cursive/examples/mutation.rs

extern crate cursive;

use cursive::Cursive;
use cursive::views::{Dialog, OnEventView, TextView};
use cursive::view::{Offset, Position};
use cursive::traits::*;

fn show_popup(siv: &mut Cursive) {

    // Let's center the popup horizontally, but offset it down a few rows
    siv.screen_mut()
       .add_layer_at(Position::new(Offset::Center, Offset::Parent(3)),
                     Dialog::around(TextView::new("Tak!"))
                         .button("Change", |s| {
                             // Look for a view tagged "text". We _know_ it's there, so unwrap it.
                             s.call_on_id("text", |view: &mut TextView| {
                                let content: String = view.get_content().chars().rev().collect();
                                view.set_content(content);
                             });
                         })
                         .dismiss_button("Ok"));

}

fn main() {
    let mut siv = Cursive::new();

    let content = "Press Q to quit the application.\n\nPress P to open the \
                   popup.";

    siv.add_global_callback('q', |s| s.quit());

    // Let's wrap the view to give it a recognizable ID, so we can look for it.
    // We add the P callback on the textview only (and not globally),
    // so that we can't call it when the popup is already visible.
    siv.add_layer(OnEventView::new(TextView::new(content).with_id("text"))
        .on_event('p', |s| show_popup(s)));


    siv.run();
}