Class Scroller

Definition

Namespace:

ElmSharp

Assembly:

ElmSharp.dll

The Scroller is a container that holds and clips a single object and allows you to scroll across it.

public class Scroller : Layout, IAccessibleObject

Inheritance

object

EvasObject

AccessibleObject

Widget

Container

Layout

Scroller

Derived

CircleScroller

CircleScroller

CircleScroller

CircleScroller

CircleScroller

CircleScroller

CircleScroller

CircleScroller

CircleScroller

Implements

IAccessibleObject

Constructors

Scroller()

Creates and initializes a new instance of the Scroller class.

Declaration

public Scroller()

Scroller(EvasObject)

Creates and initializes a new instance of the Scroller class.

Declaration

public Scroller(EvasObject parent)

Parameters

Type	Name	Description
EvasObject	parent	The EvasObject to which the new Scroller will be attached as a child.

Properties

ChildHeight

Gets the height of the content object of the scroller.

Declaration

public int ChildHeight { get; }

Property Value

Type	Description
int

ChildWidth

Gets the width of the content object of the scroller.

Declaration

public int ChildWidth { get; }

Property Value

Type	Description
int

ContentPropagateEvents

Gets or sets the event propagation for a scroller. This enables or disables event propagation from the scroller content to the scroller and its parent. By default, event propagation is enabled.

Declaration

public bool ContentPropagateEvents { get; set; }

Property Value

Type	Description
bool

CurrentRegion

Gets the current region in the content object that is visible through the scroller.

Declaration

public Rect CurrentRegion { get; }

Property Value

Type	Description
Rect

HorizontalBounce

Sets or gets the horizontal bounce behaviour. When scrolling, the scroller may "bounce" when reaching an edge of the content object. This is a visual way to indicate the end has been reached. This is enabled by default for both axis. This API will set if it is enabled for the given axis with the boolean parameters for each axis.

Declaration

public bool HorizontalBounce { get; set; }

Property Value

Type	Description
bool

HorizontalGravity

Sets the scrolling gravity values for a scroller. The gravity defines how the scroller will adjust its view when the size of the scroller contents increase. The scroller will adjust the view to glue itself as follows: x=0.0, for staying where it is relative to the left edge of the content, x=1.0, for staying where it is relative to the rigth edge of the content, y=0.0, for staying where it is relative to the top edge of the content, y=1.0, for staying where it is relative to the bottom edge of the content. Default values for x and y are 0.0.

Declaration

public double HorizontalGravity { get; set; }

Property Value

Type	Description
double

HorizontalLoop

Sets an infinite loop_ for a scroller. This function sets the infinite loop horizontally. If the content is set, it will be shown repeatedly.

Declaration

public bool HorizontalLoop { get; set; }

Property Value

Type	Description
bool

HorizontalPageIndex

Sets or gets the scroll current page number.

Declaration

public int HorizontalPageIndex { get; }

Property Value

Type	Description
int

Remarks

Current page means the page which meets the left of the viewport. If there are two or more pages in the viewport, it returns the number of the page which meets the left of the viewport. The page number starts from 0. 0 is the first page.

HorizontalPageScrollLimit

Sets or gets the maximum limit of the movable page at horizontal direction.

Declaration

public int HorizontalPageScrollLimit { get; set; }

Property Value

Type	Description
int

HorizontalRelativePageSize

Gets or sets a given scroller widget's scrolling page size, relative to its viewport size.

Declaration

public double HorizontalRelativePageSize { get; set; }

Property Value

Type	Description
double

HorizontalScrollBarVisiblePolicy

Sets or gets the value of HorizontalScrollBarVisiblePolicy.

Declaration

public virtual ScrollBarVisiblePolicy HorizontalScrollBarVisiblePolicy { get; set; }

Property Value

Type	Description
ScrollBarVisiblePolicy

Remarks

ScrollBarVisiblePolicy.Auto means the horizontal scrollbar is made visible if it is needed, and otherwise kept hidden. ScrollBarVisiblePolicy.Visible turns it on all the time, and ScrollBarVisiblePolicy.Invisible always keeps it off.

HorizontalSnap

Gets or sets the page snapping behavior of a scroller.

Declaration

public bool HorizontalSnap { get; set; }

Property Value

Type	Description
bool

Remarks

When scrolling, if a scroller is paged (see HorizontalRelativePageSize), the scroller may snap to pages when being scrolled, i.e., even if it had momentum to scroll further, it will stop at the next page boundaries. This is disabled, by default, for both axis. This function will set if it that is enabled or not, for each axis.

