Add close fn to device trait

src/app.rs

@@ -84,6 +84,13 @@ impl eframe::App for TemplateApp {
                     if ui.button("Open Device").clicked() {
                         self.device_window_open = true;
                     }
+                    if self.open_device.is_some() {
+                        if ui.button("Close Device").clicked() {
+                            if let Some(dev) = self.open_device.take() {
+                                dev.close();
+                            }
+                        }
+                    }
                     if !is_web {
                         if ui.button("Quit").clicked() {
                             ctx.send_viewport_cmd(egui::ViewportCommand::Close);
@@ -185,7 +192,9 @@ impl eframe::App for TemplateApp {
                         //let mut b = &self._backends.0[self._selected_backend];
                         b.show_device_selection(ui);
                         if ui.add(egui::Button::new("Apply")).clicked() {
-                            drop(self.open_device.take());
+                            if let Some(dev) = self.open_device.take() {
+                                dev.close()
+                            };
                             if let Ok(device) =
                                 b.build_device(self.fft.tx.clone(), self.plots.get_sender())
                             {

src/backend/audio.rs

@@ -48,6 +48,10 @@ impl crate::backend::Device for Audio {
     fn tune(&mut self, _freq: usize) -> anyhow::Result<()> {
         anyhow::bail!("Can't tune this device")
     }
+
+    fn close(self: Box<Self>) {
+        drop(self);
+    }
 }
 
 pub struct AudioBackend {

src/backend/mod.rs

@@ -8,6 +8,7 @@ pub trait Device {
     fn show_settings(&mut self, ui: &mut Ui);
     fn can_tune(&self) -> bool;
     fn tune(&mut self, freq: usize) -> anyhow::Result<()>;
+    fn close(self: Box<Self>);
 }
 pub trait Backend {
     fn display_text(&self) -> &'static str;
@@ -29,14 +30,10 @@ impl Default for Backends {
 
 #[cfg(target_arch = "wasm32")]
 impl Default for Backends {
-    fn default() -> Self {
-        Backends(vec![])
-    }
+    fn default() -> Self {}
 }
 
 #[cfg(target_os = "android")]
 impl Default for Backends {
-    fn default() -> Self {
-        Backends(vec![])
-    }
+    fn default() -> Self {}
 }