refactor(examples): add input modes to user input examples

examples/user_input.rs

@@ -29,10 +29,17 @@ use unicode_width::UnicodeWidthStr;
 
 use crate::util::event::{Event, Events};
 
+enum InputMode {
+    Normal,
+    Editing,
+}
+
 /// App holds the state of the application
 struct App {
     /// Current value of the input box
     input: String,
+    /// Current input mode
+    input_mode: InputMode,
     /// History of recorded messages
     messages: Vec<String>,
 }
@@ -41,6 +48,7 @@ impl Default for App {
     fn default() -> App {
         App {
             input: String::new(),
+            input_mode: InputMode::Normal,
             messages: Vec::new(),
         }
     }
@@ -55,7 +63,7 @@ fn main() -> Result<(), failure::Error> {
     let mut terminal = Terminal::new(backend)?;
 
     // Setup event handlers
-    let events = Events::new();
+    let mut events = Events::new();
 
     // Create default app state
     let mut app = App::default();
@@ -66,12 +74,24 @@ fn main() -> Result<(), failure::Error> {
             let chunks = Layout::default()
                 .direction(Direction::Vertical)
                 .margin(2)
-                .constraints([Constraint::Length(3), Constraint::Min(1)].as_ref())
+                .constraints(
+                    [
+                        Constraint::Length(1),
+                        Constraint::Length(3),
+                        Constraint::Min(1),
+                    ]
+                    .as_ref(),
+                )
                 .split(f.size());
+            let help_message = match app.input_mode {
+                InputMode::Normal => "Press q to exit, e to start editing.",
+                InputMode::Editing => "Press Esc to stop editing, Enter to record the message",
+            };
+            Paragraph::new([Text::raw(help_message)].iter()).render(&mut f, chunks[0]);
             Paragraph::new([Text::raw(&app.input)].iter())
                 .style(Style::default().fg(Color::Yellow))
                 .block(Block::default().borders(Borders::ALL).title("Input"))
-                .render(&mut f, chunks[0]);
+                .render(&mut f, chunks[1]);
             let messages = app
                 .messages
                 .iter()
@@ -79,34 +99,47 @@ fn main() -> Result<(), failure::Error> {
                 .map(|(i, m)| Text::raw(format!("{}: {}", i, m)));
             List::new(messages)
                 .block(Block::default().borders(Borders::ALL).title("Messages"))
-                .render(&mut f, chunks[1]);
+                .render(&mut f, chunks[2]);
         })?;
 
         // Put the cursor back inside the input box
         write!(
             terminal.backend_mut(),
             "{}",
-            Goto(4 + app.input.width() as u16, 4)
+            Goto(4 + app.input.width() as u16, 5)
         )?;
         // stdout is buffered, flush it to see the effect immediately when hitting backspace
         io::stdout().flush().ok();
 
         // Handle input
         match events.next()? {
-            Event::Input(input) => match input {
-                Key::Char('q') => {
-                    break;
-                }
-                Key::Char('\n') => {
-                    app.messages.push(app.input.drain(..).collect());
-                }
-                Key::Char(c) => {
-                    app.input.push(c);
-                }
-                Key::Backspace => {
-                    app.input.pop();
-                }
-                _ => {}
+            Event::Input(input) => match app.input_mode {
+                InputMode::Normal => match input {
+                    Key::Char('e') => {
+                        app.input_mode = InputMode::Editing;
+                        events.disable_exit_key();
+                    }
+                    Key::Char('q') => {
+                        break;
+                    }
+                    _ => {}
+                },
+                InputMode::Editing => match input {
+                    Key::Char('\n') => {
+                        app.messages.push(app.input.drain(..).collect());
+                    }
+                    Key::Char(c) => {
+                        app.input.push(c);
+                    }
+                    Key::Backspace => {
+                        app.input.pop();
+                    }
+                    Key::Esc => {
+                        app.input_mode = InputMode::Normal;
+                        events.enable_exit_key();
+                    }
+                    _ => {}
+                },
             },
             _ => {}
         }

examples/util/event.rs

@@ -2,6 +2,7 @@ use std::io;
 use std::sync::mpsc;
 use std::thread;
 use std::time::Duration;
+use std::sync::{Arc, atomic::{AtomicBool, Ordering}};
 
 use termion::event::Key;
 use termion::input::TermRead;
@@ -16,6 +17,7 @@ pub enum Event<I> {
 pub struct Events {
     rx: mpsc::Receiver<Event<Key>>,
     input_handle: thread::JoinHandle<()>,
+    ignore_exit_key: Arc<AtomicBool>,
     tick_handle: thread::JoinHandle<()>,
 }
 
@@ -41,8 +43,10 @@ impl Events {
 
     pub fn with_config(config: Config) -> Events {
         let (tx, rx) = mpsc::channel();
+        let ignore_exit_key = Arc::new(AtomicBool::new(false));
         let input_handle = {
             let tx = tx.clone();
+            let ignore_exit_key = ignore_exit_key.clone();
             thread::spawn(move || {
                 let stdin = io::stdin();
                 for evt in stdin.keys() {
@@ -51,7 +55,7 @@ impl Events {
                             if let Err(_) = tx.send(Event::Input(key)) {
                                 return;
                             }
-                            if key == config.exit_key {
+                            if !ignore_exit_key.load(Ordering::Relaxed) && key == config.exit_key {
                                 return;
                             }
                         }
@@ -72,6 +76,7 @@ impl Events {
         };
         Events {
             rx,
+            ignore_exit_key,
             input_handle,
             tick_handle,
         }
@@ -80,4 +85,12 @@ impl Events {
     pub fn next(&self) -> Result<Event<Key>, mpsc::RecvError> {
         self.rx.recv()
     }
+
+    pub fn disable_exit_key(&mut self) {
+        self.ignore_exit_key.store(true, Ordering::Relaxed);
+    }
+
+    pub fn enable_exit_key(&mut self) {
+        self.ignore_exit_key.store(false, Ordering::Relaxed);
+    }
 }