focus text edit and fix system ordering (#22)

# Objective

This PR makes immediate use of the console a bit more convenient by
focusing the text edit when it is opened. This allows you to ` and type
a command without clicking or tabbing to the text editor.

Additionally, this PR fixes a bug where the ordering of opening and
rendering the UI was indeterminate, causing the closing key press to
sometimes be sent to the text edit window. Now the ordering is fixed and
the console will always be opened or closed before it is rendered.

## Changelog

- The console text edit control will now be focused on console open.

src/lib.rs

@@ -38,8 +38,11 @@ impl Plugin for DevConsolePlugin {
                 Update,
                 (
                     ui::read_logs,
-                    ui::open_close_ui,
-                    ui::render_ui.run_if(|s: Res<ConsoleUiState>| s.open),
+                    (
+                        ui::open_close_ui,
+                        ui::render_ui.run_if(|s: Res<ConsoleUiState>| s.open),
+                    )
+                        .chain(),
                 ),
             );
     }

src/ui.rs

@@ -27,6 +27,8 @@ pub const COMMAND_RESULT_NAME: &str = "console_result";
 pub(crate) struct ConsoleUiState {
     /// Wherever the console is open or not.
     pub(crate) open: bool,
+    /// Whether we have set focus this open or not.
+    pub(crate) text_focus: bool,
     /// A list of all log messages received plus an
     /// indicator indicating if the message is new.
     pub(crate) log: Vec<(LogMessage, bool)>,
@@ -54,6 +56,7 @@ pub(crate) fn open_close_ui(
 ) {
     if key.just_pressed(config.open_key) {
         state.open = !state.open;
+        state.text_focus = false;
     }
 }
 
@@ -94,20 +97,32 @@ pub(crate) fn render_ui(
                     bottom: 5.0,
                 }))
                 .show_inside(ui, |ui| {
+                    let text_edit_id = egui::Id::new("text_edit");
+
                     //We can use a right to left layout, so we can place the text input last and tell it to fill all remaining space
                     ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
                         if ui.button("Submit").clicked() {
                             submit_command(&mut state.command);
+
+                            // Return keyboard focus to the text edit control.
+                            ui.ctx().memory_mut(|mem| mem.request_focus(text_edit_id));
                         }
                         // ui.button is a shorthand command, a similar command exists for text edits, but this is how to manually construct a widget.
                         // doing this also allows access to more options of the widget, rather than being stuck with the default the shorthand picks.
                         let text_edit = egui::TextEdit::singleline(&mut state.command)
+                            .id(text_edit_id)
                             .desired_width(ui.available_width())
                             .margin(egui::Vec2::splat(4.0))
                             .font(config.theme.font.clone())
                             .lock_focus(true);
 
                         ui.add(text_edit);
+
+                        // Each time we open the console, we want to set focus to the text edit control.
+                        if !state.text_focus {
+                            state.text_focus = true;
+                            ui.ctx().memory_mut(|mem| mem.request_focus(text_edit_id));
+                        }
                     });
                 });
             // Now we can fill the remaining minutespace with a scrollarea, which has only the vertical scrollbar enabled and expands to be as big as possible.