1 #include <QtWidgets>
2 //自定义item需要重写的两个函数boudingRect()和paint()
3 class CheckBoxItem : public QGraphicsObject
4 {
5 Q_OBJECT
6 public:
7 CheckBoxItem(int w, int h, const QString &text, const QString &checkedIcon, const QString &emptyIcon, QGraphicsObject *parent = 0);
8 QRectF boundingRect()const override; //用来设置该item的大小 必须
9 void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) override;//用来绘制该item的东西 必须
10 bool isChecked();
11 void setChecked(bool checked);
12 signals:
13 void stateChanged(bool checked);
14 protected:
15 void keyPressEvent(QKeyEvent * event) override;
16 void mousePressEvent(QGraphicsSceneMouseEvent *event) override;
17 void mouseReleaseEvent(QGraphicsSceneMouseEvent *event) override;
18 private:
19 QString m_text;
20 int m_width;
21 int m_height;
22 bool m_checked;
23 QPixmap m_checkedIcon;
24 QPixmap m_emptyIcon;
25 bool m_leftButtonDown;
26 };
27
28 CheckBoxItem::CheckBoxItem(int w, int h, const QString &text, const QString &checkedIcon, const QString &emptyIcon, QGraphicsObject *parent) :
29 m_width(w),
30 m_height(h),
31 m_text(text),
32 m_checkedIcon(checkedIcon),
33 m_emptyIcon(emptyIcon),
34 QGraphicsObject(parent), m_leftButtonDown(false)
35 {
36 setFlag(QGraphicsItem::ItemIsFocusable, true); //用来设置这个item可以获取焦点
37 }
38 QRectF CheckBoxItem::boundingRect() const
39 {
40 return QRectF(0,0, m_width, m_height);
41 }
42 //调用这里面的painter画家进行绘制图形
43 void CheckBoxItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
44 {
45 Q_UNUSED(option)
46 Q_UNUSED(widget)//这个宏是用来把不用到的参数注掉的功能
47 int x = 2;
48 int y = (m_height - m_checkedIcon.height()) / 2;
49 painter->drawPixmap(x, y, m_checked ? m_checkedIcon : m_emptyIcon);
50 if(!m_text.isEmpty())
51 {
52 x = x + m_checkedIcon.width() + 4;
53 QRect rc(x, 0, m_width - x - 2, m_height);
54 painter->drawText(rc, Qt::AlignVCenter | Qt::AlignLeft, m_text);
55 }
56 }
57 void CheckBoxItem::keyPressEvent(QKeyEvent *event)
58 {
59 if(event->key() == Qt::Key_Space)
60 {
61 event->accept();
62 m_checked = !m_checked;
63 update();
64 }
65 }
66 void CheckBoxItem::mousePressEvent(QGraphicsSceneMouseEvent *event)
67 {
68 if(event->button() == Qt::LeftButton)
69 {
70 m_leftButtonDown = true;
71 event->accept();
72 }
73 }
74 void CheckBoxItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
75 {
76 if(event->button() == Qt::LeftButton)
77 {
78 m_leftButtonDown = false;
79 m_checked = !m_checked;
80 event->accept();
81 update();
82 emit stateChanged(m_checked);
83 }
84 }
