Picker
Pickers enable users to pick an option from a collapsible list of options, often used when the space is limited.
Example
from deephaven import ui
@ui.component
def ui_picker_basic():
option, set_option = ui.use_state(None)
return ui.picker(
"Rarely",
"Sometimes",
"Always",
label="Choose frequency",
selected_key=option,
on_selection_change=set_option,
)
my_picker_basic = ui_picker_basic()
UI recommendations
Recommendations for creating pickers:
- Every picker should have a label specified. Without one, the picker is ambiguous. In the rare case that context is sufficient, the label is unnecessary; you must still include an aria-label via the
aria_label
prop. - Options in the picker should be kept short and concise; multiple lines are strongly discouraged.
- The picker’s width should be set so that the field button does not prevent options being displayed in full.
- The label, menu items, and placeholder text should all be in sentence case.
- A picker’s help text should provide actionable guidance on what to select and how to select it, offering additional context without repeating the label.
- When an error occurs, the help text specified in a picker should be replaced by error text.
- Write error messages in a concise and helpful manner, guiding users to resolve the issue. Error text should be 1-2 short, complete sentences ending with a period.
Data sources
We can use a Deephaven table as a data source to populate the options for pickers. A table automatically uses the first column as both the key and label. If there are duplicate keys, an error will be thrown; to avoid this, a select_distinct
can be used on the table before using it as a picker data source.
from deephaven import ui
from deephaven.plot import express as dx
stocks = dx.data.stocks().select_distinct("Sym")
my_picker_table_source_example = ui.picker(stocks, label="Stock Symbol Picker")
If you wish to specify the keys and labels manually, you can use a ui.item_table_source
to dynamically derive the options from a table.
from deephaven import ui, empty_table
icon_names = ["vsAccount"]
columns = [
"Key=new Integer(i)",
"Label=new String(`Display `+i)",
"Icon=(String) icon_names[0]",
]
column_types = empty_table(20).update(columns)
item_table_source = ui.item_table_source(
column_types,
key_column="Key",
label_column="Label",
icon_column="Icon",
)
my_picker_item_table_source_example = ui.picker(item_table_source, label="User Picker")
Labeling
The picker can be labeled using the label
prop. If no label is provided, an aria_label
must be provided to identify the control for accessibility purposes.
from deephaven import ui
@ui.component
def ui_picker_label_examples():
return [
ui.picker(
ui.item("Option 1"),
ui.item("Option 2"),
ui.item("Option 3"),
label="Pick an option",
),
ui.picker(
ui.item("Option 1"),
ui.item("Option 2"),
ui.item("Option 3"),
ui.item("Option 4"),
aria_label="Pick an option",
),
]
my_picker_label_examples = ui_picker_label_examples()
The is_required
prop and the necessity_indicator
props can be used to show whether selecting an option in the picker is required or optional.
When the necessity_indicator
prop is set to “label”, a localized string will be generated for “(required)” or “(optional)” automatically.
from deephaven import ui
@ui.component
def ui_picker_required_examples():
return [
ui.picker(
ui.item("Option 1"),
ui.item("Option 2"),
ui.item("Option 3"),
label="Pick an option",
is_required=True,
),
ui.picker(
ui.item("Option 1"),
ui.item("Option 2"),
ui.item("Option 3"),
ui.item("Option 4"),
label="Pick an option",
is_required=True,
necessity_indicator="label",
),
ui.picker(
ui.item("Option 1"),
ui.item("Option 2"),
ui.item("Option 3"),
ui.item("Option 4"),
label="Pick an option",
necessity_indicator="label",
),
]
my_picker_required_examples = ui_picker_required_examples()
Selection
In a picker, the default_selected_key
or selected_key
props set a selected option.
from deephaven import ui
@ui.component
def ui_picker_selected_key_examples():
option, set_option = ui.use_state("Option 1")
return [
ui.picker(
ui.item("Option 1"),
ui.item("Option 2"),
ui.item("Option 3"),
default_selected_key="Option 2",
label="Pick an option (uncontrolled)",
),
ui.picker(
ui.item("Option 1"),
ui.item("Option 2"),
ui.item("Option 3"),
ui.item("Option 4"),
selected_key=option,
on_selection_change=set_option,
label="Pick an option (controlled)",
),
]
my_picker_selected_key_examples = ui_picker_selected_key_examples()
Providing a value to the selected_key
prop runs the component in “controlled” mode where the selection state is driven from the provided value. A value of None
can be used to indicate nothing is selected while keeping the component in controlled mode. The default value is ui.types.Undefined
, which causes the component to run in “uncontrolled” mode.
