Platform & Accessibility¶

Platform¶

Platform is the canonical way to write platform-aware code:

import pythonnative as pn

font = pn.Platform.select(
    {"ios": "Helvetica", "android": "Roboto", "default": None}
)

if pn.Platform.is_ios:
    margin = 16
else:
    margin = 12

Platform.select looks up the current platform first, then "native" (matches iOS and Android), then "default", then the explicit default= argument. Platform.OS is "test" when running off-device, which is useful for skipping native-only code paths in tests.

Window dimensions, safe area, keyboard¶

PythonNative ships three reactive hooks that subscribe to the platform-published metrics in pythonnative.platform_metrics:

@pn.component
def Responsive():
    dims = pn.use_window_dimensions()
    insets = pn.use_safe_area_insets()
    keyboard = pn.use_keyboard_height()

    return pn.Column(
        pn.Text(f"{dims['width']:.0f} × {dims['height']:.0f}"),
        pn.Text(f"Bottom inset: {insets['bottom']:.0f}"),
        pn.Text(f"Keyboard: {keyboard:.0f}"),
        style={"padding": 16, "spacing": 8},
    )

The component re-renders whenever the underlying value actually changes (no spurious renders on no-op updates). For most apps, KeyboardAvoidingView handles the keyboard case for you and you won't need use_keyboard_height directly.

Status bar¶

Mount StatusBar anywhere in the tree (it renders nothing visible) to control style and visibility:

pn.StatusBar(style="light", background_color="#000000")

style is "light" (light icons, dark background), "dark" (dark icons, light background), or "default".

Alerts and pickers¶

Alert.show is the imperative way to present a dialog. Alert.confirm wraps the common confirm/cancel case. The Picker component is implemented on top of Alert.show(style="action_sheet").

Accessibility props¶

Every interactive component (Text, Button, Pressable, TextInput, Image, container views) accepts the same four accessibility kwargs:

Prop	Purpose
`accessibility_label`	Short spoken description for screen readers
`accessibility_hint`	Extra detail (iOS only)
`accessibility_role`	Semantic role (`"button"`, `"link"`, `"image"`, ...)
`accessible`	Override whether the element is exposed to assistive tech

Components like Button supply a sensible default accessibility_role for you.