Easy simple fast create gtk gui calculator rust

tutorials
1 
  1. cargo new calculator
cd calculator
    • Cargo.toml.
    [dependencies]
gtk = "0.9.0"
regl = "0.2.1"
glib = "0.9.0"

  3. **

    use gtk::prelude::*;
use gtk::{Button, Entry, Grid, Label, Window, WindowType};
use std::ops::Add;

struct Calculator {
    entry: Entry,
    operator: Option<String>,
    first_operand: Option<f64>,
}

impl Calculator {
    fn new() -> Self {
        let entry = Entry::new();
        entry.set_editable(false);

        Self {
            entry,
            operator: None,
            first_operand: None,
        }
    }

    fn add_button(&self, grid: &Grid, label: &str, row: usize, col: usize) {
        let button = Button::with_label(label);
        let entry = self.entry.clone();
        
        button.connect_clicked(move |_| {
            entry.set_text(&label);
        });

        grid.attach(&button, col as i32, row as i32, 1, 1);
    }

    fn add_operations(&mut self, grid: &Grid) {
        let calc_op = |operator, entry: &Entry, first_operand: &mut Option<f64>| {
            let current_text = entry.get_text().unwrap();
            if let Ok(value) = current_text.parse::<f64>() {
                *first_operand = Some(value);
                entry.set_text(&operator);
            }
        };

        let operator_buttons = vec![("+", "add"), ("-", "sub"), ("*", "mul"), ("/", "div")];

        for (index, (label, op)) in operator_buttons.iter().enumerate() {
            let entry = self.entry.clone();
            let first_operand = &mut self.first_operand;
            
            let button = Button::with_label(label);
            button.connect_clicked(move |_| {
                calc_op(op, &entry, first_operand);
            });

            grid.attach(&button, index as i32, 5, 1, 1);
        }
    }
}

fn main() {
    gtk::init().expect("Failed to initialize GTK.");

    let window = Window::new(WindowType::Toplevel);
    window.set_title("Calculator");
    window.set_default_size(200, 200);

    let grid = Grid::new();
    let calculator = Calculator::new();
    
    grid.attach(&calculator.entry, 0, 0, 4, 1);

    let buttons = [
        "7", "8", "9",
        "4", "5", "6",
        "1", "2", "3",
        "0", "+", "=",
    ];

    for (index, label) in buttons.iter().enumerate() {
        calculator.add_button(&grid, label, (index / 3) + 1, index % 3);
    }

    window.add(&grid);
    window.connect_delete_event(|_, _| {
        gtk::main_quit();
        Inhibit(false)
    });

    window.show_all();
    gtk::main();
}

  4. **

    cargo run
2

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