add example

1 files changed, 141 insertions, 0 deletions

diff --git a/examples/cached/src/main.rs b/examples/cached/src/main.rs
new file mode 100644
index 00000000..d7787979
--- /dev/null
+++ b/examples/cached/src/main.rs
@@ -0,0 +1,141 @@
+use iced::widget::{
+    button, column, horizontal_rule, horizontal_space, row, scrollable, text,
+    text_input,
+};
+use iced::{Element, Sandbox};
+use iced::{Length, Settings};
+use iced_lazy::Cached;
+
+use std::collections::HashSet;
+
+pub fn main() -> iced::Result {
+    App::run(Settings::default())
+}
+
+#[derive(Hash)]
+enum SortOrder {
+    Ascending,
+    Descending,
+}
+
+impl std::fmt::Display for SortOrder {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "{}",
+            match self {
+                Self::Ascending => "Ascending",
+                Self::Descending => "Descending",
+            }
+        )
+    }
+}
+
+struct App {
+    options: HashSet<String>,
+    input: String,
+    sort_order: SortOrder,
+}
+
+impl Default for App {
+    fn default() -> Self {
+        Self {
+            options: ["Foo", "Bar", "Baz", "Qux", "Corge", "Waldo", "Fred"]
+                .into_iter()
+                .map(ToString::to_string)
+                .collect(),
+            input: Default::default(),
+            sort_order: SortOrder::Ascending,
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+enum Message {
+    InputChanged(String),
+    ToggleSortOrder,
+    DeleteOption(String),
+    AddOption(String),
+}
+
+impl Sandbox for App {
+    type Message = Message;
+
+    fn new() -> Self {
+        Self::default()
+    }
+
+    fn title(&self) -> String {
+        String::from("Cached - Iced")
+    }
+
+    fn update(&mut self, message: Message) {
+        match message {
+            Message::InputChanged(input) => {
+                self.input = input;
+            }
+            Message::ToggleSortOrder => {
+                self.sort_order = match self.sort_order {
+                    SortOrder::Ascending => SortOrder::Descending,
+                    SortOrder::Descending => SortOrder::Ascending,
+                }
+            }
+            Message::AddOption(option) => {
+                self.options.insert(option);
+                self.input.clear();
+            }
+            Message::DeleteOption(option) => {
+                self.options.remove(&option);
+            }
+        }
+    }
+
+    fn view(&self) -> Element<Message> {
+        let options =
+            Cached::new((&self.sort_order, self.options.len()), || {
+                let mut options = self.options.iter().collect::<Vec<_>>();
+                options.sort_by(|a, b| match self.sort_order {
+                    SortOrder::Ascending => {
+                        a.to_lowercase().cmp(&b.to_lowercase())
+                    }
+                    SortOrder::Descending => {
+                        b.to_lowercase().cmp(&a.to_lowercase())
+                    }
+                });
+
+                options.into_iter().fold(
+                    column![horizontal_rule(1)],
+                    |column, option| {
+                        column
+                            .push(row![
+                                text(option),
+                                horizontal_space(Length::Fill),
+                                button("Delete").on_press(
+                                    Message::DeleteOption(option.to_string(),),
+                                )
+                            ])
+                            .push(horizontal_rule(1))
+                    },
+                )
+            });
+
+        scrollable(
+            column![
+                button(text(format!(
+                    "Toggle Sort Order ({})",
+                    self.sort_order
+                )))
+                .on_press(Message::ToggleSortOrder),
+                options,
+                text_input(
+                    "Add a new option",
+                    &self.input,
+                    Message::InputChanged,
+                )
+                .on_submit(Message::AddOption(self.input.clone())),
+            ]
+            .spacing(20),
+        )
+        .into()
+    }
+}