HorizontalStepSize

Gets or sets the step size to move scroller by key event.

Declaration

public int HorizontalStepSize { get; set; }

Property Value

Type	Description
int

LastHorizontalPageNumber

Gets the scroll last page number. The page number starts from 0. 0 is the first page. This returns the last page number among the pages.

Declaration

public int LastHorizontalPageNumber { get; }

Property Value

Type	Description
int

LastVerticalPageNumber

Gets the scroll last page number. The page number starts from 0. 0 is the first page. This returns the last page number among the pages.

Declaration

public int LastVerticalPageNumber { get; }

Property Value

Type	Description
int

PageHeight

Gets or sets the page size to an absolute fixed value, with 0 turning it off for that axis.

Declaration

public int PageHeight { get; set; }

Property Value

Type	Description
int

PageWidth

Gets or sets the page size to an absolute fixed value, with 0 turning it off for that axis.

Declaration

public int PageWidth { get; set; }

Property Value

Type	Description
int

ScrollBlock

Sets or gets the value of ScrollBlock.

Declaration

public ScrollBlock ScrollBlock { get; set; }

Property Value

Type	Description
ScrollBlock

Remarks

This function will block scrolling movement in a given direction. One can disable movements in the X-axis, the Y-axis, or both. The default value is ScrollBlock.None, where movements are allowed in both directions.

SingleDirection

Gets or sets the type of single direction scroll.

Declaration

public ScrollSingleDirection SingleDirection { get; set; }

Property Value

Type	Description
ScrollSingleDirection

VerticalBounce

Sets or gets the vertical bounce behaviour. When scrolling, the scroller may "bounce" when reaching an edge of the content object. This is a visual way to indicate the end has been reached. This is enabled by default for both axis. This API will set if it is enabled for the given axis with the boolean parameters for each axis.

Declaration

public bool VerticalBounce { get; set; }

Property Value

Type	Description
bool

VerticalGravity

Sets the scrolling gravity values for a scroller. The gravity defines how the scroller will adjust its view when the size of the scroller contents increase. The scroller will adjust the view to glue itself as follows: x=0.0, for staying where it is relative to the left edge of the content, x=1.0, for staying where it is relative to the rigth edge of the content, y=0.0, for staying where it is relative to the top edge of the content, y=1.0, for staying where it is relative to the bottom edge of the content. Default values for x and y are 0.0.

Declaration

public double VerticalGravity { get; set; }

Property Value

Type	Description
double

VerticalLoop

Sets an infinite loop_ for a scroller. This function sets the infinite loop vertically. If the content is set, it will be shown repeatedly.

Declaration

public bool VerticalLoop { get; set; }

Property Value

Type	Description
bool

VerticalPageIndex

Sets or gets the scroll current page number.

Declaration

public int VerticalPageIndex { get; }

Property Value

Type	Description
int

Remarks

Current page means the page which meets the top of the viewport. If there are two or more pages in the viewport, it returns the number of the page which meets the top of the viewport. The page number starts from 0. 0 is the first page.

VerticalPageScrollLimit

Sets or gets the maximum limit of the movable page at vertical direction.

Declaration

public int VerticalPageScrollLimit { get; set; }

Property Value

Type	Description
int

VerticalRelativePageSize

Gets or sets a given scroller widget's scrolling page size, relative to its viewport size.

Declaration

public double VerticalRelativePageSize { get; set; }

Property Value

Type	Description
double

VerticalScrollBarVisiblePolicy

Sets or gets the value of VerticalScrollBarVisiblePolicy.

Declaration

public virtual ScrollBarVisiblePolicy VerticalScrollBarVisiblePolicy { get; set; }

Property Value

Type	Description
ScrollBarVisiblePolicy

Remarks

ScrollBarVisiblePolicy.Auto means the vertical scrollbar is made visible if it is needed, and otherwise kept hidden. ScrollBarVisiblePolicy.Visible turns it on all the time, and ScrollBarVisiblePolicy.Invisible always keeps it off.

VerticalSnap

Gets or sets the page snapping behavior of a scroller.

Declaration

public bool VerticalSnap { get; set; }

Property Value

Type	Description
bool

Remarks

When scrolling, if a scroller is paged (see VerticalRelativePageSize), the scroller may snap to pages when being scrolled, i.e., even if it had momentum to scroll further, it will stop at the next page boundaries. This is disabled, by default, for both axis. This function will set if it that is enabled or not, for each axis.

