examples/squeezer_bin: Mark properties as writable

Fixes #1757

examples/squeezer_bin/main.rs

@@ -14,7 +14,9 @@ fn main() -> glib::ExitCode {
         let mode_switch = gtk::Switch::new();
         let switch_label = gtk::Label::new(Some("keep aspect ratio"));
         let squeezer = SqueezerBin::default();
-        squeezer.set_child(Some(&gtk::Label::new(Some("Hello World!"))));
+        squeezer.set_child(Some(
+            gtk::Label::new(Some("Hello World!")).upcast::<gtk::Widget>(),
+        ));
 
         headerbar.pack_start(&mode_switch);
         headerbar.pack_start(&switch_label);

examples/squeezer_bin/squeezer_bin/imp.rs

@@ -16,12 +16,43 @@ fn child_size(child: &impl IsA<gtk::Widget>) -> ((i32, i32), (i32, i32)) {
 #[derive(Debug, Default, glib::Properties)]
 #[properties(wrapper_type = super::SqueezerBin)]
 pub struct SqueezerBin {
-    #[property(get, explicit_notify)]
+    #[property(get, set = Self::set_child, explicit_notify, nullable)]
     pub(super) child: RefCell<Option<gtk::Widget>>,
-    #[property(get, explicit_notify)]
+    #[property(get, set = Self::set_keep_aspect_ratio, explicit_notify)]
     pub(super) keep_aspect_ratio: Cell<bool>,
 }
 
+impl SqueezerBin {
+    fn set_child(&self, widget: Option<&gtk::Widget>) {
+        if widget == self.child.borrow().as_ref() {
+            return;
+        }
+
+        if let Some(child) = self.child.borrow_mut().take() {
+            child.unparent();
+        }
+
+        if let Some(w) = widget {
+            self.child.replace(Some(w.clone()));
+            w.set_parent(&*self.obj());
+        }
+
+        self.obj().queue_resize();
+        self.obj().notify_child();
+    }
+
+    fn set_keep_aspect_ratio(&self, keep_aspect_ratio: bool) {
+        if self.keep_aspect_ratio.get() == keep_aspect_ratio {
+            return;
+        }
+
+        self.keep_aspect_ratio.set(keep_aspect_ratio);
+
+        self.obj().queue_resize();
+        self.obj().notify_keep_aspect_ratio();
+    }
+}
+
 #[glib::object_subclass]
 impl ObjectSubclass for SqueezerBin {
     const NAME: &'static str = "SqueezerBin";

examples/squeezer_bin/squeezer_bin/mod.rs

@@ -1,6 +1,6 @@
 mod imp;
 
-use gtk::{glib, prelude::*, subclass::prelude::*};
+use gtk::glib;
 
 glib::wrapper! {
     pub struct SqueezerBin(ObjectSubclass<imp::SqueezerBin>)
@@ -12,37 +12,3 @@ impl Default for SqueezerBin {
         glib::Object::new()
     }
 }
-
-impl SqueezerBin {
-    pub fn set_child(&self, widget: Option<&impl IsA<gtk::Widget>>) {
-        let imp = self.imp();
-        let widget = widget.map(|w| w.as_ref());
-        if widget == imp.child.borrow().as_ref() {
-            return;
-        }
-
-        if let Some(child) = imp.child.borrow_mut().take() {
-            child.unparent();
-        }
-
-        if let Some(w) = widget {
-            imp.child.replace(Some(w.clone()));
-            w.set_parent(self);
-        }
-
-        self.queue_resize();
-        self.notify("child")
-    }
-
-    pub fn set_keep_aspect_ratio(&self, keep_aspect_ratio: bool) {
-        let imp = self.imp();
-        if imp.keep_aspect_ratio.get() == keep_aspect_ratio {
-            return;
-        }
-
-        imp.keep_aspect_ratio.set(keep_aspect_ratio);
-
-        self.queue_resize();
-        self.notify("keep-aspect-ratio")
-    }
-}