pub trait UseRefHook {
// Required methods
fn _hooks_ref(&self) -> &RefCell<Vec<Box<dyn Hook>>>;
fn _next_hook_index(&self) -> usize;
// Provided method
fn use_ref<T, F>(&self, initial: F) -> Rc<RefCell<T>>
where T: 'static,
F: FnOnce() -> T { ... }
}Expand description
Trait for using ref hooks
This trait is automatically implemented for any type that implements HasHooks
(which includes all types using #[hook_element]).
Required Methods§
Sourcefn _hooks_ref(&self) -> &RefCell<Vec<Box<dyn Hook>>>
fn _hooks_ref(&self) -> &RefCell<Vec<Box<dyn Hook>>>
Get access to the hooks storage (internal use)
Sourcefn _next_hook_index(&self) -> usize
fn _next_hook_index(&self) -> usize
Get and increment the hook index (internal use)
Provided Methods§
Sourcefn use_ref<T, F>(&self, initial: F) -> Rc<RefCell<T>>where
T: 'static,
F: FnOnce() -> T,
fn use_ref<T, F>(&self, initial: F) -> Rc<RefCell<T>>where
T: 'static,
F: FnOnce() -> T,
Use a ref hook Returns a shared reference to the mutable value
Examples found in repository?
examples/basic.rs (line 34)
13 fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
14 // useState - 管理计数器状态
15 let (count, set_count) = self.use_state(|| 0i32);
16
17 // useMemo - 计算双倍值
18 let count_val = count();
19 let doubled = self.use_memo(|| count_val * 2, [count_val]);
20
21 // useEffect - 副作用，当count变化时执行
22 self.use_effect(
23 || {
24 println!("Effect: count changed to {}", count_val);
25 // 返回可选的清理函数
26 Some(|| {
27 println!("Effect cleanup: previous effect is being cleaned up");
28 })
29 },
30 [count_val],
31 );
32
33 // useRef - 创建一个可变引用，用于存储上一次的值
34 let prev_count_ref = self.use_ref(|| 0i32);
35 let current_count = count_val;
36
37 // 更新引用值
38 if current_count != *prev_count_ref.borrow() {
39 *prev_count_ref.borrow_mut() = current_count;
40 }
41
42 // useCallback - 创建一个记忆化的回调函数
43 let handle_increment = self.use_callback(
44 || {
45 let count_val = current_count;
46 Box::new(move || {
47 println!("Callback executed with count: {}", count_val);
48 count_val + 1
49 }) as Box<dyn Fn() -> i32>
50 },
51 [current_count],
52 );
53
54 div()
55 .flex()
56 .flex_col()
57 .gap_3()
58 .bg(rgb(0x2d2d2d))
59 .size(px(500.0))
60 .justify_center()
61 .items_center()
62 .shadow_lg()
63 .border_1()
64 .border_color(rgb(0x555555))
65 .text_xl()
66 .text_color(rgb(0xffffff))
67 // 计数器显示
68 .child(format!("Count: {}", count()))
69 // 双倍值显示（useMemo）
70 .child(format!("Doubled (useMemo): {}", doubled()))
71 // useRef显示
72 .child(format!(
73 "Previous count (useRef): {}",
74 *prev_count_ref.borrow()
75 ))
76 // 操作说明
77 .child("Check console for effect and callback logs")
78 .child(div().child("click me").id("counter").on_click(cx.listener(
79 move |_this, _, _window, cx| {
80 set_count(count() + 1);
81 cx.notify();
82 },
83 )))
84 // useCallback测试按钮
85 .child(
86 div()
87 .child("test callback")
88 .id("callback-test")
89 .on_click(cx.listener(move |_this, _, _window, _cx| {
90 let result = handle_increment();
91 println!("Callback returned: {}", result);
92 })),
93 )
94 }Dyn Compatibility§
This trait is not dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.