QSizePolicy Class

成员函数

QSizePolicy::QSizePolicy()

Constructs a QSizePolicy object with Fixed as its horizontal and vertical policies.

The policies can be altered using the setHorizontalPolicy() and setVerticalPolicy() functions. Use the setHeightForWidth() function if the preferred height of the widget is dependent on the width of the widget (for example, a QLabel with line wrapping).

参见 setHorizontalStretch() and setVerticalStretch().

QSizePolicy::QSizePolicy(Policy horizontal, Policy vertical, ControlType type = DefaultType)

Constructs a QSizePolicy object with the given horizontal and vertical policies, and the specified control type.

Use setHeightForWidth() if the preferred height of the widget is dependent on the width of the widget (for example, a QLabel with line wrapping).

This function was introduced in Qt 4.3.

参见 setHorizontalStretch(), setVerticalStretch(), and controlType().

ControlType QSizePolicy::controlType() const

Returns the control type associated with the widget for which this size policy applies.

This function was introduced in Qt 4.3.

参见 setControlType().

Qt::Orientations QSizePolicy::expandingDirections() const

Returns whether a widget can make use of more space than the QWidget::sizeHint() function indicates.

A value of Qt::Horizontal or Qt::Vertical means that the widget can grow horizontally or vertically (i.e., the horizontal or vertical policy is Expanding or MinimumExpanding), whereas Qt::Horizontal | Qt::Vertical means that it can grow in both dimensions.

参见 horizontalPolicy() and verticalPolicy().

bool QSizePolicy::hasHeightForWidth() const

Returns true if the widget's preferred height depends on its width; otherwise returns false.

参见 setHeightForWidth().

bool QSizePolicy::hasWidthForHeight() const

Returns true if the widget's width depends on its height; otherwise returns false.

参见 setWidthForHeight().

Policy QSizePolicy::horizontalPolicy() const

Returns the horizontal component of the size policy.

参见 setHorizontalPolicy(), verticalPolicy(), and horizontalStretch().

int QSizePolicy::horizontalStretch() const

Returns the horizontal stretch factor of the size policy.

参见 setHorizontalStretch(), verticalStretch(), and horizontalPolicy().

bool QSizePolicy::retainSizeWhenHidden() const

Returns whether the layout should retain the widget's size when it is hidden. This is false by default.

This function was introduced in Qt 5.2.

参见 setRetainSizeWhenHidden().

void QSizePolicy::setControlType(ControlType type)

Sets the control type associated with the widget for which this size policy applies to type.

The control type specifies the type of the widget for which this size policy applies. It is used by some styles, notably QMacStyle, to insert proper spacing between widgets. For example, the macOS Aqua guidelines specify that push buttons should be separated by 12 pixels, whereas vertically stacked radio buttons only require 6 pixels.

This function was introduced in Qt 4.3.

参见 controlType() and QStyle::layoutSpacing().

void QSizePolicy::setHeightForWidth(bool dependent)

Sets the flag determining whether the widget's preferred height depends on its width, to dependent.

参见 hasHeightForWidth() and setWidthForHeight().

void QSizePolicy::setHorizontalPolicy(Policy policy)

Sets the horizontal component to the given policy.

参见 horizontalPolicy(), setVerticalPolicy(), and setHorizontalStretch().

void QSizePolicy::setHorizontalStretch(int stretchFactor)

Sets the horizontal stretch factor of the size policy to the given stretchFactor. stretchFactor must be in the range [0,255].

When two widgets are adjacent to each other in a horizontal layout, setting the horizontal stretch factor of the widget on the left to 2 and the factor of widget on the right to 1 will ensure that the widget on the left will always be twice the size of the one on the right.

参见 horizontalStretch(), setVerticalStretch(), and setHorizontalPolicy().

void QSizePolicy::setRetainSizeWhenHidden(bool retainSize)

Sets whether a layout should retain the widget's size when it is hidden. If retainSize is true, the layout will not be changed by hiding the widget.

This function was introduced in Qt 5.2.

参见 retainSizeWhenHidden().

void QSizePolicy::setVerticalPolicy(Policy policy)

Sets the vertical component to the given policy.

参见 verticalPolicy(), setHorizontalPolicy(), and setVerticalStretch().

void QSizePolicy::setVerticalStretch(int stretchFactor)

Sets the vertical stretch factor of the size policy to the given stretchFactor. stretchFactor must be in the range [0,255].

When two widgets are adjacent to each other in a vertical layout, setting the vertical stretch factor of the widget on the top to 2 and the factor of widget on the bottom to 1 will ensure that the widget on the top will always be twice the size of the one on the bottom.

参见 verticalStretch(), setHorizontalStretch(), and setVerticalPolicy().

void QSizePolicy::setWidthForHeight(bool dependent)

Sets the flag determining whether the widget's width depends on its height, to dependent.

This is only supported for QGraphicsLayout's subclasses. It is not possible to have a layout with both height-for-width and width-for-height constraints at the same time.

参见 hasWidthForHeight() and setHeightForWidth().

void QSizePolicy::transpose()

Swaps the horizontal and vertical policies and stretches.

参见 transposed().

QSizePolicy QSizePolicy::transposed() const

Returns a size policy object with the horizontal and vertical policies and stretches swapped.

This function was introduced in Qt 5.9.

参见 transpose().

Policy QSizePolicy::verticalPolicy() const

Returns the vertical component of the size policy.

参见 setVerticalPolicy(), horizontalPolicy(), and verticalStretch().

int QSizePolicy::verticalStretch() const

Returns the vertical stretch factor of the size policy.

参见 setVerticalStretch(), horizontalStretch(), and verticalPolicy().

QSizePolicy::operator QVariant() const

Returns a QVariant storing this QSizePolicy.

bool QSizePolicy::operator!=(const QSizePolicy &other) const

Returns true if this policy is different from other; otherwise returns false.

参见 operator==().

bool QSizePolicy::operator==(const QSizePolicy &other) const

Returns true if this policy is equal to other; otherwise returns false.

参见 operator!=().