get_child_at interface

This page explains the container class, like the Graphics, Sprite, Stage) get_child_at method interface.

What interface is this?

The get_child_at interface returns a child (DisplayObject) instance at the specified index.

Basic usage

The following code example is adding the rectangle to the sprite container. The Sprite class adds the Graphics instance at the constructor so that the first child becomes the Graphics instance. The second child becomes the Rectangle instance, which the sprite added with the add_child method.

import apysc as ap

ap.Stage(
    background_color=ap.Color("#333"),
    stage_width=450,
    stage_height=150,
    stage_elem_id="stage",
)

sprite: ap.Sprite = ap.Sprite()
sprite.graphics.begin_fill(color=ap.Color("#0af"))
rectangle_1: ap.Rectangle = sprite.graphics.draw_rect(x=50, y=50, width=50, height=50)
sprite.add_child(rectangle_1)

first_child: ap.DisplayObject = sprite.get_child_at(index=0)
assert isinstance(first_child, ap.Graphics)

second_child: ap.DisplayObject = sprite.get_child_at(index=1)
assert isinstance(second_child, ap.Rectangle)

get_child_at API

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[Interface signature] get_child_at(self, index: Union[int, apysc._type.int.Int]) -> apysc._display.display_object.DisplayObject

[Interface summary]

Get a child at a specified index.

[Parameters]

  • index: int or Int

    • Child’s index (start from 0).

[Returns]

  • child: DisplayObject

    • Target index child instance.

[Examples]

>>> import apysc as ap
>>> stage: ap.Stage = ap.Stage()
>>> sprite: ap.Sprite = ap.Sprite()
>>> sprite.graphics.begin_fill(color=ap.Color("#0af"), alpha=0.5)
>>> rectangle_1: ap.Rectangle = sprite.graphics.draw_rect(
...     x=50, y=50, width=50, height=50
... )
>>> rectangle_2: ap.Rectangle = sprite.graphics.draw_rect(
...     x=150, y=50, width=50, height=50
... )
>>> child_at_index_1: ap.DisplayObject = sprite.graphics.get_child_at(1)
>>> child_at_index_1 == rectangle_2
True