new example: autocomplete search box (#502)

new example: autocomplete search box

examples/Cargo.toml

@@ -17,6 +17,7 @@ pretty-bytes = "0.2.2"
 rand = "0.7.3"
 cursive = { path = "../cursive", default-features=false }
 crossbeam-channel = "0.4.2"
+lazy_static = "1.4"
 
 [features]
 default = ["cursive/default"]

examples/src/bin/autocomplete.rs

@@ -0,0 +1,94 @@
+use cursive::align::HAlign;
+use cursive::traits::Scrollable;
+use cursive::view::{Boxable, Identifiable};
+use cursive::views::{Dialog, EditView, LinearLayout, SelectView, TextView};
+use cursive::Cursive;
+use lazy_static::lazy_static;
+
+// This example shows a way to implement a (Google-like) autocomplete search box.
+// Try entering "tok"!
+
+lazy_static! {
+    static ref CITIES: &'static str = include_str!("../../assets/cities.txt");
+}
+
+fn main() {
+    let mut siv = cursive::default();
+
+    siv.add_layer(
+        Dialog::around(
+            LinearLayout::vertical()
+                // the query box is on the top
+                .child(
+                    EditView::new()
+                        // update results every time the query changes
+                        .on_edit(on_edit)
+                        // submit the focused (first) item of the matches
+                        .on_submit(on_submit)
+                        .with_name("query"),
+                )
+                // search results below the input
+                .child(
+                    SelectView::new()
+                        // shows all cities by default
+                        .with_all_str(CITIES.lines())
+                        // Sets the callback for when "Enter" is pressed.
+                        .on_submit(show_next_window)
+                        // Center the text horizontally
+                        .h_align(HAlign::Center)
+                        .with_name("matches")
+                        .scrollable(),
+                )
+                .fixed_height(10),
+        )
+        .button("Quit", Cursive::quit)
+        .title("Where are you from?"),
+    );
+
+    siv.run();
+}
+
+// Update results according to the query
+fn on_edit(siv: &mut Cursive, query: &str, _cursor: usize) {
+    let matches = search_fn(CITIES.lines(), query);
+    // Update the `matches` view with the filtered array of cities
+    siv.call_on_name("matches", |v: &mut SelectView| {
+        v.clear();
+        v.add_all_str(matches);
+    });
+}
+
+// Filter cities with names containing query string. You can implement your own logic here!
+fn search_fn<'a, 'b, T: std::iter::IntoIterator<Item = &'a str>>(
+    items: T,
+    query: &'b str,
+) -> Vec<&'a str> {
+    items
+        .into_iter()
+        .filter(|&item| {
+            let item = item.to_lowercase();
+            let query = query.to_lowercase();
+            item.contains(&query)
+        })
+        .collect()
+}
+
+fn on_submit(siv: &mut Cursive, query: &str) {
+    let matches = siv.find_name::<SelectView>("matches").unwrap();
+    if matches.is_empty() {
+        // not all people live in big cities. If none of the cities in the list matches, use the value of the query.
+        show_next_window(siv, query);
+    } else {
+        // pressing "Enter" without moving the focus into the `matches` view will submit the first match result
+        let city = &*matches.selection().unwrap();
+        show_next_window(siv, city);
+    };
+}
+
+fn show_next_window(siv: &mut Cursive, city: &str) {
+    siv.pop_layer();
+    let text = format!("{} is a great city!", city);
+    siv.add_layer(
+        Dialog::around(TextView::new(text)).button("Quit", |s| s.quit()),
+    );
+}