from deephaven import ui
@ui.component
def ui_picker_key_variations():
controlled_value, set_controlled_value = ui.use_state(None)
return [
ui.picker(
"Option 1",
"Option 2",
selected_key=controlled_value,
on_change=set_controlled_value,
label="Key: Controlled",
),
ui.picker(
"Option 1",
"Option 2",
on_change=lambda x: print(x),
label="Key: Undefined",
),
]
my_picker_key_variations = ui_picker_key_variations()
HTML Forms
Pickers can support a name
prop for integration with HTML forms, allowing for easy identification of a value on form submission.
from deephaven import ui
my_picker_name_example = ui.form(
ui.flex(ui.picker(ui.item("Option 1"), ui.item("Option 2"), name="Sample Name"))
)
Sections
Picker supports sections that group options. Sections can be used by wrapping groups of items in a section
element. Each section takes a title
and key
prop.
from deephaven import ui
my_picker_section_example = ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
ui.section(ui.item("Option 3"), ui.item("Option 4"), title="Section 2"),
)
Events
The Picker component supports selection through mouse, keyboard, and touch inputs via the on_selection_change
prop, which receives the selected key as an argument.
from deephaven import ui
@ui.component
def ui_picker_event_example():
value, set_value = ui.use_state("")
return ui.form(
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
on_selection_change=set_value,
)
)
my_picker_event_example = ui_picker_event_example()
Complex items
Items within a picker can include additional content to better convey options. You can add icons, avatars, and descriptions to the children of an ui.item
. When adding a description, set the slot
prop to “description” to differentiate between the text elements.
from deephaven import ui
my_picker_complex_items_example = ui.picker(
ui.item(
ui.icon("vsGithubAlt"),
ui.text("Github"),
ui.text("Github Option", slot="description"),
text_value="Github",
),
ui.item(
ui.icon("vsAzureDevops"),
ui.text("Azure"),
ui.text("Azure Option", slot="description"),
text_value="Azure",
),
)
Loading
The is_loading
prop displays a progress circle indicating that the picker is loading or processing data, which can be used to give immediate visual feedback to users. It also prevents users from interacting with the picker while data is loading, avoiding potential bad states.
from deephaven import ui
@ui.component
def ui_picker_loading_example():
loading, set_loading = ui.use_state("loading")
return ui.form(
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
is_loading=True if loading == "loading" else False,
)
)
my_picker_loading_example = ui_picker_loading_example()
Validation
The is_required
prop ensures that the user selects an option. The related validation_behaviour
prop allows the user to specify aria or native verification.
When the prop is set to “native”, the validation errors block form submission and are displayed as help text automatically.
from deephaven import ui
@ui.component
def ui_picker_validation_behaviour_example():
return ui.form(
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
validation_behavior="native",
is_required=True,
)
)
my_picker_validation_behaviour_example = ui_picker_validation_behaviour_example()
Label position
By default, the position of a picker’s label is above the picker, but it can be moved to the side using the label_position
prop.
from deephaven import ui
@ui.component
def ui_picker_label_position_examples():
return [
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
label="Test Label",
),
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
label="Test Label",
label_position="side",
),
]
my_picker_label_position_examples = ui_picker_label_position_examples()
Quiet state
The is_quiet
prop makes a picker “quiet”. This can be useful when the picker and its corresponding styling should not distract users from surrounding content.
from deephaven import ui
my_picker_is_quiet_example = ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
is_quiet=True,
)
Disabled state
The is_disabled
prop disables a picker to prevent user interaction. This is useful when the picker should be visible but not available for selection.
from deephaven import ui
my_picker_is_disabled_example = ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
is_disabled=True,
)
Help text
A picker can have both a description
and an error_message
. Use the error message to offer specific guidance on how to correct the input.
