polish: exampels

examples/pattern_model.rs

@@ -0,0 +1,191 @@
+//! 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::desktop::wry::application::dpi::LogicalSize;
+use dioxus::events::on::*;
+use dioxus::prelude::*;
+
+const STYLE: &str = include_str!("./assets/calculator.css");
+fn main() {
+    env_logger::init();
+    dioxus::desktop::launch(App, |cfg| {
+        cfg.with_window(|w| {
+            w.with_title("Calculator Demo")
+                .with_resizable(false)
+                .with_inner_size(LogicalSize::new(320.0, 530.0))
+        })
+    })
+    .expect("failed to launch dioxus app");
+}
+
+static App: FC<()> = |cx, props| {
+    let state = use_ref(cx, || Calculator::new());
+
+    let clear_display = state.read().display_value.eq("0");
+    let clear_text = if clear_display { "C" } else { "AC" };
+    let formatted = state.read().formatted_display();
+
+    rsx!(cx, div { id: "wrapper"
+        div { class: "app", style { "{STYLE}" }
+            div { class: "calculator", onkeypress: move |evt| state.write().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.write().clear_display(), "{clear_text}" }
+                            CalculatorKey { name: "key-sign", onclick: move |_| state.write().toggle_sign(), "±"}
+                            CalculatorKey { name: "key-percent", onclick: move |_| state.write().toggle_percent(), "%"}
+                        }
+                        div { class: "digit-keys"
+                            CalculatorKey { name: "key-0", onclick: move |_| state.write().input_digit(0), "0" }
+                            CalculatorKey { name: "key-dot", onclick: move |_|  state.write().input_dot(), "●" }
+                            {(1..10).map(move |k| rsx!{
+                                CalculatorKey { key: "{k}", name: "key-{k}", onclick: move |_|  state.write().input_digit(k), "{k}" }
+                            })}
+                        }
+                    }
+                    div { class: "operator-keys"
+                        CalculatorKey { name:"key-divide", onclick: move |_| state.write().set_operator(Operator::Div), "÷" }
+                        CalculatorKey { name:"key-multiply", onclick: move |_| state.write().set_operator(Operator::Mul), "×" }
+                        CalculatorKey { name:"key-subtract", onclick: move |_| state.write().set_operator(Operator::Sub), "−" }
+                        CalculatorKey { name:"key-add", onclick: move |_| state.write().set_operator(Operator::Add), "+" }
+                        CalculatorKey { name:"key-equals", onclick: move |_| state.write().perform_operation(), "=" }
+                    }
+                }
+            }
+        }
+    })
+};
+
+#[derive(Props)]
+struct CalculatorKeyProps<'a> {
+    name: &'static str,
+    onclick: &'a dyn Fn(MouseEvent),
+}
+
+fn CalculatorKey<'a, 'r>(cx: Context<'a>, props: &'a CalculatorKeyProps) -> DomTree<'a> {
+    cx.render(rsx! {
+        button {
+            class: "calculator-key {props.name}"
+            onclick: {props.onclick}
+            {cx.children()}
+        }
+    })
+}
+
+struct Calculator {
+    display_value: String,
+    operator: Option<Operator>,
+    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::<f64>()
+            .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::<f64>().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::<f64>().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::<f64>().unwrap();
+        self.waiting_for_operand = true;
+    }
+    fn handle_keydown(&mut self, evt: KeyboardEvent) {
+        match evt.key_code() {
+            KeyCode::Backspace => self.backspace(),
+            KeyCode::Num0 => self.input_digit(0),
+            KeyCode::Num1 => self.input_digit(1),
+            KeyCode::Num2 => self.input_digit(2),
+            KeyCode::Num3 => self.input_digit(3),
+            KeyCode::Num4 => self.input_digit(4),
+            KeyCode::Num5 => self.input_digit(5),
+            KeyCode::Num6 => self.input_digit(6),
+            KeyCode::Num7 => self.input_digit(7),
+            KeyCode::Num8 => self.input_digit(8),
+            KeyCode::Num9 => 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),
+            _ => {}
+        }
+    }
+}