异步操作

异步数据获取

use euv::*;

let loading: Signal<bool> = use_signal(|| false);
let loading_updater: Signal<bool> = loading;
let data: Signal<String> = use_signal(|| "".to_string());
let data_updater: Signal<String> = data;
let error: Signal<String> = use_signal(|| "".to_string());
let error_updater: Signal<String> = error;

button {
    onclick: move |_event: NativeEvent| {
        loading_updater.set(true);
        error_updater.set("".to_string());
        let data_updater_clone: Signal<String> = data_updater;
        let loading_updater_clone: Signal<bool> = loading_updater;
        let error_updater_clone: Signal<String> = error_updater;
        wasm_bindgen_futures::spawn_local(async move {
            let window: web_sys::Window = web_sys::window().expect("no global window exists");
            let promise: js_sys::Promise = window.fetch_with_str("https://httpbin.org/get");
            let future: wasm_bindgen_futures::JsFuture = wasm_bindgen_futures::JsFuture::from(promise);
            match future.await {
                Ok(response) => {
                    let resp: web_sys::Response = response.dyn_into().unwrap();
                    let json_promise: js_sys::Promise = resp.json().unwrap();
                    let json_future: wasm_bindgen_futures::JsFuture = wasm_bindgen_futures::JsFuture::from(json_promise);
                    match json_future.await {
                        Ok(json) => {
                            let json_string: String = js_sys::JSON::stringify(&json).unwrap().as_string().unwrap_or_default();
                            data_updater_clone.set(json_string);
                        }
                        Err(_) => {
                            error_updater_clone.set("Failed to parse JSON".to_string());
                        }
                    }
                }
                Err(_) => {
                    error_updater_clone.set("Network request failed".to_string());
                }
            }
            loading_updater_clone.set(false);
        });
    }
    "Fetch Data"
}

提示

使用 wasm_bindgen_futures::spawn_local 在 WASM 中执行异步任务，任务完成后通过信号更新 UI。

注意

异步闭包中使用的信号必须在闭包外克隆一份再移入，否则会导致借用冲突。

加载中...