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50
51 //! [0]
52 class AppendText : public QUndoCommand
53 {
54 public:
AppendText(QString * doc,const QString & text)55 AppendText(QString *doc, const QString &text)
56 : m_document(doc), m_text(text) { setText("append text"); }
undo()57 void undo() override
58 { m_document->chop(m_text.length()); }
redo()59 void redo() override
60 { m_document->append(m_text); }
61 private:
62 QString *m_document;
63 QString m_text;
64 };
65 //! [0]
66
67
68 //! [1]
69 MyCommand *command1 = new MyCommand();
70 stack->push(command1);
71 MyCommand *command2 = new MyCommand();
72 stack->push(command2);
73
74 stack->undo();
75
76 MyCommand *command3 = new MyCommand();
77 stack->push(command3); // command2 gets deleted
78 //! [1]
79
80
81 //! [2]
82 QUndoCommand *insertRed = new QUndoCommand(); // an empty command
83 insertRed->setText("insert red text");
84
85 new InsertText(document, idx, text, insertRed); // becomes child of insertRed
86 new SetColor(document, idx, text.length(), Qt::red, insertRed);
87
88 stack.push(insertRed);
89 //! [2]
90
91
92 //! [3]
mergeWith(const QUndoCommand * other)93 bool AppendText::mergeWith(const QUndoCommand *other)
94 {
95 if (other->id() != id()) // make sure other is also an AppendText command
96 return false;
97 m_text += static_cast<const AppendText*>(other)->m_text;
98 return true;
99 }
100 //! [3]
101
102
103 //! [4]
104 stack.beginMacro("insert red text");
105 stack.push(new InsertText(document, idx, text));
106 stack.push(new SetColor(document, idx, text.length(), Qt::red));
107 stack.endMacro(); // indexChanged() is emitted
108 //! [4]
109
110
111 //! [5]
112 QUndoCommand *insertRed = new QUndoCommand(); // an empty command
113 insertRed->setText("insert red text");
114
115 new InsertText(document, idx, text, insertRed); // becomes child of insertRed
116 new SetColor(document, idx, text.length(), Qt::red, insertRed);
117
118 stack.push(insertRed);
119 //! [5]
120