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QAbstractSpinBox Class

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QAbstractSpinBox Class

  • Header: QAbstractSpinBox

  • CMake:

    find_package(Qt6 REQUIRED COMPONENTS Widgets)

    target_link_libraries(mytarget PRIVATE Qt6::Widgets)

  • qmake: QT += widgets

  • Inherits: QWidget

  • Inherited By: QDateTimeEdit, QDoubleSpinBox, and QSpinBox

  • Group: QAbstractSpinBox is part of abstractwidgets

Detailed Description

The class is designed as a common super class for widgets like QSpinBox, QDoubleSpinBox and QDateTimeEdit

Here are the main properties of the class:

  1. text: The text that is displayed in the QAbstractSpinBox.

  2. alignment: The alignment of the text in the QAbstractSpinBox.

  3. wrapping: Whether the QAbstractSpinBox wraps from the minimum value to the maximum value and vice versa.

QAbstractSpinBox provides a virtual stepBy() function that is called whenever the user triggers a step. This function takes an integer value to signify how many steps were taken. E.g. Pressing Qt::Key_Down will trigger a call to stepBy(-1).

When the user triggers a step whilst holding the Qt::ControlModifier, QAbstractSpinBox steps by 10 instead of making a single step. This step modifier affects wheel events, key events and interaction with the spinbox buttons. Note that on macOS, Control corresponds to the Command key.

Since Qt 5.12, QStyle::SH_SpinBox_StepModifier can be used to select which Qt::KeyboardModifier increases the step rate. Qt::NoModifier disables this feature.

QAbstractSpinBox also provide a virtual function stepEnabled() to determine whether stepping up/down is allowed at any point. This function returns a bitset of StepEnabled.

See Also

Member Type Documentation

 

enum QAbstractSpinBox::ButtonSymbols

This enum type describes the symbols that can be displayed on the buttons in a spin box.

Image non disponible Image non disponible

Constant

Value

Description

QAbstractSpinBox::UpDownArrows

0

Little arrows in the classic style.

QAbstractSpinBox::PlusMinus

1

+ and - symbols.

QAbstractSpinBox::NoButtons

2

Don't display buttons.

See Also

enum QAbstractSpinBox::CorrectionMode

This enum type describes the mode the spinbox will use to correct an Intermediate value if editing finishes.

Constant

Value

Description

QAbstractSpinBox::CorrectToPreviousValue

0

The spinbox will revert to the last valid value.

QAbstractSpinBox::CorrectToNearestValue

1

The spinbox will revert to the nearest valid value.

See Also

See also correctionMode

enum QAbstractSpinBox::StepEnabledFlag

flags QAbstractSpinBox::StepEnabled

Constant

QAbstractSpinBox::StepNone

0x00

QAbstractSpinBox::StepUpEnabled

0x01

QAbstractSpinBox::StepDownEnabled

0x02

The StepEnabled type is a typedef for QFlags<StepEnabledFlag>. It stores an OR combination of StepEnabledFlag values.

enum QAbstractSpinBox::StepType

Constant

QAbstractSpinBox::DefaultStepType

0

QAbstractSpinBox::AdaptiveDecimalStepType

1

Property Documentation

 

accelerated : bool

This property holds whether the spin box will accelerate the frequency of the steps when pressing the step Up/Down buttons.

If enabled the spin box will increase/decrease the value faster the longer you hold the button down.

Access functions:

  • bool isAccelerated() const

  • void setAccelerated(bool on)

[read-only] acceptableInput : const bool

This property holds whether the input satisfies the current validation

Access functions:

  • bool hasAcceptableInput() const

See Also

See also validate(), fixup(), correctionMode

alignment : Qt::Alignment

This property holds the alignment of the spin box

Possible Values are Qt::AlignLeft, Qt::AlignRight, and Qt::AlignHCenter.

By default, the alignment is Qt::AlignLeft

Attempting to set the alignment to an illegal flag combination does nothing.

Access functions:

  • alignment() const

  • void setAlignment( flag)

See Also

See also Qt::Alignment

buttonSymbols : ButtonSymbols

This property holds the current button symbol mode

The possible values can be either UpDownArrows or PlusMinus. The default is UpDownArrows.

Note that some styles might render PlusMinus and UpDownArrows identically.

Access functions:

  • buttonSymbols() const

  • void setButtonSymbols( bs)

See Also

See also ButtonSymbols

correctionMode : CorrectionMode

This property holds the mode to correct an Intermediate value if editing finishes

The default mode is QAbstractSpinBox::CorrectToPreviousValue.

Access functions:

  • correctionMode() const

  • void setCorrectionMode( cm)

See Also

See also acceptableInput, validate(), fixup()

frame : bool

This property holds whether the spin box draws itself with a frame

If enabled (the default) the spin box draws itself inside a frame, otherwise the spin box draws itself without any frame.

