主题
CandlestickChart 继承自: ft.LayoutControl, Control, BaseControl
Draws a candlestick chart representing OHLC values.
python
fch.CandlestickChart(
min_x=-1,
max_x=2,
min_y=20,
max_y=30,
bgcolor=ft.Colors.AMBER_200,
spots=[
fch.CandlestickChartSpot(
x=0,
open=22.6,
high=28.3,
low=21.4,
close=24.1,
),
...,
],
)示例
python
import flet as ft
import flet_charts as fch
CANDLE_DATA = [
("Mon", 24.8, 28.6, 23.9, 27.2),
("Tue", 27.2, 30.1, 25.8, 28.4),
("Wed", 28.4, 31.2, 26.5, 29.1),
("Thu", 29.1, 32.4, 27.9, 31.8),
("Fri", 31.8, 34.0, 29.7, 30.2),
("Sat", 30.2, 33.6, 28.3, 32.7),
("Sun", 32.7, 35.5, 30.1, 34.6),
]
def build_spots() -> list[fch.CandlestickChartSpot]:
"""Create candlestick spots from the static data."""
spots: list[fch.CandlestickChartSpot] = []
for index, (label, open_, high, low, close) in enumerate(CANDLE_DATA):
spots.append(
fch.CandlestickChartSpot(
x=float(index),
open=open_,
high=high,
low=low,
close=close,
selected=index == len(CANDLE_DATA) - 1,
tooltip=fch.CandlestickChartSpotTooltip(
text=(
f"{label}\n"
f"Open: {open_:0.1f}\n"
f"High: {high:0.1f}\n"
f"Low : {low:0.1f}\n"
f"Close: {close:0.1f}"
),
bottom_margin=12,
),
)
)
return spots
def main(page: ft.Page):
page.title = "Candlestick chart"
page.padding = 24
page.theme_mode = ft.ThemeMode.DARK
info = ft.Text("Interact with the chart to see event details.")
spots = build_spots()
min_x = -0.5
max_x = len(spots) - 0.5
min_y = min(low for _, _, _, low, _ in CANDLE_DATA) - 1
max_y = max(high for _, _, _, _, high in CANDLE_DATA) + 1
def handle_event(e: fch.CandlestickChartEvent):
if e.spot_index is not None and e.spot_index >= 0:
label, open_, high, low, close = CANDLE_DATA[e.spot_index]
info.value = (
f"{e.type.value} • {label}: "
f"O {open_:0.1f} H {high:0.1f} L {low:0.1f} C {close:0.1f}"
)
else:
info.value = f"{e.type.value} • outside candlesticks"
info.update()
chart = fch.CandlestickChart(
expand=True,
min_x=min_x,
max_x=max_x,
min_y=min_y,
max_y=max_y,
baseline_x=0,
baseline_y=min_y,
bgcolor=ft.Colors.with_opacity(0.2, ft.Colors.BLUE_GREY_900),
horizontal_grid_lines=fch.ChartGridLines(interval=2, dash_pattern=[2, 2]),
vertical_grid_lines=fch.ChartGridLines(interval=1, dash_pattern=[2, 2]),
left_axis=fch.ChartAxis(
label_spacing=2,
label_size=60,
title=ft.Text("Price (k USD)", color=ft.Colors.GREY_300),
show_min=False,
),
bottom_axis=fch.ChartAxis(
labels=[
fch.ChartAxisLabel(
value=index,
label=ft.Text(name, color=ft.Colors.GREY_300),
)
for index, (name, *_rest) in enumerate(CANDLE_DATA)
],
label_spacing=1,
label_size=40,
show_min=False,
show_max=False,
),
spots=spots,
tooltip=fch.CandlestickChartTooltip(
bgcolor=ft.Colors.BLUE_GREY_800,
horizontal_alignment=fch.HorizontalAlignment.CENTER,
fit_inside_horizontally=True,
),
on_event=handle_event,
)
page.add(
ft.SafeArea(
expand=True,
content=ft.Container(
expand=True,
border_radius=16,
padding=20,
content=ft.Column(
expand=True,
spacing=20,
controls=[
ft.Text(
"Weekly OHLC snapshot (demo data)",
size=20,
weight=ft.FontWeight.BOLD,
),
chart,
info,
],
),
),
)
)
if __name__ == "__main__":
ft.run(main)
属性
| 名称 | 类型 | 默认值 | 说明 |
|---|---|---|---|
spots | list[CandlestickChartSpot] | [] | Candlesticks to display on the chart. |
animation | ft.AnimationValue | ft.Animation(duration=ft.Duration(milliseconds=150)() | Controls chart implicit animations. |
interactive | bool | True | Enables automatic tooltips and highlighting when hovering the chart. |