VerticalStepSize

Gets or sets the step size to move scroller by key event.

Declaration

public int VerticalStepSize { get; set; }

Property Value

Type	Description
int

WheelDisabled

Gets or sets a value whether mouse wheel is enabled or not over the scroller.

Declaration

public bool WheelDisabled { get; set; }

Property Value

Type	Description
bool

Methods

CreateHandle(EvasObject)

Creates a widget handle.

Declaration

protected override IntPtr CreateHandle(EvasObject parent)

Parameters

Type	Name	Description
EvasObject	parent	Parent EvasObject.

Returns

Type	Description
System.IntPtr	Handle IntPtr.

Overrides

Layout.CreateHandle(EvasObject)

MinimumLimit(bool, bool)

Sets the scroller minimum size limited to the minimum size of the content. By default, the scroller will be as small as its design allows, irrespective of its content. This will make the scroller minimum size the right size horizontally and/or vertically to perfectly fit its content in that direction.

Declaration

public void MinimumLimit(bool horizontal, bool vertical)

Parameters

Type	Name	Description
bool	horizontal	Enable limiting minimum size horizontally.
bool	vertical	Enable limiting minimum size vertically.

OnRealized()

The callback of the Realized event.

Declaration

protected override void OnRealized()

Overrides

Layout.OnRealized()

ScrollTo(Rect, bool)

Shows a specific virtual region within the scroller content object.

Declaration

public void ScrollTo(Rect region, bool animated)

Parameters

Type	Name	Description
Rect	region	Rect struct of region.
bool	animated	True means allows the scroller to "smoothly slide" to this location.

Remarks

This ensures that all (or part, if it does not fit) of the designated region in the virtual content object ((0, 0) starting at the top-left of the virtual content object) is shown within the scroller. If set "animated" to true, it will allows the scroller to "smoothly slide" to this location (if configuration in general calls for transitions). It may not jump immediately to the new location and may take a while and show other content along the way.

ScrollTo(int, int, bool)

Shows a specific virtual region within the scroller content object by the page number. (0, 0) of the indicated page is located at the top-left corner of the viewport.

Declaration

public void ScrollTo(int horizontalPageIndex, int verticalPageIndex, bool animated)

Parameters

Type	Name	Description
int	horizontalPageIndex	The horizontal page number.
int	verticalPageIndex	The vertical page number.
bool	animated	True means slider with animation.

SetPageSize(double, double)

Sets the scroll page size relative to the viewport size.

Declaration

public void SetPageSize(double width, double height)

Parameters

Type	Name	Description
double	width	The horizontal page relative size.
double	height	The vertical page relative size.

Remarks

The scroller is capable of limiting scrolling by the user to "pages". That is to jump by and only show a "whole page" at a time as if the continuous area of the scroller content is split into page sized pieces. This sets the size of a page relative to the viewport of the scroller. 1.0 is "1 viewport" which is the size (horizontally or vertically). 0.0 turns it off in that axis. This is mutually exclusive with the page size (see elm_scroller_page_size_set() for more information). Likewise 0.5 is "half a viewport". Usable values are normally between 0.0 and 1.0 including 1.0. If you only want 1 axis to be page "limited", use 0.0 for the other axis.

SetPageSize(int, int)

Sets the page size to an absolute fixed value, with 0 turning it off for that axis.

Declaration

public void SetPageSize(int width, int height)

Parameters

Type	Name	Description
int	width	The horizontal page size.
int	height	The vertical page size.

Events

DragStart

DragStart will be triggered when dragging the contents around has started.

Declaration

public event EventHandler DragStart

Event Type

Type	Description
System.EventHandler

DragStop

DragStop will be triggered when dragging the contents around has stopped.

Declaration

public event EventHandler DragStop

Event Type

Type	Description
System.EventHandler

PageScrolled

PageScrolled will be triggered when the visible page has changed.

Declaration

public event EventHandler PageScrolled

Event Type

Type	Description
System.EventHandler

Scrolled

Scrolled will be triggered when the content has been scrolled.

Declaration

public event EventHandler Scrolled

Event Type

Type	Description
System.EventHandler

Implements

IAccessibleObject

Extension Methods

RotaryEventExtensions.Activate(EvasObject)

RotaryEventExtensions.AddRotaryEventHandler(EvasObject, RotaryEventHandler)

RotaryEventExtensions.Deactivate(EvasObject)

RotaryEventExtensions.RemoveRotaryEventHandler(EvasObject, RotaryEventHandler)