h-gtk: Remember the vertical allingment of the ShowsView.

hammond-gtk/src/stacks/populated.rs

@@ -60,20 +60,30 @@ impl PopulatedStack {
     }
 
     pub fn update_shows(&mut self) -> Result<(), Error> {
+        // The current visible child might change depending on
+        // removal and insertion in the gtk::Stack, so we have
+        // to make sure it will stay the same.
+        let s = self.state;
+        self.replace_shows()?;
+        self.switch_visible(s, gtk::StackTransitionType::None);
+
+        Ok(())
+    }
+
+    pub fn replace_shows(&mut self) -> Result<(), Error> {
         let old = &self.populated.container.clone();
         debug!("Name: {:?}", WidgetExt::get_name(old));
 
+        self.populated
+            .save_alignment()
+            .map_err(|err| error!("Failed to set episodes_view allignment: {}", err))
+            .ok();
+
         let pop = ShowsView::new(self.sender.clone())?;
         self.populated = pop;
         self.stack.remove(old);
         self.stack.add_named(&self.populated.container, "shows");
 
-        // The current visible child might change depending on
-        // removal and insertion in the gtk::Stack, so we have
-        // to make sure it will stay the same.
-        let s = self.state;
-        self.switch_visible(s, gtk::StackTransitionType::None);
-
         old.destroy();
         Ok(())
     }

hammond-gtk/src/widgets/shows_view.rs

@@ -1,16 +1,23 @@
-use failure::Error;
 use gtk;
 use gtk::prelude::*;
 
+use failure::Error;
+use send_cell::SendCell;
+
 use hammond_data::dbqueries;
 use hammond_data::Podcast;
 
 use app::Action;
-use utils::{get_ignored_shows, lazy_load, set_image_from_path};
+use utils::{self, get_ignored_shows, lazy_load, set_image_from_path};
 
 use std::rc::Rc;
 use std::sync::mpsc::Sender;
 use std::sync::Arc;
+use std::sync::Mutex;
+
+lazy_static! {
+    static ref SHOWS_VIEW_VALIGNMENT: Mutex<Option<SendCell<gtk::Adjustment>>> = Mutex::new(None);
+}
 
 #[derive(Debug, Clone)]
 pub struct ShowsView {
@@ -37,33 +44,69 @@ impl Default for ShowsView {
 impl ShowsView {
     pub fn new(sender: Sender<Action>) -> Result<Rc<Self>, Error> {
         let pop = Rc::new(ShowsView::default());
-        pop.init(sender)?;
+        pop.init(sender);
+        // Populate the flowbox with the Podcasts.
+        populate_flowbox(&pop)?;
         Ok(pop)
     }
 
-    pub fn init(&self, sender: Sender<Action>) -> Result<(), Error> {
+    pub fn init(&self, sender: Sender<Action>) {
         self.flowbox.connect_child_activated(move |_, child| {
             on_child_activate(child, &sender)
                 .map_err(|err| error!("Error along flowbox child activation: {}", err))
                 .ok();
         });
-        // Populate the flowbox with the Podcasts.
-        self.populate_flowbox()
     }
 
-    fn populate_flowbox(&self) -> Result<(), Error> {
-        let ignore = get_ignored_shows()?;
-        let podcasts = dbqueries::get_podcasts_filter(&ignore)?;
+    /// Set scrolled window vertical adjustment.
+    #[allow(unused)]
+    fn set_vadjustment(&self) -> Result<(), Error> {
+        let guard = SHOWS_VIEW_VALIGNMENT
+            .lock()
+            .map_err(|err| format_err!("Failed to lock widget align mutex: {}", err))?;
 
-        let flowbox = self.flowbox.clone();
-        let constructor = |parent| ShowsChild::new(&parent).child;
-        let callback = move || flowbox.show_all();
-
-        let flowbox = self.flowbox.clone();
-        lazy_load(podcasts, flowbox, constructor, callback);
+        if let Some(ref sendcell) = *guard {
+            // Copy the vertical scrollbar adjustment from the old view into the new one.
+            sendcell
+                .try_get()
+                .map(|x| utils::smooth_scroll_to(&self.scrolled_window, &x));
+        }
 
         Ok(())
     }
+
+    /// Save the vertical scrollbar position.
+    pub fn save_alignment(&self) -> Result<(), Error> {
+        if let Ok(mut guard) = SHOWS_VIEW_VALIGNMENT.lock() {
+            let adj = self.scrolled_window
+                .get_vadjustment()
+                .ok_or_else(|| format_err!("Could not get the adjustment"))?;
+            *guard = Some(SendCell::new(adj));
+            info!("Saved episodes_view alignment.");
+        }
+
+        Ok(())
+    }
+}
+
+fn populate_flowbox(shows: &Rc<ShowsView>) -> Result<(), Error> {
+    let ignore = get_ignored_shows()?;
+    let podcasts = dbqueries::get_podcasts_filter(&ignore)?;
+
+    let flowbox = shows.flowbox.clone();
+    let constructor = clone!(flowbox => move |parent| {
+        flowbox.show_all();
+        ShowsChild::new(&parent).child
+    });
+
+    let callback = clone!(shows => move || {
+         shows.set_vadjustment()
+              .map_err(|err| error!("Failed to set ShowsView Alignment: {}", err))
+              .ok();
+     });
+
+    lazy_load(podcasts, flowbox, constructor, callback);
+    Ok(())
 }
 
 fn on_child_activate(child: &gtk::FlowBoxChild, sender: &Sender<Action>) -> Result<(), Error> {