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QScrollBar

QScrollArea

QScrollArea class provides a scrolling view onto another widget. 更多 …

Inheritance diagram of PySide2.QtWidgets.QScrollArea

概要

函数

详细描述

A scroll area is used to display the contents of a child widget within a frame. If the widget exceeds the size of the frame, the view can provide scroll bars so that the entire area of the child widget can be viewed. The child widget must be specified with setWidget() 。例如： 

imageLabel = QLabel()
image = QImage("happyguy.png")
imageLabel.setPixmap(QPixmap.fromImage(image))
scrollArea = QScrollArea()
scrollArea.setBackgroundRole(QPalette.Dark)
scrollArea.setWidget(imageLabel)

The code above creates a scroll area (shown in the images below) containing an image label. When scaling the image, the scroll area can provide the necessary scroll bars:

qscrollarea-noscrollbars1

qscrollarea-onescrollbar2

qscrollarea-twoscrollbars3

The scroll bars appearance depends on the currently set scroll bar policies . You can control the appearance of the scroll bars using the inherited functionality from QAbstractScrollArea .

For example, you can set the horizontalScrollBarPolicy and verticalScrollBarPolicy properties. Or if you want the scroll bars to adjust dynamically when the contents of the scroll area changes, you can use the horizontalScrollBar() and verticalScrollBar() functions (which enable you to access the scroll bars) and set the scroll bars’ values whenever the scroll area’s contents change, using the setValue() 函数。

You can retrieve the child widget using the widget() function. The view can be made to be resizable with the setWidgetResizable() function. The alignment of the widget can be specified with setAlignment() .

Two convenience functions ensureVisible() and ensureWidgetVisible() ensure a certain region of the contents is visible inside the viewport, by scrolling the contents if necessary.

Size Hints and Layouts

When using a scroll area to display the contents of a custom widget, it is important to ensure that the size hint of the child widget is set to a suitable value. If a standard QWidget is used for the child widget, it may be necessary to call setMinimumSize() to ensure that the contents of the widget are shown correctly within the scroll area.

If a scroll area is used to display the contents of a widget that contains child widgets arranged in a layout, it is important to realize that the size policy of the layout will also determine the size of the widget. This is especially useful to know if you intend to dynamically change the contents of the layout. In such cases, setting the layout’s size constraint property to one which provides constraints on the minimum and/or maximum size of the layout (e.g., SetMinAndMaxSize ) will cause the size of the scroll area to be updated whenever the contents of the layout changes.

For a complete example using the QScrollArea class, see the Image Viewer example. The example shows how to combine QLabel and QScrollArea 以显示图像。

另请参阅

QAbstractScrollArea QScrollBar 图像查看器范例

class QScrollArea ( [ parent=None ] )
param parent

QWidget

Constructs an empty scroll area with the given parent .

另请参阅

setWidget()

PySide2.QtWidgets.QScrollArea. alignment ( )
返回类型

Alignment

另请参阅

setAlignment()

PySide2.QtWidgets.QScrollArea. ensureVisible ( x , y [ , xmargin=50 [ , ymargin=50 ] ] )
参数

  • x – int

  • y – int

  • xmargin – int

  • ymargin – int

Scrolls the contents of the scroll area so that the point ( x , y ) is visible inside the region of the viewport with margins specified in pixels by xmargin and ymargin . If the specified point cannot be reached, the contents are scrolled to the nearest valid position. The default value for both margins is 50 pixels.

PySide2.QtWidgets.QScrollArea. ensureWidgetVisible ( childWidget [ , xmargin=50 [ , ymargin=50 ] ] )
参数

  • childWidget – QWidget

  • xmargin – int

  • ymargin – int

Scrolls the contents of the scroll area so that the childWidget of widget() is visible inside the viewport with margins specified in pixels by xmargin and ymargin . If the specified point cannot be reached, the contents are scrolled to the nearest valid position. The default value for both margins is 50 pixels.

PySide2.QtWidgets.QScrollArea. setAlignment ( arg__1 )
参数

arg__1 – Alignment

另请参阅

alignment()

PySide2.QtWidgets.QScrollArea. setWidget ( widget )
参数

widget – QWidget

Sets the scroll area’s widget .

widget becomes a child of the scroll area, and will be destroyed when the scroll area is deleted or when a new widget is set.

The widget’s autoFillBackground property will be set to true .

If the scroll area is visible when the widget is added, you must show() it explicitly.

Note that You must add the layout of widget before you call this function; if you add it later, the widget will not be visible - regardless of when you show() the scroll area. In this case, you can also not show() the widget later.

另请参阅

widget()

PySide2.QtWidgets.QScrollArea. setWidgetResizable ( resizable )
参数

resizable – bool

另请参阅

widgetResizable()

PySide2.QtWidgets.QScrollArea. takeWidget ( )
返回类型

QWidget

Removes the scroll area’s widget, and passes ownership of the widget to the caller.

另请参阅

widget()

PySide2.QtWidgets.QScrollArea. widget ( )
返回类型

QWidget

Returns the scroll area’s widget, or None 若没有。

另请参阅

setWidget()

PySide2.QtWidgets.QScrollArea. widgetResizable ( )
返回类型

bool

另请参阅

setWidgetResizable()