QScrollBar & QSlider & QDial

Posted 2020-10-06 kaizen

【1】滚动条 & 滑块 & 表盘

Qt示例工程：

（1）slidergroup.h

 1 #include <QGroupBox>
 2 
 3 QT_BEGIN_NAMESPACE
 4 class QDial;
 5 class QScrollBar;
 6 class QSlider;
 7 QT_END_NAMESPACE
 8 
 9 class SlidersGroup : public QGroupBox
10 {
11     Q_OBJECT
12 
13 public:
14     SlidersGroup(Qt::Orientation orientation,
15                  const QString &title,
16                  QWidget *parent = 0);
17 
18 signals:
19     void valueChanged(int value);
20 
21 public slots:
22     void setValue(int value);
23     void setMinimum(int value);
24     void setMaximum(int value);
25     void invertAppearance(bool invert);
26     void invertKeyBindings(bool invert);
27 
28 private:
29     QSlider *m_pSlider;
30     QScrollBar *m_pScrollBar;
31     QDial *m_pDial;
32 };
33 
34 #endif

（2）slidergroup.cpp

 1 #include <QtWidgets>
 2 #include "SlidersGroup.h"
 3 
 4 SlidersGroup::SlidersGroup(Qt::Orientation orientation,
 5                            const QString &title,
 6                            QWidget *parent)
 7     : QGroupBox(title, parent)
 8 {
 9     m_pSlider = new QSlider(orientation, this);
10     m_pSlider->setFocusPolicy(Qt::StrongFocus);
11     m_pSlider->setTickPosition(QSlider::TicksBothSides);
12     m_pSlider->setTickInterval(10);
13     m_pSlider->setSingleStep(1);
14 
15     m_pScrollBar = new QScrollBar(orientation, this);
16     m_pScrollBar->setFocusPolicy(Qt::StrongFocus);
17 
18     m_pDial = new QDial(this);
19     m_pDial->setFocusPolicy(Qt::StrongFocus);
20 
21     connect(m_pSlider, &QSlider::valueChanged, m_pScrollBar, &QScrollBar::setValue);
22     connect(m_pScrollBar, &QScrollBar::valueChanged, m_pDial, &QDial::setValue);
23     connect(m_pDial, &QDial::valueChanged, m_pSlider, &QSlider::setValue);
24     connect(m_pDial, &QDial::valueChanged, this, &SlidersGroup::valueChanged);
25 
26     QBoxLayout::Direction direction = (Qt::Horizontal == orientation) ? QBoxLayout::TopToBottom : QBoxLayout::LeftToRight;
27 
28     QBoxLayout *m_pSlidersLayout = new QBoxLayout(direction, this);
29     m_pSlidersLayout->addWidget(m_pSlider);
30     m_pSlidersLayout->addWidget(m_pScrollBar);
31     m_pSlidersLayout->addWidget(m_pDial);
32     setLayout(m_pSlidersLayout);
33 }
34 
35 void SlidersGroup::setValue(int value)
36 {
37     m_pSlider->setValue(value);
38 }
39 
40 void SlidersGroup::setMinimum(int value)
41 {
42     m_pSlider->setMinimum(value);
43     m_pScrollBar->setMinimum(value);
44     m_pDial->setMinimum(value);
45 }
46 
47 void SlidersGroup::setMaximum(int value)
48 {
49     m_pSlider->setMaximum(value);
50     m_pScrollBar->setMaximum(value);
51     m_pDial->setMaximum(value);
52 }
53 
54 void SlidersGroup::invertAppearance(bool invert)
55 {
56     m_pSlider->setInvertedAppearance(invert);
57     m_pScrollBar->setInvertedAppearance(invert);
58     m_pDial->setInvertedAppearance(invert);
59 }
60 
61 void SlidersGroup::invertKeyBindings(bool invert)
62 {
63     m_pSlider->setInvertedControls(invert);
64     m_pScrollBar->setInvertedControls(invert);
65     m_pDial->setInvertedControls(invert);
66 }

（3）window.h

 1 #ifndef WINDOW_H
 2 #define WINDOW_H
 3 
 4 #include <QWidget>
 5 
 6 QT_BEGIN_NAMESPACE
 7 class QCheckBox;
 8 class QComboBox;
 9 class QGroupBox;
10 class QLabel;
11 class QSpinBox;
12 class QStackedWidget;
13 QT_END_NAMESPACE
14 class SlidersGroup;
15 
16 class Window : public QWidget
17 {
18     Q_OBJECT
19 
20 public:
21     Window();
22 
23 private:
24     QSpinBox *createSpinBox();
25     void createControls(const QString &title);
26 
27 private:
28     SlidersGroup *m_pHorizontalSliders;
29     SlidersGroup *m_pVerticalSliders;
30     QStackedWidget *m_pStackedWidget;
31 
32     QGroupBox *m_pControlsGroup;
33     QLabel *m_pMinimumLabel;
34     QLabel *m_pMaximumLabel;
35     QLabel *m_pValueLabel;
36     QCheckBox *m_pInvertedAppearance;
37     QCheckBox *m_pInvertedKeyBindings;
38     QSpinBox *m_pMinimumSpinBox;
39     QSpinBox *m_pMaximumSpinBox;
40     QSpinBox *m_pValueSpinBox;
41     QComboBox *m_pOrientationCombo;
42 };
43 
44 #endif

