Add data-list-view

examples/data-list-view.rs

@@ -0,0 +1,164 @@
+use kas::prelude::*;
+use kas::view::{DataGenerator, DataLen, GeneratorChanges, GeneratorClerk};
+use kas::view::{Driver, ListView};
+use kas::widgets::{column, *};
+use std::collections::HashMap;
+
+#[derive(Clone, Debug)]
+enum Control {
+    Select(usize),
+    Update(usize, String),
+}
+
+#[derive(Debug)]
+struct MyData {
+    last_change: GeneratorChanges<usize>,
+    last_key: usize,
+    active: usize,
+    strings: HashMap<usize, String>,
+}
+impl MyData {
+    fn new() -> Self {
+        MyData {
+            last_change: GeneratorChanges::None,
+            last_key: 0,
+            active: 0,
+            strings: HashMap::new(),
+        }
+    }
+    fn get_string(&self, index: usize) -> String {
+        self.strings
+            .get(&index)
+            .cloned()
+            .unwrap_or_else(|| format!("Entry #{}", index + 1))
+    }
+    fn handle(&mut self, control: Control) {
+        match control {
+            Control::Select(index) => {
+                self.last_change = GeneratorChanges::Any;
+                self.active = index;
+            }
+            Control::Update(index, text) => {
+                self.last_change = GeneratorChanges::Range(index..index + 1);
+                self.last_key = self.last_key.max(index);
+                self.strings.insert(index, text);
+            }
+        };
+    }
+}
+
+type MyItem = (usize, String); // (active index, entry's text)
+
+#[derive(Debug)]
+struct ListEntryGuard(usize);
+impl EditGuard for ListEntryGuard {
+    type Data = MyItem;
+
+    fn update(edit: &mut EditField<Self>, cx: &mut ConfigCx, data: &MyItem) {
+        if !edit.has_edit_focus() {
+            edit.set_string(cx, data.1.to_string());
+        }
+    }
+
+    fn activate(edit: &mut EditField<Self>, cx: &mut EventCx, _: &MyItem) -> IsUsed {
+        cx.push(Control::Select(edit.guard.0));
+        Used
+    }
+
+    fn edit(edit: &mut EditField<Self>, cx: &mut EventCx, _: &MyItem) {
+        cx.push(Control::Update(edit.guard.0, edit.clone_string()));
+    }
+}
+
+#[impl_self]
+mod ListEntry {
+    // The list entry
+    #[widget]
+    #[layout(column! [
+        row! [self.label, self.radio],
+        self.edit,
+    ])]
+    struct ListEntry {
+        core: widget_core!(),
+        #[widget(&())]
+        label: Label<String>,
+        #[widget]
+        radio: RadioButton<MyItem>,
+        #[widget]
+        edit: EditBox<ListEntryGuard>,
+    }
+
+    impl Events for Self {
+        type Data = MyItem;
+    }
+}
+
+struct ListEntryDriver;
+impl Driver<usize, MyItem> for ListEntryDriver {
+    type Widget = ListEntry;
+
+    fn make(&mut self, key: &usize) -> Self::Widget {
+        let n = *key;
+        ListEntry {
+            core: Default::default(),
+            label: Label::new(format!("Entry number {}", n + 1)),
+            radio: RadioButton::new_msg(
+                "display this entry",
+                move |_, data: &MyItem| data.0 == n,
+                move || Control::Select(n),
+            ),
+            edit: EditBox::new(ListEntryGuard(n)).with_width_em(18.0, 30.0),
+        }
+    }
+
+    fn navigable(_: &Self::Widget) -> bool {
+        false
+    }
+}
+
+#[derive(Default)]
+struct Generator;
+impl DataGenerator<usize> for Generator {
+    type Data = MyData;
+    type Key = usize;
+    type Item = MyItem;
+
+    fn update(&mut self, data: &Self::Data) -> GeneratorChanges<usize> {
+        // We assume that `MyData::handle` has only been called once since this
+        // method was last called.
+        data.last_change.clone()
+    }
+
+    fn len(&self, data: &Self::Data, lbound: usize) -> DataLen<usize> {
+        DataLen::LBound((data.active.max(data.last_key) + 1).max(lbound))
+    }
+
+    fn key(&self, _: &Self::Data, index: usize) -> Option<Self::Key> {
+        Some(index)
+    }
+
+    fn generate(&self, data: &Self::Data, key: &usize) -> Self::Item {
+        (data.active, data.get_string(*key))
+    }
+}
+
+fn main() -> kas::runner::Result<()> {
+    env_logger::init();
+
+    let clerk = GeneratorClerk::new(Generator::default());
+    let list = ListView::down(clerk, ListEntryDriver);
+    let tree = column![
+        "Contents of selected entry:",
+        Text::new(|_, data: &MyData| data.get_string(data.active)),
+        Separator::new(),
+        ScrollBars::new(list).with_fixed_bars(false, true),
+    ];
+
+    let ui = tree
+        .with_state(MyData::new())
+        .on_message(|_, data, control| data.handle(control));
+
+    let window = Window::new(ui, "Data list view");
+
+    kas::runner::Runner::new(())?.with(window).run()
+}

src/SUMMARY.md

@@ -7,4 +7,4 @@
 - [Configuration](config.md)
 - [Calculator: make_widget and grid](calculator.md)
 - [Custom widgets](custom-widget.md)
-- [Data models](data-models.md)
+- [Data list view](data-list-view.md)