->setText("insert red text");
new InsertText(document, idx, text, insertRed); // becomes child of insertRed
new SetColor(document, idx, text.length(), Qt::red, insertRed);
stack.push(insertRed);
//! [2]
//! [3]
bool AppendText::mergeWith(const QUndoCommand *other)
{
if (other->id() != id()) // make sure other is also an AppendText command
return false;
m_text += static_cast<const AppendText*>(other)->m_text;
return true;
}
//! [3]
//! [4]
stack.beginMacro("insert red text");
stack.push(new InsertText(document, idx, text));
stack.push(new SetColor(document, idx, text.length(), Qt::red));
stack.endMacro(); // indexChanged() is emitted
//! [4]
//! [5]
QUndoCommand *insertRed = new QUndoCommand(); // an empty command
insertRed->setText("insert red text");
new InsertText(document, idx, text, insertRed); // becomes child of insertRed
new SetColor(document, idx, text.length(), Qt::red, insertRed);
stack.push(insertRed);
//! [5]
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