oxivgl 0.1.2

Safe no_std Rust bindings for LVGL — embedded GUI on ESP32 and host SDL2
Documentation 
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#![cfg_attr(target_arch = "xtensa", no_std, no_main)]
#![cfg_attr(
    target_arch = "xtensa",
    feature(impl_trait_in_assoc_type, type_alias_impl_trait)
)]
// SPDX-License-Identifier: MIT OR Apache-2.0
//! Translation 2 — Language switching via dropdown with auto-updating labels
//!
//! Registers a static translation pack with animal names in English, German,
//! and Spanish. A dropdown lets the user pick the language; labels bound to
//! translation tags update automatically when the language changes.
//!
//! Requires `LV_USE_TRANSLATION = 1` in `lv_conf.h`.

use oxivgl::view::NavAction;
use oxivgl::{
    enums::EventCode,
    event::Event,
    layout::{FlexAlign, FlexFlow},
    translation::{self, StaticCStr as S},
    view::{register_event_on, View},
    widgets::{Obj, Dropdown, Label, WidgetError},
};

// Language tag strings used for index-based language switching.
static LANG_CSTR: [&core::ffi::CStr; 3] = [c"English", c"Deutsch", c"Espanol"];

// NULL-terminated language and tag arrays — LVGL stores these pointers directly.
static LANGUAGES: [S; 4] = [
    S::from_cstr(c"English"),
    S::from_cstr(c"Deutsch"),
    S::from_cstr(c"Espanol"),
    S::NULL,
];
static TAGS: [S; 5] = [
    S::from_cstr(c"tiger"),
    S::from_cstr(c"lion"),
    S::from_cstr(c"rabbit"),
    S::from_cstr(c"elephant"),
    S::NULL,
];
// Translations flattened row-major: [en_tiger, de_tiger, es_tiger, en_lion, ...]
static TRANSLATIONS: [S; 12] = [
    S::from_cstr(c"The Tiger"),
    S::from_cstr(c"Der Tiger"),
    S::from_cstr(c"El Tigre"),
    S::from_cstr(c"The Lion"),
    S::from_cstr(c"Der Loewe"),
    S::from_cstr(c"El Leon"),
    S::from_cstr(c"The Rabbit"),
    S::from_cstr(c"Das Kaninchen"),
    S::from_cstr(c"El Conejo"),
    S::from_cstr(c"The Elephant"),
    S::from_cstr(c"Der Elefant"),
    S::from_cstr(c"El Elefante"),
];

#[derive(Default)]
struct Translation2 {
    dd: Option<Dropdown<'static>>,
    _lbl_tiger: Option<Label<'static>>,
    _lbl_lion: Option<Label<'static>>,
    _lbl_rabbit: Option<Label<'static>>,
    _lbl_elephant: Option<Label<'static>>,
}

impl View for Translation2 {
    fn create(&mut self, container: &Obj<'static>) -> Result<(), WidgetError> {

        // Arrange container items in a centered column.
        container
            .set_flex_flow(FlexFlow::Column)
            .set_flex_align(FlexAlign::Center, FlexAlign::Center, FlexAlign::Center);

        // Register static translation pack.
        translation::add_static(&LANGUAGES, &TAGS, &TRANSLATIONS);

        // Language selector dropdown.
        let dd = Dropdown::new(container)?;
        dd.set_options("English\nDeutsch\nEspanol");
        dd.bubble_events();

        // Labels with translation tags — auto-update on language change.
        let lbl_tiger = Label::new(container)?;
        lbl_tiger.set_translation_tag("tiger");

        let lbl_lion = Label::new(container)?;
        lbl_lion.set_translation_tag("lion");

        let lbl_rabbit = Label::new(container)?;
        lbl_rabbit.set_translation_tag("rabbit");

        let lbl_elephant = Label::new(container)?;
        lbl_elephant.set_translation_tag("elephant");

        // Set initial language to English.
        translation::set_language(c"English");

                self.dd = Some(dd);
        self._lbl_tiger = Some(lbl_tiger);
        self._lbl_lion = Some(lbl_lion);
        self._lbl_rabbit = Some(lbl_rabbit);
        self._lbl_elephant = Some(lbl_elephant);
        Ok(())
    }

    fn register_events(&mut self) {
        if let Some(ref dd) = self.dd {
            register_event_on(self, dd.handle());
        }
    }

    fn on_event(&mut self, event: &Event) -> NavAction {
        if event.code() == EventCode::VALUE_CHANGED {
            if let Some(ref dd) = self.dd {
                let idx = dd.get_selected() as usize;
                if idx < LANG_CSTR.len() {
                    translation::set_language(LANG_CSTR[idx]);
                }
            }
        }
        NavAction::None
    }

    fn update(&mut self) -> Result<NavAction, WidgetError> {
        Ok(NavAction::None)
    }
}

oxivgl_examples_common::example_main!(Translation2::default());