Access functions:

  • bool hasFrame() const

  • void setFrame(bool)

keyboardTracking : bool

This property holds whether keyboard tracking is enabled for the spinbox.

If keyboard tracking is enabled (the default), the spinbox emits the valueChanged() and textChanged() signals while the new value is being entered from the keyboard.

E.g. when the user enters the value 600 by typing 6, 0, and 0, the spinbox emits 3 signals with the values 6, 60, and 600 respectively.

If keyboard tracking is disabled, the spinbox doesn't emit the valueChanged() and textChanged() signals while typing. It emits the signals later, when the return key is pressed, when keyboard focus is lost, or when other spinbox functionality is used, e.g. pressing an arrow key.

Access functions:

  • bool keyboardTracking() const

  • void setKeyboardTracking(bool kt)

readOnly : bool

This property holds whether the spin box is read only.

In read-only mode, the user can still copy the text to the clipboard, or drag and drop the text; but cannot edit it.

The QLineEdit in the QAbstractSpinBox does not show a cursor in read-only mode.

Access functions:

  • bool isReadOnly() const

  • void setReadOnly(bool r)

See Also

[since 5.3] showGroupSeparator : bool

This property holds whether a thousands separator is enabled. By default this property is false.

This property was introduced in Qt 5.3.

Access functions:

  • bool isGroupSeparatorShown() const

  • void setGroupSeparatorShown(bool shown)

specialValueText : QString

This property holds the special-value text

If set, the spin box will display this text instead of a numeric value whenever the current value is equal to minimum(). Typical use is to indicate that this choice has a special (default) meaning.

For example, if your spin box allows the user to choose a scale factor (or zoom level) for displaying an image, and your application is able to automatically choose one that will enable the image to fit completely within the display window, you can set up the spin box like this:

 
Sélectionnez
    QSpinBox *zoomSpinBox = new QSpinBox;
    zoomSpinBox-&gt;setRange(0, 1000);
    zoomSpinBox-&gt;setSingleStep(10);
    zoomSpinBox-&gt;setSuffix("%");
    zoomSpinBox-&gt;setSpecialValueText(tr("Automatic"));
    zoomSpinBox-&gt;setValue(100);

The user will then be able to choose a scale from 1% to 1000% or select "Auto" to leave it up to the application to choose. Your code must then interpret the spin box value of 0 as a request from the user to scale the image to fit inside the window.

All values are displayed with the prefix and suffix (if set), except for the special value, which only shows the special value text. This special text is passed in the QSpinBox::textChanged() signal that passes a QString.

To turn off the special-value text display, call this function with an empty string. The default is no special-value text, i.e. the numeric value is shown as usual.

If no special-value text is set, specialValueText() returns an empty string.

Access functions:

  • specialValueText() const

  • void setSpecialValueText(const &txt)

[read-only] text : const QString

This property holds the spin box's text, including any prefix and suffix

There is no default text.

Access functions:

  • text() const

wrapping : bool

This property holds whether the spin box is circular.

If wrapping is true stepping up from maximum() value will take you to the minimum() value and vice versa. Wrapping only make sense if you have minimum() and maximum() values set.

 
Sélectionnez
QSpinBox *spinBox = new QSpinBox(this);
spinBox-&gt;setRange(0, 100);
spinBox-&gt;setWrapping(true);
spinBox-&gt;setValue(100);
spinBox-&gt;stepBy(1);
// value is 0

Access functions:

  • bool wrapping() const

  • void setWrapping(bool w)

See Also

Member Function Documentation

 

[explicit] QAbstractSpinBox::QAbstractSpinBox(QWidget *parent = nullptr)

Constructs an abstract spinbox with the given parent with default wrapping, and alignment properties.

[virtual] QAbstractSpinBox::~QAbstractSpinBox()

Called when the QAbstractSpinBox is destroyed.

[override virtual protected] void QAbstractSpinBox::changeEvent(QEvent *event)

[virtual] void QAbstractSpinBox::clear()

Clears the lineedit of all text but prefix and suffix.

[override virtual protected] void QAbstractSpinBox::closeEvent(QCloseEvent *event)

[override virtual protected] void QAbstractSpinBox::contextMenuEvent(QContextMenuEvent *event)

void QAbstractSpinBox::editingFinished()

This signal is emitted editing is finished. This happens when the spinbox loses focus and when enter is pressed.

[override virtual] bool QAbstractSpinBox::event(QEvent *event)

[virtual] void QAbstractSpinBox::fixup(QString &input) const

This virtual function is called by the QAbstractSpinBox if the input is not validated to QValidator::Acceptable when Return is pressed or interpretText() is called. It will try to change the text so it is valid. Reimplemented in the various subclasses.

