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40
41 //! [0]
42 class AppendText : public QUndoCommand
43 {
44 public:
AppendText(QString * doc,const QString & text)45 AppendText(QString *doc, const QString &text)
46 : m_document(doc), m_text(text) { setText("append text"); }
undo()47 virtual void undo()
48 { m_document->chop(m_text.length()); }
redo()49 virtual void redo()
50 { m_document->append(m_text); }
51 private:
52 QString *m_document;
53 QString m_text;
54 };
55 //! [0]
56
57
58 //! [1]
59 MyCommand *command1 = new MyCommand();
60 stack->push(command1);
61 MyCommand *command2 = new MyCommand();
62 stack->push(command2);
63
64 stack->undo();
65
66 MyCommand *command3 = new MyCommand();
67 stack->push(command3); // command2 gets deleted
68 //! [1]
69
70
71 //! [2]
72 QUndoCommand *insertRed = new QUndoCommand(); // an empty command
73 insertRed->setText("insert red text");
74
75 new InsertText(document, idx, text, insertRed); // becomes child of insertRed
76 new SetColor(document, idx, text.length(), Qt::red, insertRed);
77
78 stack.push(insertRed);
79 //! [2]
80
81
82 //! [3]
mergeWith(const QUndoCommand * other)83 bool AppendText::mergeWith(const QUndoCommand *other)
84 {
85 if (other->id() != id()) // make sure other is also an AppendText command
86 return false;
87 m_text += static_cast<const AppendText*>(other)->m_text;
88 return true;
89 }
90 //! [3]
91
92
93 //! [4]
94 stack.beginMacro("insert red text");
95 stack.push(new InsertText(document, idx, text));
96 stack.push(new SetColor(document, idx, text.length(), Qt::red));
97 stack.endMacro(); // indexChanged() is emitted
98 //! [4]
99
100
101 //! [5]
102 QUndoCommand *insertRed = new QUndoCommand(); // an empty command
103 insertRed->setText("insert red text");
104
105 new InsertText(document, idx, text, insertRed); // becomes child of insertRed
106 new SetColor(document, idx, text.length(), Qt::red, insertRed);
107
108 stack.push(insertRed);
109 //! [5]
110