show_tooltips_for_selected_spots_only | bool | False | Whether to permanently and only show the tooltips of spots with their selected property set to True. |
long_press_duration | Optional[ft.DurationValue] | None | The duration of a long press on the chart. |
touch_spot_threshold | ft.Number | 4 | The distance threshold to consider a touch near a candlestick. |
bgcolor | Optional[ft.ColorValue] | None | Background color of the chart. |
border | Optional[ft.Border] | None | Border drawn around the chart. |
horizontal_grid_lines | Optional[ChartGridLines] | None | Horizontal grid lines configuration. |
vertical_grid_lines | Optional[ChartGridLines] | None | Vertical grid lines configuration. |
left_axis | Optional[ChartAxis] | None | Appearance of the left axis, its title and labels. |
top_axis | Optional[ChartAxis] | None | Appearance of the top axis, its title and labels. |
right_axis | Optional[ChartAxis] | None | Appearance of the right axis, its title and labels. |
bottom_axis | Optional[ChartAxis] | None | Appearance of the bottom axis, its title and labels. |
baseline_x | Optional[ft.Number] | None | Baseline value on the X axis. |
min_x | Optional[ft.Number] | None | Minimum value displayed on the X axis. |
max_x | Optional[ft.Number] | None | Maximum value displayed on the X axis. |
baseline_y | Optional[ft.Number] | None | Baseline value on the Y axis. |
min_y | Optional[ft.Number] | None | Minimum value displayed on the Y axis. |
max_y | Optional[ft.Number] | None | Maximum value displayed on the Y axis. |
rotation_quarter_turns | ft.Number | 0 | Number of quarter turns (90-degree increments) to rotate the chart. |
tooltip | Optional[CandlestickChartTooltip] | CandlestickChartTooltip(() | Tooltip configuration for the chart. |
width | Optional[Number] | None | Imposed Control width in virtual pixels. |
height | Optional[Number] | None | Imposed Control height in virtual pixels. |
left | Optional[Number] | None | The distance that the child's left edge is inset from the left of the stack. Note: Effective only if this control is a descendant of one of the following: Stack control, overlay list. |
top | Optional[Number] | None | The distance that the child's top edge is inset from the top of the stack. Note: Effective only if this control is a descendant of one of the following: Stack control, overlay list. |
right | Optional[Number] | None | The distance that the child's right edge is inset from the right of the stack. Note: Effective only if this control is a descendant of one of the following: Stack control, overlay list. |
bottom | Optional[Number] | None | The distance that the child's bottom edge is inset from the bottom of the stack. Note: Effective only if this control is a descendant of one of the following: Stack control, overlay list. |
align | Optional[Alignment] | None | Alignment of the control within its parent. |
margin | Optional[MarginValue] | None | Sets the margin of the control. |
rotate | Optional[RotateValue] | None | Transforms this control using a rotation around its center. The value of rotate property could be one of the following types: * number - a rotation in clockwise radians. Full circle 360° is math.pi * 2 radians, 90° is pi / 2, 45° is pi / 4, etc. * Rotate - allows to specify rotation angle as well as alignment - the location of rotation center. Example: python ft.Image( src="https://picsum.photos/100/100", width=100, height=100, border_radius=5, rotate=Rotate(angle=0.25 * pi, alignment=ft.Alignment.CENTER_LEFT) ) |
