Examples: Dialog's response signal handling (#1514)

* example of a dialog's response signal handling

* Apply suggestions Remove comment and one-time use statements

Co-authored-by: Bilal Elmoussaoui <[email protected]>

* Remove one-time use statement

* Remove useless part of ObjectImpl implement statement.

* Add gtk::Dialog in ui xml file. Remove old instance from code.
Allow deprecated use of gtk::Dialog.

* Apply suggestions group import, remove unused comment and blank lines.

Co-authored-by: Bilal Elmoussaoui <[email protected]>

* Replace redundant statements as suggested.

Co-authored-by: Bilal Elmoussaoui <[email protected]>

* Rename gtk::Dialog. Fix multiple identical call in match statement.

* Comment details about types used in callback handler for signal response.

* Rename callback handler popup_dialog in on_counter_notify

* Update examples/composite_dialog/my_app_window/mod.rs

Co-authored-by: jobale <[email protected]>

* Update examples/composite_dialog/my_app_window/mod.rs

---------

Co-authored-by: Bilal Elmoussaoui <[email protected]>

examples/Cargo.toml

@@ -56,6 +56,10 @@ name = "composite_template"
 path = "composite_template/main.rs"
 required-features = ["v4_10"]
 
+[[bin]]
+name = "composite_dialog"
+path = "composite_dialog/main.rs"
+
 [[bin]]
 name = "confetti_snapshot_animation"
 path = "confetti_snapshot_animation/main.rs"

examples/composite_dialog/README.md

@@ -0,0 +1,6 @@
+# Composite Template Dialog
+
+This example shows the use of callbacks, custom and bind property, notify and response signal in a composite
+template situation.
+
+![Screenshot](screenshot.png)

examples/composite_dialog/main.rs

@@ -0,0 +1,16 @@
+mod my_app_window;
+
+use gtk::{glib, prelude::*};
+use my_app_window::MyAppWindow;
+
+fn main() -> glib::ExitCode {
+    let application = gtk::Application::builder()
+        .application_id("com.github.gtk-rs.examples.composite_dialog")
+        .build();
+
+    application.connect_activate(|app| {
+        let win = MyAppWindow::new(app);
+        win.present();
+    });
+    application.run()
+}

examples/composite_dialog/my_app_window/imp.rs

@@ -0,0 +1,41 @@
+use std::cell::Cell;
+
+use gtk::{glib, prelude::*, subclass::prelude::*};
+
+#[derive(Default, gtk::CompositeTemplate, glib::Properties)]
+#[template(file = "window.ui")]
+#[properties(wrapper_type = super::MyAppWindow)]
+pub struct MyAppWindow {
+    #[property(get, set)]
+    counter: Cell<i32>,
+    #[template_child]
+    pub count_label: TemplateChild<gtk::Label>,
+    #[template_child]
+    pub plus: TemplateChild<gtk::Button>,
+    #[template_child]
+    pub minus: TemplateChild<gtk::Button>,
+    #[template_child]
+    pub dialog: TemplateChild<gtk::Dialog>,
+}
+
+#[glib::object_subclass]
+impl ObjectSubclass for MyAppWindow {
+    const NAME: &'static str = "MyAppWindow";
+    type Type = super::MyAppWindow;
+    type ParentType = gtk::ApplicationWindow;
+
+    fn class_init(klass: &mut Self::Class) {
+        klass.bind_template();
+        klass.bind_template_instance_callbacks();
+    }
+
+    fn instance_init(obj: &glib::subclass::InitializingObject<Self>) {
+        obj.init_template();
+    }
+}
+
+#[glib::derived_properties]
+impl ObjectImpl for MyAppWindow {}
+impl WidgetImpl for MyAppWindow {}
+impl WindowImpl for MyAppWindow {}
+impl ApplicationWindowImpl for MyAppWindow {}