（4）window.cpp

 1 #include <QtWidgets>
 2 
 3 #include "slidersgroup.h"
 4 #include "window.h"
 5 
 6 Window::Window()
 7 {
 8     m_pHorizontalSliders = new SlidersGroup(Qt::Horizontal, tr("Horizontal"), this);
 9     m_pVerticalSliders = new SlidersGroup(Qt::Vertical, tr("Vertical"), this);
10 
11     m_pStackedWidget = new QStackedWidget(this);
12     m_pStackedWidget->addWidget(m_pHorizontalSliders);
13     m_pStackedWidget->addWidget(m_pVerticalSliders);
14 
15     createControls(tr("Controls"));
16 
17     connect(m_pHorizontalSliders, &SlidersGroup::valueChanged,
18             m_pVerticalSliders, &SlidersGroup::setValue);
19     connect(m_pVerticalSliders, &SlidersGroup::valueChanged,
20             m_pValueSpinBox, &QSpinBox::setValue);
21     typedef void (QSpinBox::*valueChangedInt)(int);
22     connect(m_pValueSpinBox, static_cast<valueChangedInt>(&QSpinBox::valueChanged),
23             m_pHorizontalSliders, &SlidersGroup::setValue);
24 
25     QHBoxLayout *pHLayout = new QHBoxLayout(this);
26     pHLayout->addWidget(m_pControlsGroup);
27     pHLayout->addWidget(m_pStackedWidget);
28     setLayout(pHLayout);
29 
30     m_pMinimumSpinBox->setValue(0);
31     m_pMaximumSpinBox->setValue(20);
32     m_pValueSpinBox->setValue(5);
33 
34     setWindowTitle(tr("MySliders"));
35 }
36 
37 void Window::createControls(const QString &title)
38 {
39     m_pControlsGroup = new QGroupBox(title, this);
40 
41     m_pMinimumLabel = new QLabel(tr("Minimum value:"), this);
42     m_pMaximumLabel = new QLabel(tr("Maximum value:"), this);
43     m_pValueLabel = new QLabel(tr("Current value:"), this);
44 
45     m_pInvertedAppearance = new QCheckBox(tr("Inverted appearance"), this);
46     m_pInvertedKeyBindings = new QCheckBox(tr("Inverted key bindings"), this);
47 
48     m_pMinimumSpinBox = createSpinBox();
49     m_pMaximumSpinBox = createSpinBox();
50     m_pValueSpinBox = createSpinBox();
51 
52     m_pOrientationCombo = new QComboBox(this);
53     m_pOrientationCombo->addItem(tr("Horizontal slider-like widgets"));
54     m_pOrientationCombo->addItem(tr("Vertical slider-like widgets"));
55 
56     typedef void (QComboBox::*activatedInt)(int);
57     connect(m_pOrientationCombo, static_cast<activatedInt>(&QComboBox::activated),
58             m_pStackedWidget, &QStackedWidget::setCurrentIndex);
59     typedef void (QSpinBox::*valueChangedInt)(int);
60     connect(m_pMinimumSpinBox, static_cast<valueChangedInt>(&QSpinBox::valueChanged),
61             m_pHorizontalSliders, &SlidersGroup::setMinimum);
62     connect(m_pMinimumSpinBox, static_cast<valueChangedInt>(&QSpinBox::valueChanged),
63             m_pVerticalSliders, &SlidersGroup::setMinimum);
64     connect(m_pMaximumSpinBox, static_cast<valueChangedInt>(&QSpinBox::valueChanged),
65             m_pHorizontalSliders, &SlidersGroup::setMaximum);
66     connect(m_pMaximumSpinBox, static_cast<valueChangedInt>(&QSpinBox::valueChanged),
67             m_pVerticalSliders, &SlidersGroup::setMaximum);
68     connect(m_pInvertedAppearance, &QCheckBox::toggled,
69             m_pHorizontalSliders, &SlidersGroup::invertAppearance);
70     connect(m_pInvertedAppearance, &QCheckBox::toggled,
71             m_pVerticalSliders, &SlidersGroup::invertAppearance);
72     connect(m_pInvertedKeyBindings, &QCheckBox::toggled,
73             m_pHorizontalSliders, &SlidersGroup::invertKeyBindings);
74     connect(m_pInvertedKeyBindings, &QCheckBox::toggled,
75             m_pVerticalSliders, &SlidersGroup::invertKeyBindings);
76 
77     QGridLayout *pControlsLayout = new QGridLayout(this);
78     pControlsLayout->addWidget(m_pMinimumLabel, 0, 0);
79     pControlsLayout->addWidget(m_pMaximumLabel, 1, 0);
80     pControlsLayout->addWidget(m_pValueLabel, 2, 0);
81     pControlsLayout->addWidget(m_pMinimumSpinBox, 0, 1);
82     pControlsLayout->addWidget(m_pMaximumSpinBox, 1, 1);
83     pControlsLayout->addWidget(m_pValueSpinBox, 2, 1);
84     pControlsLayout->addWidget(m_pInvertedAppearance, 0, 2);
85     pControlsLayout->addWidget(m_pInvertedKeyBindings, 1, 2);
86     pControlsLayout->addWidget(m_pOrientationCombo, 3, 0, 1, 3);
87     m_pControlsGroup->setLayout(pControlsLayout);
88 }
89 
90 QSpinBox* Window::createSpinBox()
91 {
92     QSpinBox *pValueSpinBox = new QSpinBox(this);
93     pValueSpinBox->setRange(-100, 100);
94     pValueSpinBox->setSingleStep(1);
95     return pValueSpinBox;
96 }

（5）main.cpp

 1 #include <QApplication>
 2 #include "window.h"
 3 
 4 int main(int argc, char *argv[])
 5 {
 6     QApplication app(argc, argv);
 7     Window window;
 8     window.show();
 9     return app.exec();
10 }

注意：代码已很简洁，没有再加注释。

【2】运行效果

水平滚动条：

垂直滚动条：

 

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