WIP: Add "To Do" example

examples/todo/main.rs

@@ -0,0 +1,68 @@
+mod state;
+
+use self::state::{AppState, Event};
+
+use orbtk::prelude::*;
+
+widget! {
+    MainView<AppState> {
+        orientation: Orientation,
+        spacing: f64
+    }
+}
+
+impl Template for MainView {
+    fn template(mut self, id: Entity, ctx: &mut BuildContext) -> Self {
+        let entry = TextBox::create()
+            .vertical_alignment(Alignment::End)
+            .on_activate(move |ctxt, entity| {
+                ctxt.get_mut::<AppState>(id).send(Event::Create(entity));
+            })
+            .build(ctx);
+
+        let notes = Stack::create()
+            .orientation(Orientation::Vertical)
+            .spacing(4)
+            .build(ctx);
+
+        self.state.notes = notes;
+
+        let scroll_viewer = ScrollViewer::create()
+            .scroll_viewer_mode(("disabled", "auto"))
+            .child(notes)
+            .build(ctx);
+
+        self.name("main-view")
+            .orientation(Orientation::Vertical)
+            .margin(4)
+            .child(
+                Container::create()
+                    .child(scroll_viewer)
+                    .child(
+                        ScrollIndicator::create()
+                            .padding(2.0)
+                            .scroll_offset(scroll_viewer)
+                            .build(ctx),
+                    )
+                    .build(ctx)
+            )
+            .child(entry)
+    }
+
+    fn layout(&self) -> Box<dyn Layout> {
+        Box::new(StackLayout::new())
+    }
+}
+
+fn main() {
+    Application::new()
+        .window(|ctx| {
+            Window::create()
+                .title("Orbital To Do")
+                .position((500.0, 500.0))
+                .size(400.0, 400.0)
+                .child(MainView::create().build(ctx))
+                .build(ctx)
+        })
+        .run();
+}

examples/todo/state.rs

@@ -0,0 +1,92 @@
+use orbtk::prelude::*;
+
+use std::collections::VecDeque;
+
+#[derive(Debug)]
+pub enum Event {
+    Create(Entity),
+    Delete(Entity),
+}
+
+#[derive(AsAny, Default)]
+pub struct AppState {
+    events: VecDeque<Event>,
+    pub notes: Entity,
+    count: u32,
+}
+
+impl AppState {
+    fn append_note(&self, ctx: &mut Context, copy: String) {
+        let id = ctx.entity;
+        let bctx = &mut ctx.build_context();
+        let text = TextBox::create().text(copy);
+
+        let container = Stack::create()
+            .orientation(Orientation::Horizontal)
+            .vertical_alignment(Alignment::Start)
+            .child(text.build(bctx))
+            .build(bctx);
+
+        let button = Button::create()
+            .horizontal_alignment(Alignment::End)
+            .text("Delete")
+            .on_click(move |ctxt, _| {
+                ctxt.get_mut::<AppState>(id)
+                    .events
+                    .push_back(Event::Delete(container));
+
+                true
+            })
+            .build(bctx);
+
+        bctx.append_child(container, button);
+        bctx.append_child(self.notes, container);
+    }
+
+    fn fetch_text(ctx: &mut Context, entity: Entity) -> Option<String> {
+        let mut widget = ctx.get_widget(entity);
+
+        let entry = widget.get_mut::<String16>("text");
+        if entry.is_empty() {
+            return None;
+        }
+
+        let copy = entry.to_string();
+        entry.clear();
+        Some(copy)
+    }
+
+    pub fn send(&mut self, event: Event) {
+        self.events.push_back(event);
+    }
+}
+
+impl State for AppState {
+    fn update(&mut self, _: &mut Registry, ctx: &mut Context) {
+        if let Some(event) = self.events.pop_front() {
+            match event {
+                // Create and append the note to the UI.
+                Event::Create(entity) => {
+                    if let Some(copy) = Self::fetch_text(ctx, entity) {
+                        self.append_note(ctx, copy);
+                        let count = self.count + 1;
+                        self.count = count;
+                        if count == 1 {
+                            ctx.widget().set::<f64>("spacing", 12.0);
+                        }
+                    }
+                }
+
+                // Delete the note of the given ID from the UI.
+                Event::Delete(id) => {
+                    ctx.remove_child_from(id, self.notes);
+                    let count = self.count - 1;
+                    self.count = count;
+                    if count == 0 {
+                        ctx.widget().set::<f64>("spacing", 0.0);
+                    }
+                }
+            }
+        }
+    }
+}