tree.rs

use std::fmt;

use druid::im::Vector;
use druid::widget::{Button, Either, Flex, Label, Scroll, TextBox};
use druid::{AppLauncher, Data, Lens, LocalizedString, Widget, WidgetExt, WindowDesc};
use druid_widget_nursery::{Tree, TreeNode};

#[derive(Clone, Lens, Data)]
struct Taxonomy {
    name: String,
    editing: bool,
    children: Vector<Taxonomy>, // this makes use of im::Vector now (can derive Data)
}

/// We use Taxonomy as a tree node, implementing both the Data and TreeNode traits.
impl Taxonomy {
    fn new(name: &'static str) -> Self {
        Taxonomy {
            name: name.to_string(),
            editing: false,
            children: Vector::new(),
        }
    }

    fn add_child(mut self, child: Self) -> Self {
        self.children.push_back(child);
        self
    }

    // ADDITION: add a child on a ref (as passed to the on_click closures)
    fn add_child_ref(&mut self, child: Self) {
        self.children.push_back(child);
    }
}

impl Default for Taxonomy {
    fn default() -> Self {
        Taxonomy {
            name: "Life".to_string(),
            editing: false,
            children: Vector::new(),
        }
    }
}

impl TreeNode for Taxonomy {
    fn children_count(&self) -> usize {
        self.children.len()
    }

    fn get_child(&self, index: usize) -> &Taxonomy {
        &self.children[index]
    }

    fn get_child_mut(&mut self, index: usize) -> &mut Taxonomy {
        &mut self.children[index]
    }
}

impl fmt::Display for Taxonomy {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.write_str(&self.name)
    }
}

pub fn main() {
    // Create the main window
    let main_window = WindowDesc::new(ui_builder())
        .title(LocalizedString::new("tree-demo-window-title").with_placeholder("Tree Demo"));

    // Set our initial data.
    // This is an extract from https://en.wikipedia.org/wiki/Linnaean_taxonomy
    let taxonomy = Taxonomy::new("Life")
        .add_child(
            Taxonomy::new("Animalia")
                .add_child(
                    Taxonomy::new("Aves")
                        .add_child(Taxonomy::new("Accipitres"))
                        .add_child(Taxonomy::new("Picae"))
                        .add_child(Taxonomy::new("Passeres")),
                )
                .add_child(
                    Taxonomy::new("Amphibia")
                        .add_child(Taxonomy::new("Reptiles"))
                        .add_child(Taxonomy::new("Serpentes"))
                        .add_child(Taxonomy::new("Nantes")),
                )
                .add_child(Taxonomy::new("Pisces"))
                .add_child(Taxonomy::new("Insecta")),
        )
        .add_child(
            Taxonomy::new("Vegetalia")
                .add_child(Taxonomy::new("Monandria"))
                .add_child(Taxonomy::new("Diandria"))
                .add_child(Taxonomy::new("Heptandria")),
        )
        .add_child(
            Taxonomy::new("Mineralia")
                .add_child(Taxonomy::new("Petræ"))
                .add_child(Taxonomy::new("Fossilia"))
                .add_child(Taxonomy::new("Vitamentra")),
        );

    // start the application
    AppLauncher::with_window(main_window)
        .log_to_console()
        .launch(taxonomy)
        .expect("launch failed");
}

fn ui_builder() -> impl Widget<Taxonomy> {
    Scroll::new(Tree::new(|t: &Taxonomy| {
        // ADDITION: use an Either to build the inner widget, bound to the editing status
        Either::new(
            |data, _env| (*data).editing,
            Flex::row()
                .with_child(
                    TextBox::new()
                        .with_placeholder("new item")
                        .lens(Taxonomy::name),
                )
                .with_child(
                    Button::new("Add").on_click(|ctx, data: &mut Taxonomy, _env| {
                        println!("save {}", data.name);
                        data.editing = false;
                        // ctx.children_changed();
                        // ctx.request_paint();
                        println!("done.");
                    }),
                ),
            Flex::row()
                .with_child(Label::new(t.name.as_str()))
                .with_child(
                    Button::new("Add child").on_click(|ctx, data: &mut Taxonomy, _env| {
                        println!("create child of {}", data.name);
                        data.add_child_ref({
                            let mut child = Taxonomy::new("");
                            child.editing = true;
                            child
                        });
                        // I tried to request_* almost anything here
                        // ctx.children_changed();
                        // ctx.request_paint();
                        println!("done.");
                    }),
                ),
        )
    }))
}