frontend: base_state: global methods implemented as a trait

Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>

frontend/src/base_state.rs

@@ -0,0 +1,43 @@
+use orbtk::prelude::*;
+
+use crate::{data::PolicyList, keys::*};
+
+/// Provides generic methods to handle states of datatypes (e.g. used in `PolicyList`).
+pub trait BaseState {
+    /// Navigates to the given entity.
+    fn navigate(&self, to: Entity, ctx: &mut Context) {
+	if let Some(old_focused_element) = ctx.window().get::<Global>("global").focused_widget {
+	    let mut old_focused_element = ctx.get_widget(old_focused_element);
+	    old_focused_element.set("focused", false);
+	    old_focused_element.update_theme_by_state(false);
+	}
+	ctx.window().get_mut::<Global>("global").focused_widget = None;
+	ctx.widget().set("visibility", Visibility::Collapsed);
+	ctx.get_widget(to).set("visibility", Visibility::Visible);
+    }
+
+    /// Fetches the text of a widget.
+    fn fetch_text(&self, ctx: &mut Context, entity: Entity) -> Option<String> {
+	let mut widget = ctx.get_widget(entity);
+
+	let entry = widget.get_mut::<String>("text");
+	if entry.is_empty() {
+	    return None;
+	}
+
+	let copy = entry.to_string();
+	entry.clear();
+	Some(copy)
+    }
+
+    // Save the data.
+    fn save(&self, registry: &mut Registry, ctx: &mut Context) {
+	registry
+	    .get::<Settings>("settings")
+	    .save(
+		PROP_POLICY_LIST,
+		ctx.widget().get::<PolicyList>(PROP_POLICY_LIST),
+	    )
+	    .unwrap();
+    }
+}