scale | Optional[ScaleValue] | None | Scales this control along the 2D plane. Default scale factor is 1.0, meaning no-scale. Setting this property to 0.5, for example, makes this control twice smaller, while 2.0 makes it twice larger. Different scale multipliers can be specified for x and y axis, by setting Control.scale property to an instance of Scale class. Either scale or scale_x and scale_y could be specified, but not all of them. Example: python ft.Image( src="https://picsum.photos/100/100", width=100, height=100, border_radius=5, scale=ft.Scale(scale_x=2, scale_y=0.5) ) |
offset | Optional[OffsetValue] | None | Applies a translation transformation before painting the control. The translation is expressed as an Offset scaled to the control's size. So, Offset(x=0.25, y=0), for example, will result in a horizontal translation of one quarter the width of this control. Example The following example displays container at 0, 0 top left corner of a stack as transform applies -1 * 100, -1 * 100 (offset * control's size) horizontal and vertical translations to the control: python import flet as ft def main(page: ft.Page): page.add( ft.Stack( width=1000, height=1000, controls=[ ft.Container( bgcolor=ft.Colors.RED, width=100, height=100, left=100, top=100, offset=ft.Offset(-1, -1), ) ], ) ) ft.run(main) |
flip | Optional[Flip] | None | Flips this control horizontally and/or vertically. Set to an instance of Flip to mirror across x-axis, y-axis, or both. |
transform | Optional[Transform] | None | Applies a generic matrix transform to this control. Set to an instance of Transform with a recorded Matrix4 to describe arbitrary transform sequences. |
aspect_ratio | Optional[Number] | None | The aspect ratio of the control. It is defined as the ratio of width to height. Note: In current implementation, if aspect_ratio is set, width and height on the same control are ignored for final rendered size. |
animate_opacity | Optional[AnimationValue] | None | 启用 opacity 属性的隐式动画。 详见 此处. |
animate_size | Optional[AnimationValue] | None | 启用此控件尺寸的隐式动画。 If width or height is set, changes to those dimensions are animated. If neither dimension is set, changes to the control's natural size are animated instead. 详见 此处. |
animate_position | Optional[AnimationValue] | None | 启用定位属性(left、right、top、bottom)的隐式动画。 详见 此处. |
animate_align | Optional[AnimationValue] | None | 启用 align 属性的隐式动画。 详见 此处. |
animate_margin | Optional[AnimationValue] | None | 启用 margin 属性的隐式动画。 详见 此处. |
animate_rotation | Optional[AnimationValue] | None | 启用 rotate 属性的隐式动画。 详见 此处. |
animate_scale | Optional[AnimationValue] | None | 启用 scale 属性的隐式动画。 详见 此处. |
animate_offset | Optional[AnimationValue] | None | 启用 offset 属性的隐式动画。 详见 此处. |
size_change_interval | int | 10 | Sampling interval in milliseconds for on_size_change event. Setting to 0 calls on_size_change immediately on every change. |
expand | Annotated[Optional[Union[bool, int]], V.instance_of((bool, int))] | None | 指定此控件是否/如何扩展以填充父布局中的可用空间。 详见 此处. Note: Has effect only if the direct parent of this control is one of the following controls, or their subclasses: Column, Row, View, Page. Raises: ValueError: If it is not of type bool or int. |
