add single_line example

examples/single_line.rs

@@ -0,0 +1,88 @@
+use crossterm::event::{DisableMouseCapture, EnableMouseCapture};
+use crossterm::terminal::{
+    disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen,
+};
+use std::io;
+use tui::backend::CrosstermBackend;
+use tui::layout::{Constraint, Layout};
+use tui::style::{Color, Style};
+use tui::widgets::{Block, Borders};
+use tui::Terminal;
+use tui_textarea::{Input, Key, TextArea};
+
+fn update(textarea: &mut TextArea) -> bool {
+    if let Err(err) = textarea.lines()[0].parse::<f64>() {
+        textarea.set_style(Style::default().fg(Color::LightRed));
+        textarea.set_block(
+            Block::default()
+                .borders(Borders::ALL)
+                .title(format!("ERROR: {}", err)),
+        );
+        false
+    } else {
+        textarea.set_style(Style::default().fg(Color::LightGreen));
+        textarea.set_block(Block::default().borders(Borders::ALL).title("OK"));
+        true
+    }
+}
+
+fn main() -> io::Result<()> {
+    let stdout = io::stdout();
+    let mut stdout = stdout.lock();
+
+    enable_raw_mode()?;
+    crossterm::execute!(stdout, EnterAlternateScreen, EnableMouseCapture)?;
+    let backend = CrosstermBackend::new(stdout);
+    let mut term = Terminal::new(backend)?;
+
+    let mut textarea = TextArea::default();
+    textarea.set_block(
+        Block::default()
+            .borders(Borders::ALL)
+            .title("Single Line Input"),
+    );
+    textarea.set_cursor_line_style(Style::default());
+    let layout =
+        Layout::default().constraints([Constraint::Length(3), Constraint::Min(1)].as_slice());
+    let mut is_valid = update(&mut textarea);
+
+    loop {
+        term.draw(|f| {
+            let chunks = layout.split(f.size());
+            let widget = textarea.widget();
+            f.render_widget(widget, chunks[0]);
+        })?;
+
+        match Input::from(crossterm::event::read()?) {
+            Input { key: Key::Esc, .. } => break,
+            Input {
+                key: Key::Enter, ..
+            } if is_valid => break,
+            Input {
+                key: Key::Char('m'),
+                ctrl: true,
+                ..
+            }
+            | Input {
+                key: Key::Enter, ..
+            } => {}
+            input => {
+                // TextArea::input returns if the input modified its text
+                if textarea.input(input) {
+                    is_valid = update(&mut textarea);
+                }
+            }
+        }
+    }
+
+    disable_raw_mode()?;
+    crossterm::execute!(
+        term.backend_mut(),
+        LeaveAlternateScreen,
+        DisableMouseCapture
+    )?;
+    term.show_cursor()?;
+
+    println!("Input: {:?}", textarea.lines()[0]);
+    Ok(())
+}