程序包 ohos.agp.components

接口 Component.DrawTask

封闭类:

Component

public static interface Component.DrawTask

Implements a draw task.

You can use Component.addDrawTask(ohos.agp.components.Component.DrawTask) and Component.addDrawTask(ohos.agp.components.Component.DrawTask,int) to add a draw task in a control, and invoke the callback when the control is updated by Component.invalidate().

字段概要

字段

限定符和类型	字段	说明
static int	BETWEEN_BACKGROUND_AND_CONTENT	Indicates that the draw task is implemented between the content and background of a control.
static int	BETWEEN_CONTENT_AND_FOREGROUND	Indicates that the draw task is implemented between the content and foreground of a control.

方法概要

限定符和类型	方法	说明
void	onDraw(Component component, Canvas canvas)	Called when a component is updated through a draw task.

字段详细资料

BETWEEN_BACKGROUND_AND_CONTENT

static final int BETWEEN_BACKGROUND_AND_CONTENT

Indicates that the draw task is implemented between the content and background of a control.

另请参阅:

常量字段值

BETWEEN_CONTENT_AND_FOREGROUND

static final int BETWEEN_CONTENT_AND_FOREGROUND

Indicates that the draw task is implemented between the content and foreground of a control.

另请参阅:

常量字段值

方法详细资料

onDraw

void onDraw(Component component,
            Canvas canvas)

Called when a component is updated through a draw task.

The draw task uses the attributes of the parent canvas for drawing an object, such as alpha, width, and height.

参数:

component - Indicates the parent canvas.

canvas - Indicates the canvas used for drawing in this draw task.

另请参阅:

Component.addDrawTask(DrawTask), Component.addDrawTask(DrawTask, int), Component.invalidate()