[override virtual protected] void QAbstractSpinBox::focusInEvent(QFocusEvent *event)

[override virtual protected] void QAbstractSpinBox::focusOutEvent(QFocusEvent *event)

[override virtual protected] void QAbstractSpinBox::hideEvent(QHideEvent *event)

[virtual protected] void QAbstractSpinBox::initStyleOption(QStyleOptionSpinBox *option) const

Initialize option with the values from this QSpinBox. This method is useful for subclasses when they need a QStyleOptionSpinBox, but don't want to fill in all the information themselves.

See Also

[override virtual] QVariant QAbstractSpinBox::inputMethodQuery(Qt::InputMethodQuery query) const

void QAbstractSpinBox::interpretText()

This function interprets the text of the spin box. If the value has changed since last interpretation it will emit signals.

[override virtual protected] void QAbstractSpinBox::keyPressEvent(QKeyEvent *event)

Reimplements: QWidget::keyPressEvent(QKeyEvent *event).

This function handles keyboard input.

The following keys are handled specifically:

Enter/Return

This will reinterpret the text and emit a signal even if the value has not changed since last time a signal was emitted.

Up

This will invoke stepBy(1)

Down

This will invoke stepBy(-1)

Page up

This will invoke stepBy(10)

Page down

This will invoke stepBy(-10)

See Also

See also stepBy()

[override virtual protected] void QAbstractSpinBox::keyReleaseEvent(QKeyEvent *event)

[protected] QLineEdit *QAbstractSpinBox::lineEdit() const

This function returns a pointer to the line edit of the spin box.

See Also

See also setLineEdit()

[override virtual] QSize QAbstractSpinBox::minimumSizeHint() const

Reimplements an access function for property: QWidget::minimumSizeHint.

[override virtual protected] void QAbstractSpinBox::mouseMoveEvent(QMouseEvent *event)

[override virtual protected] void QAbstractSpinBox::mousePressEvent(QMouseEvent *event)

[override virtual protected] void QAbstractSpinBox::mouseReleaseEvent(QMouseEvent *event)

[override virtual protected] void QAbstractSpinBox::paintEvent(QPaintEvent *event)

[override virtual protected] void QAbstractSpinBox::resizeEvent(QResizeEvent *event)

void QAbstractSpinBox::selectAll()

Selects all the text in the spinbox except the prefix and suffix.

[protected] void QAbstractSpinBox::setLineEdit(QLineEdit *lineEdit)

Sets the line edit of the spinbox to be lineEdit instead of the current line edit widget. lineEdit cannot be nullptr.

QAbstractSpinBox takes ownership of the new lineEdit

If QLineEdit::validator() for the lineEdit returns nullptr, the internal validator of the spinbox will be set on the line edit.

See Also

See also lineEdit()

[override virtual protected] void QAbstractSpinBox::showEvent(QShowEvent *event)

[override virtual] QSize QAbstractSpinBox::sizeHint() const

Reimplements an access function for property: QWidget::sizeHint.

[virtual] void QAbstractSpinBox::stepBy(int steps)

Virtual function that is called whenever the user triggers a step. The steps parameter indicates how many steps were taken. For example, pressing Qt::Key_Down will trigger a call to stepBy(-1), whereas pressing Qt::Key_PageUp will trigger a call to stepBy(10).

If you subclass QAbstractSpinBox you must reimplement this function. Note that this function is called even if the resulting value will be outside the bounds of minimum and maximum. It's this function's job to handle these situations.

See Also

See also stepUp(), stepDown(), keyPressEvent()

void QAbstractSpinBox::stepDown()

Steps down by one linestep Calling this slot is analogous to calling stepBy(-1);

See Also

See also stepBy(), stepUp()

[virtual protected] QAbstractSpinBox::StepEnabled QAbstractSpinBox::stepEnabled() const

Virtual function that determines whether stepping up and down is legal at any given time.

The up arrow will be painted as disabled unless (stepEnabled() & StepUpEnabled) != 0.

The default implementation will return (StepUpEnabled| StepDownEnabled) if wrapping is turned on. Else it will return StepDownEnabled if value is > minimum() or'ed with StepUpEnabled if value < maximum().

If you subclass QAbstractSpinBox you will need to reimplement this function.

See Also

void QAbstractSpinBox::stepUp()

Steps up by one linestep Calling this slot is analogous to calling stepBy(1);

See Also

See also stepBy(), stepDown()

[override virtual protected] void QAbstractSpinBox::timerEvent(QTimerEvent *event)

[virtual] QValidator::State QAbstractSpinBox::validate(QString &input, int &pos) const

This virtual function is called by the QAbstractSpinBox to determine whether input is valid. The pos parameter indicates the position in the string. Reimplemented in the various subclasses.

[override virtual protected] void QAbstractSpinBox::wheelEvent(QWheelEvent *event)

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