add Dom request_focus API (#146)

crates/yakui-core/src/dom/mod.rs

@@ -15,6 +15,7 @@ use anymap::AnyMap;
 use thunderdome::Arena;
 
 use crate::id::WidgetId;
+use crate::input::InputState;
 use crate::response::Response;
 use crate::widget::{ErasedWidget, Widget};
 
@@ -32,6 +33,7 @@ struct DomInner {
     removed_nodes: RefCell<Vec<WidgetId>>,
     root: WidgetId,
     globals: RefCell<AnyMap>,
+    pending_focus_request: RefCell<Option<WidgetId>>,
 }
 
 /// A node in the [`Dom`].
@@ -75,13 +77,17 @@ impl Dom {
     }
 
     /// End the DOM's build phase.
-    pub fn finish(&self) {
+    pub fn finish(&self, input: &InputState) {
         log::debug!("Dom::finish()");
 
         let mut nodes = self.inner.nodes.borrow_mut();
         let mut removed_nodes = self.inner.removed_nodes.borrow_mut();
         let root = self.inner.root;
         trim_children(&mut nodes, &mut removed_nodes, root);
+
+        if let Some(widget_id) = self.inner.pending_focus_request.borrow_mut().take() {
+            input.set_selection(Some(widget_id));
+        }
     }
 
     /// Tells how many nodes are currently in the DOM.
@@ -99,6 +105,11 @@ impl Dom {
         self.inner.root
     }
 
+    /// Request focus for the given widget id
+    pub fn request_focus(&self, id: WidgetId) {
+        *self.inner.pending_focus_request.borrow_mut() = Some(id);
+    }
+
     /// Gives a list of all of the nodes that were removed in the last update.
     /// This is used for synchronizing state with the primary DOM storage.
     pub(crate) fn removed_nodes(&self) -> Ref<'_, [WidgetId]> {
@@ -258,6 +269,7 @@ impl DomInner {
             removed_nodes: RefCell::new(Vec::new()),
             stack: RefCell::new(Vec::new()),
             root: WidgetId::new(root),
+            pending_focus_request: RefCell::new(None),
         }
     }
 }

crates/yakui-core/src/response.rs

@@ -23,6 +23,11 @@ impl<T> Response<T> {
     pub fn into_inner(self) -> T {
         self.inner
     }
+
+    /// Request that the widget with this response should receive focus.
+    pub fn request_focus(&self) {
+        crate::context::dom().request_focus(self.id);
+    }
 }
 
 impl<T> Deref for Response<T> {

crates/yakui-core/src/state.rs

@@ -97,7 +97,7 @@ impl Yakui {
     pub fn finish(&mut self) {
         context::unbind_dom();
 
-        self.dom.finish();
+        self.dom.finish(&self.input);
         self.layout.sync_removals(&self.dom.removed_nodes());
         self.layout.calculate_all(&self.dom, &self.input);
         self.input.finish();

crates/yakui/examples/autofocus.rs

@@ -0,0 +1,29 @@
+use yakui::widgets::{Pad, TextBox};
+use yakui::{center, use_state};
+
+pub fn run() {
+    let text = use_state(|| "".to_owned());
+    let autofocus = use_state(|| false);
+
+    center(|| {
+        let mut box1 = TextBox::new(text.borrow().as_str());
+        box1.style.font_size = 60.0;
+        box1.padding = Pad::all(50.0);
+        box1.placeholder = "placeholder".into();
+
+        let response = box1.show();
+
+        if !autofocus.get() {
+            autofocus.set(true);
+            response.request_focus();
+        }
+
+        if let Some(new_text) = response.into_inner().text {
+            text.set(new_text);
+        }
+    });
+}
+
+fn main() {
+    bootstrap::start(run as fn());
+}