expand_loose | bool | False | 允许控件在主轴方向上有可用空间时扩展,但不要求填满所有可用空间。 详见 此处. Note: 若 expand_loose 为 True,则仅当同时满足以下条件时生效: - expand 不为 None,且 - the direct parent of this control is one of the following controls, or their subclasses: Column, Row, View, Page. |
col | ResponsiveNumber | 12 | 若此控件的父控件是 ResponsiveRow,此属性用于决定该控件横跨多少个虚拟列。 可以是数字,也可以是为不同断点配置不同值的字典,例如 col={"sm": 6}。 0 表示在该断点下隐藏控件,不占用任何列。 默认横跨 12 个虚拟列。 \ |
opacity | Annotated[Number, V.between(0.0, 1.0)] | 1.0 | 定义控件的透明度,取值范围 0.0(完全透明)到 1.0(完全不透明)。 抛出异常:ValueError:若不在 0.0 到 1.0 的闭区间内。 |
badge | Optional[BadgeValue] | None | 显示在控件顶部的徽标。 |
visible | bool | True | Every control has visible property which is True by default - control is rendered on the page. Setting visible to False 完全阻止该控件(及其所有子控件)渲染到页面画布上. 隐藏的控件不能通过键盘或鼠标聚焦或选中,也不会触发任何事件。 |
disabled | bool | False | Every control has disabled property which is False by default - control and all its children are enabled. Note: The value of this property will be propagated down to all children controls recursively. Example: For example, if you have a form with multiple entry controls you can disable them all together by disabling container: python ft.Column( disabled = True, controls=[ ft.TextField(), ft.TextField() ] ) |
rtl | bool | False | 控件的文字方向是否为从右到左(RTL)。 |
data | Any | skip_ | 任意类型的自定义数据。 |
key | Optional['KeyValue'] | None | 用于在更新之间保持控件身份稳定的 key。 |
只读属性
| 名称 | 类型 | 默认值 | 说明 |
|---|---|---|---|
parent | Optional['BaseControl'] | — | The direct ancestor(parent) of this control. It defaults to None and will only have a value when this control is mounted (added to the page tree). Page 控件(树的根)为例外 —— 它始终 parent=None。 |
page | 'Page' | — | 此控件所属的页面。 |
事件
| 名称 | 类型 | 默认值 | 说明 |
|---|---|---|---|
on_event | Optional[ft.EventHandler[CandlestickChartEvent]] | None | Called when an event occurs on this chart. |
on_size_change | Optional[EventHandler[LayoutSizeChangeEvent['LayoutControl']]] | None | Called when the size of this control changes. size_change_interval defines how often this event is called. |
on_animation_end | Optional[ControlEventHandler['LayoutControl']] | None | 动画结束时调用,可用于串联多个动画。 事件参数 data 属性包含动画的名称。 详见 此处. |
方法
| 名称 | 类型 | 默认值 | 说明 |
|---|---|---|---|
is_isolated | — | — | Return whether this control is marked as isolated. 被隔离的控件不会参与父级驱动的更新遍历,需要自行管理更新边界。 |
init | — | — | Called after control instance initialization and before the first build / update cycle. 可重写此钩子执行依赖于已初始化字段的轻量设置。 不要在这里调用 update()。 |
build | — | — | 在控件初始化期间调用一次,用于定义其子控件。 page 属性在此方法中可用。 |
before_update | — | — | 每次控件即将更新时调用。 Note: 不要在此处调用 update()。 |
before_event | — | — | 在事件处理器执行前拦截事件。 返回 False 取消分发,返回 True 或 None 则继续正常的事件处理。 |
did_mount | — | — | 在控件挂载到页面树之后调用。 可重写以启动需要已挂载页面的资源,例如订阅、定时器或服务监听。 |
will_unmount | — | — | 在控件从页面树移除之前调用。 可重写以释放 did_mount() 中创建的资源,例如订阅、定时器或外部句柄。 |
get_data_channel | — | — | Resolve the [DataChannel] allocated on the Dart side for this widget. Pattern: on_data_channel_open: Optional[ft.EventHandler[DataChannelOpenEvent]] = None def init(self): self.on_data_channel_open = self._on_open def _on_open(self, e): self._channel = self.get_data_channel(e.channel_id) Idempotent — the underlying Connection caches DataChannels by id, so repeated calls return the same instance. No error path: the id always comes from a framework-fired event, so by the time this runs the channel exists on both sides. |
update | None | — | 请求更新该控件的 UI。 在修改控件状态或属性后调用。 控件必须已挂载到页面,并且未被冻结。 |