//! Example: Calculator //! ------------------- //! //! Some components benefit through the use of "Models". Models are a single block of encapsulated state that allow mutative //! methods to be performed on them. Dioxus exposes the ability to use the model pattern through the "use_model" hook. //! //! Models are commonly used in the "Model-View-Component" approach for building UI state. //! //! `use_model` is basically just a fancy wrapper around set_state, but saves a "working copy" of the new state behind a //! RefCell. To modify the working copy, you need to call "get_mut" which returns the RefMut. This makes it easy to write //! fully encapsulated apps that retain a certain feel of native Rusty-ness. A calculator app is a good example of when this //! is useful. //! //! Do note that "get_mut" returns a `RefMut` (a lock over a RefCell). If two `RefMut`s are held at the same time (ie in a loop) //! the RefCell will panic and crash. You can use `try_get_mut` or `.modify` to avoid this problem, or just not hold two //! RefMuts at the same time. use dioxus::events::on::*; use dioxus::prelude::*; use dioxus_core as dioxus; use dioxus_html as dioxus_elements; use dioxus_web::WebsysRenderer; const STYLE: &str = include_str!("../../../examples/assets/calculator.css"); fn main() { // Setup logging wasm_logger::init(wasm_logger::Config::new(log::Level::Debug)); console_error_panic_hook::set_once(); // Run the app wasm_bindgen_futures::spawn_local(WebsysRenderer::start(App)); } static App: FC<()> = |cx| { let state = use_model(&cx, || Calculator::new()); let clear_display = state.display_value.eq("0"); let clear_text = if clear_display { "C" } else { "AC" }; let formatted = state.formatted_display(); cx.render(rsx! { div { id: "wrapper" div { class: "app", style { "{STYLE}" } div { class: "calculator", onkeypress: move |evt| state.get_mut().handle_keydown(evt), div { class: "calculator-display", "{formatted}"} div { class: "calculator-keypad" div { class: "input-keys" div { class: "function-keys" CalculatorKey { name: "key-clear", onclick: move |_| state.get_mut().clear_display(), "{clear_text}" } CalculatorKey { name: "key-sign", onclick: move |_| state.get_mut().toggle_sign(), "±"} CalculatorKey { name: "key-percent", onclick: move |_| state.get_mut().toggle_percent(), "%"} } div { class: "digit-keys" CalculatorKey { name: "key-0", onclick: move |_| state.get_mut().input_digit(0), "0" } CalculatorKey { name: "key-dot", onclick: move |_| state.get_mut().input_dot(), "●" } {(1..10).map(move |k| rsx!{ CalculatorKey { key: "{k}", name: "key-{k}", onclick: move |_| state.get_mut().input_digit(k), "{k}" } })} } } div { class: "operator-keys" CalculatorKey { name:"key-divide", onclick: move |_| state.get_mut().set_operator(Operator::Div), "÷" } CalculatorKey { name:"key-multiply", onclick: move |_| state.get_mut().set_operator(Operator::Mul), "×" } CalculatorKey { name:"key-subtract", onclick: move |_| state.get_mut().set_operator(Operator::Sub), "−" } CalculatorKey { name:"key-add", onclick: move |_| state.get_mut().set_operator(Operator::Add), "+" } CalculatorKey { name:"key-equals", onclick: move |_| state.get_mut().perform_operation(), "=" } } } } } } }) }; #[derive(Props)] struct CalculatorKeyProps<'a> { name: &'static str, onclick: &'a dyn Fn(MouseEvent), } fn CalculatorKey<'a, 'r>(cx: Context<'a, CalculatorKeyProps<'r>>) -> VNode<'a> { cx.render(rsx! { button { class: "calculator-key {cx.name}" onclick: {cx.onclick} {cx.children()} } }) } #[derive(Clone)] struct Calculator { display_value: String, operator: Option, waiting_for_operand: bool, cur_val: f64, } #[derive(Clone)] enum Operator { Add, Sub, Mul, Div, } impl Calculator { fn new() -> Self { Calculator { display_value: "0".to_string(), operator: None, waiting_for_operand: false, cur_val: 0.0, } } fn formatted_display(&self) -> String { use separator::Separatable; self.display_value .parse::() .unwrap() .separated_string() } fn clear_display(&mut self) { self.display_value = "0".to_string(); } fn input_digit(&mut self, digit: u8) { let content = digit.to_string(); if self.waiting_for_operand || self.display_value == "0" { self.waiting_for_operand = false; self.display_value = content; } else { self.display_value.push_str(content.as_str()); } } fn input_dot(&mut self) { if self.display_value.find(".").is_none() { self.display_value.push_str("."); } } fn perform_operation(&mut self) { if let Some(op) = &self.operator { let rhs = self.display_value.parse::().unwrap(); let new_val = match op { Operator::Add => self.cur_val + rhs, Operator::Sub => self.cur_val - rhs, Operator::Mul => self.cur_val * rhs, Operator::Div => self.cur_val / rhs, }; self.cur_val = new_val; self.display_value = new_val.to_string(); self.operator = None; } } fn toggle_sign(&mut self) { if self.display_value.starts_with("-") { self.display_value = self.display_value.trim_start_matches("-").to_string(); } else { self.display_value = format!("-{}", self.display_value); } } fn toggle_percent(&mut self) { self.display_value = (self.display_value.parse::().unwrap() / 100.0).to_string(); } fn backspace(&mut self) { if !self.display_value.as_str().eq("0") { self.display_value.pop(); } } fn set_operator(&mut self, operator: Operator) { self.operator = Some(operator); self.cur_val = self.display_value.parse::().unwrap(); self.waiting_for_operand = true; } fn handle_keydown(&mut self, evt: KeyboardEvent) { match evt.key_code() { KeyCode::Backspace => self.backspace(), KeyCode::_0 => self.input_digit(0), KeyCode::_1 => self.input_digit(1), KeyCode::_2 => self.input_digit(2), KeyCode::_3 => self.input_digit(3), KeyCode::_4 => self.input_digit(4), KeyCode::_5 => self.input_digit(5), KeyCode::_6 => self.input_digit(6), KeyCode::_7 => self.input_digit(7), KeyCode::_8 => self.input_digit(8), KeyCode::_9 => self.input_digit(9), KeyCode::Add => self.operator = Some(Operator::Add), KeyCode::Subtract => self.operator = Some(Operator::Sub), KeyCode::Divide => self.operator = Some(Operator::Div), KeyCode::Multiply => self.operator = Some(Operator::Mul), _ => {} } } }