The is_invalid
prop can be used to set whether the current picker state is valid or invalid.
from deephaven import ui
@ui.component
def ui_picker_help_text_examples():
return [
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
label="Sample Label",
description="Enter a comment.",
),
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
label="Sample Label",
is_invalid=False,
error_message="Sample invalid error message.",
),
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
label="Sample Label",
is_invalid=True,
error_message="Sample invalid error message.",
),
]
my_picker_help_text_examples = ui_picker_help_text_examples()
Contextual help
Using the contextual_help
prop, a ui.contextual_help
can be placed next to the label to provide additional information about the picker.
from deephaven import ui
picker_contextual_help_example = ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
label="Sample Label",
contextual_help=ui.contextual_help(ui.heading("Content tips")),
)
Custom width
The width
prop adjusts the width of a picker, and the max_width
prop enforces a maximum width.
from deephaven import ui
@ui.component
def ui_picker_width_examples():
return [
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
width="size-3600",
),
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
width="size-3600",
max_width="100%",
),
]
my_picker_width_examples = ui_picker_width_examples()
Align and direction
The align
prop sets the text alignment of the options in the picker, while the direction
prop specifies which direction the menu will open.
It is important to note that the popover will not open in the set direction
if there is not enough room to open in that direction.
from deephaven import ui
@ui.component
def ui_picker_alignment_direction_examples():
return ui.flex(
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
align="end",
menu_width="size-3000",
),
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
direction="top",
),
gap="size-150",
direction="column",
padding=40,
)
my_picker_alignment_direction_examples = ui_picker_alignment_direction_examples()
Menu state
The open state of the picker menu can be controlled through the is_open
and default_open
props.
from deephaven import ui
@ui.component
def ui_picker_open_state_examples():
open, set_open = ui.use_state(False)
return [
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
is_open=open,
on_open_change=set_open,
),
ui.picker(
ui.section(ui.item("Option 1"), ui.item("Option 2"), title="Section 1"),
default_open=True,
),
]
my_picker_open_state_examples = ui_picker_open_state_examples()
API Reference
A picker that can be used to select from a list. Children should be one of five types:
- If children are of type Item, they are the dropdown options.
- If children are of type SectionElement, they are the dropdown sections.
- If children are of type Table, the values in the table are the dropdown options.
Returns: BaseElement
The rendered Picker.
Parameters | Type | Default | Description |
---|---|---|---|
*children | str | int | float | bool | BaseElement | Element | Table | PartitionedTable | ItemTableSource | The options to render within the picker. | |
default_selected_key | str | int | float | bool | None | None | The initial selected key in the collection (uncontrolled). |
selected_key | str | int | float | bool | None | UndefinedType | <deephaven.ui.types.types.UndefinedType object> | The currently selected key in the collection (controlled). |
is_quiet | bool | None | None | Whether the TextField should be displayed with a quiet style |
align | Literal['start', 'end'] | 'start' | Alignment of the menu relative to the input target. |
direction | Literal['bottom', 'top'] | 'bottom' | Direction in which the menu should open relative to the Picker. |
should_flip | bool | True | Whether the menu should flip when it reaches the viewport boundaries. |
menu_width | str | float | None | None | Width of the menu. By default, matches width of the trigger. Note that the minimum width of the dropdown is always equal to the trigger's width. |
auto_focus | bool | None | None | Whether the input should be focused on render. |
auto_complete | str | None | None | Describes the type of autocomplete functionality the input should provide if any. |
name | str | None | None | Name of the input, used when submitting an HTML form. |
is_open | bool | None | None | Sets the open state of the menu. |
default_open | bool | None | None | Sets the default open state of the menu. |
is_disabled | bool | None | None | Whether the Picker is disabled. |
is_required | bool | None | None | Whether user input on the Picker is required before form submission. |
is_invalid | bool | None | None | Whether the Picker is in an invalid state. |
validation_behavior | Literal['aria', 'native'] | None | None | Whether to use native HTML form validation to prevent form submission when the value is missing or invalid, or mark the field as required or invalid via ARIA. |
description | Element | None | None | A description for the field. Provides a hint such as specific requirements for what to choose. |
error_message | Element | None | None | An error message for the field. |
label | None | bool | int | str | Element | List[NodeType] | None | A label for the field. |
placeholder | str | None | None | Placeholder text for the input. |
is_loading | bool | None | None | Whether the Picker is in a loading state. |
label_position | Literal['top', 'side'] | 'top' | The label's overall position relative to the element it is labeling. |
label_align | Literal['start', 'end'] | None | None | The label's horizontal alignment relative to the element it is labeling. |
necessity_indicator | Literal['icon', 'label'] | None | None | Whether the required state should be shown as an icon or text. |
contextual_help | Element | None | None | A ContextualHelp element to place next to the label. |
key | str | None | None | A unique identifier used by React to render elements in a list. |