bevy/examples/input/text_input.rs
Sam Kirby 91b083bb05
Prevent panic when multiple Enter inputs received in text_input example (#11872)
# Objective

Presently, it is possible to cause the `text_input` example to panic by
pressing enter too quickly. This happens because, under these
circumstances, the `listen_keyboard_input_events` system spawns multiple
text entry entities where the `listen_received_character_events` system
expects there to only ever be one. As this is an example this PR aims to
highlight this risk and mitigate it.

## Solution

Modify the example so that if a text entry has been spawned already
during this run of the system then further Enter input events are
ignored this run.
2024-02-19 16:51:27 +00:00

210 lines
6.3 KiB
Rust

//! Simple text input support
//!
//! Return creates a new line, backspace removes the last character.
//! Clicking toggle IME (Input Method Editor) support, but the font used as limited support of characters.
//! You should change the provided font with another one to test other languages input.
use std::mem;
use bevy::{input::keyboard::KeyboardInput, prelude::*};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup_scene)
.add_systems(
Update,
(
toggle_ime,
listen_ime_events,
listen_received_character_events,
listen_keyboard_input_events,
bubbling_text,
),
)
.run();
}
fn setup_scene(mut commands: Commands, asset_server: Res<AssetServer>) {
commands.spawn(Camera2dBundle::default());
let font = asset_server.load("fonts/FiraMono-Medium.ttf");
commands.spawn(
TextBundle::from_sections([
TextSection {
value: "IME Enabled: ".to_string(),
style: TextStyle {
font: font.clone_weak(),
font_size: 20.0,
..default()
},
},
TextSection {
value: "false\n".to_string(),
style: TextStyle {
font: font.clone_weak(),
font_size: 30.0,
..default()
},
},
TextSection {
value: "IME Active: ".to_string(),
style: TextStyle {
font: font.clone_weak(),
font_size: 20.0,
..default()
},
},
TextSection {
value: "false\n".to_string(),
style: TextStyle {
font: font.clone_weak(),
font_size: 30.0,
..default()
},
},
TextSection {
value: "click to toggle IME, press return to start a new line\n\n".to_string(),
style: TextStyle {
font: font.clone_weak(),
font_size: 18.0,
..default()
},
},
TextSection {
value: "".to_string(),
style: TextStyle {
font,
font_size: 25.0,
..default()
},
},
])
.with_style(Style {
position_type: PositionType::Absolute,
top: Val::Px(10.0),
left: Val::Px(10.0),
..default()
}),
);
commands.spawn(Text2dBundle {
text: Text::from_section(
"".to_string(),
TextStyle {
font: asset_server.load("fonts/FiraMono-Medium.ttf"),
font_size: 100.0,
..default()
},
),
..default()
});
}
fn toggle_ime(
input: Res<ButtonInput<MouseButton>>,
mut windows: Query<&mut Window>,
mut text: Query<&mut Text, With<Node>>,
) {
if input.just_pressed(MouseButton::Left) {
let mut window = windows.single_mut();
window.ime_position = window.cursor_position().unwrap();
window.ime_enabled = !window.ime_enabled;
let mut text = text.single_mut();
text.sections[1].value = format!("{}\n", window.ime_enabled);
}
}
#[derive(Component)]
struct Bubble {
timer: Timer,
}
#[derive(Component)]
struct ImePreedit;
fn bubbling_text(
mut commands: Commands,
mut bubbles: Query<(Entity, &mut Transform, &mut Bubble)>,
time: Res<Time>,
) {
for (entity, mut transform, mut bubble) in bubbles.iter_mut() {
if bubble.timer.tick(time.delta()).just_finished() {
commands.entity(entity).despawn();
}
transform.translation.y += time.delta_seconds() * 100.0;
}
}
fn listen_ime_events(
mut events: EventReader<Ime>,
mut status_text: Query<&mut Text, With<Node>>,
mut edit_text: Query<&mut Text, (Without<Node>, Without<Bubble>)>,
) {
for event in events.read() {
match event {
Ime::Preedit { value, cursor, .. } if !cursor.is_none() => {
status_text.single_mut().sections[5].value = format!("IME buffer: {value}");
}
Ime::Preedit { cursor, .. } if cursor.is_none() => {
status_text.single_mut().sections[5].value = "".to_string();
}
Ime::Commit { value, .. } => {
edit_text.single_mut().sections[0].value.push_str(value);
}
Ime::Enabled { .. } => {
status_text.single_mut().sections[3].value = "true\n".to_string();
}
Ime::Disabled { .. } => {
status_text.single_mut().sections[3].value = "false\n".to_string();
}
_ => (),
}
}
}
fn listen_received_character_events(
mut events: EventReader<ReceivedCharacter>,
mut edit_text: Query<&mut Text, (Without<Node>, Without<Bubble>)>,
) {
for event in events.read() {
edit_text.single_mut().sections[0]
.value
.push_str(&event.char);
}
}
fn listen_keyboard_input_events(
mut commands: Commands,
mut events: EventReader<KeyboardInput>,
mut edit_text: Query<&mut Text, (Without<Node>, Without<Bubble>)>,
) {
for event in events.read() {
match event.key_code {
KeyCode::Enter => {
let mut text = edit_text.single_mut();
if text.sections[0].value.is_empty() {
continue;
}
let old_value = mem::take(&mut text.sections[0].value);
commands.spawn((
Text2dBundle {
text: Text::from_section(old_value, text.sections[0].style.clone()),
..default()
},
Bubble {
timer: Timer::from_seconds(5.0, TimerMode::Once),
},
));
}
KeyCode::Backspace => {
edit_text.single_mut().sections[0].value.pop();
}
_ => continue,
}
}
}