examples/composite_dialog/my_app_window/mod.rs

@@ -0,0 +1,69 @@
+// Since Gtk4 v4.10 gtk4::Dialog is deprecated and gtk4-rs's examples minimum version is v4.10
+#[allow(deprecated)]
+mod imp;
+
+use gtk::{glib, prelude::*, subclass::prelude::*};
+
+glib::wrapper! {
+    pub struct MyAppWindow(ObjectSubclass<imp::MyAppWindow>)
+        @extends gtk::Widget, gtk::Window, gtk::ApplicationWindow;
+}
+
+#[gtk::template_callbacks]
+impl MyAppWindow {
+    pub fn new<P: IsA<gtk::Application>>(app: &P) -> Self {
+        glib::Object::builder().property("application", app).build()
+    }
+
+    /// Callback handler for `notify::counter` signal.
+    ///
+    /// When counter property reach 3, a dialog pops up and present the user
+    /// with 2 choices: Set the counter to 6 or reset the counter to 0.
+    #[template_callback]
+    fn on_counter_notify(&self, _p: &glib::ParamSpec) {
+        // Check counter property and create a Dialog.
+        if self.counter() == 3 {
+            self.imp().dialog.present();
+        }
+    }
+
+    /// Handler for dialog's response.
+    ///
+    /// In the callback handler, response type is i32 instead of gtk::ResponseType.
+    /// As the bindings replaces the original i32 to an enum that makes more sense in
+    /// Rust. Although, the template callback can't be changed.
+    ///
+    /// To illustrate this, we can replace `i32` with `gtk::ResponseType` in this handler's signature
+    /// and compile.
+    /// However, at runtime, a crash would occur when the dialog emits a signal response (when clicking
+    /// a dialog's button): This handler signature ask for a `gtk::ResponseType` but receive a `i32`.
+    /// The error message details this discrepancy:  
+    ///
+    /// *Wrong type for argument 1 in template callback \`counter_choice\`:
+    /// ValueTypeMismatchError { actual: gint, requested: GtkResponseType }*
+    #[template_callback]
+    fn counter_choice(&self, response: i32) {
+        self.imp().dialog.set_visible(false);
+
+        match gtk::ResponseType::from(response) {
+            gtk::ResponseType::Ok => self.set_counter(0),
+            gtk::ResponseType::Other(35) => self.set_counter(6),
+            gtk::ResponseType::DeleteEvent => (),
+            _ => unimplemented!(),
+        }
+    }
+
+    /// Callback handler for gtk::Button plus.
+    #[template_callback]
+    fn add_to_counter(&self, _button: &gtk::Button) {
+        let n = self.counter() + 1;
+        self.set_counter(n);
+    }
+
+    /// Callback handler for gtk::Button minus.
+    #[template_callback]
+    fn sub_to_counter(&self, _button: &gtk::Button) {
+        let n = self.counter() - 1;
+        self.set_counter(n);
+    }
+}

examples/composite_dialog/my_app_window/window.ui

@@ -0,0 +1,84 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<interface>
+  <template class="MyAppWindow" parent="GtkApplicationWindow">
+    <property name="default-height">300</property>
+    <property name="default-width">400</property>
+    <property name="hexpand">True</property>
+    <property name="show-menubar">True</property>
+    <property name="title">Composite Template Dialog</property>
+    <property name="vexpand">True</property>
+    <signal name="notify::counter" handler="on_counter_notify" swapped="true"/>
+    <child>
+      <object class="GtkBox">
+        <property name="halign">center</property>
+        <property name="margin-top">10</property>
+        <property name="spacing">5</property>      
+        <property name="orientation">vertical</property>
+        <child>
+          <object class="GtkLabel">
+            <property name="label">Click until you reach 3</property>
+            <style>
+              <class name="large-title"/>
+            </style>
+          </object>
+        </child>
+        <child>
+          <object class="GtkBox">
+            <property name="halign">center</property>
+            <property name="valign">center</property>
+            <property name="spacing">10</property>      
+            <child>
+              <object class="GtkButton" id="plus">
+                <signal name="clicked" handler="add_to_counter" swapped="true"/>
+                <property name="label">+</property>
+                <property name="focus-on-click">True</property>
+              </object>                                      
+            </child>
+            <child>
+              <object class="GtkButton" id="minus">
+                <signal name="clicked" handler="sub_to_counter" swapped="true"/>
+                <property name="label">-</property>
+                <property name="focus-on-click">True</property>
+              </object>                                      
+            </child>
+          </object>
+        </child>
+        <child>
+              <object class="GtkLabel" id="count_label">
+                <property name="label"
+                  bind-source="MyAppWindow"
+                  bind-property="counter"
+                  bind-flags="sync-create"/>
+                <property name="justify">center</property>
+                <property name="margin-end">5</property>
+                <property name="margin-start">5</property>
+                <property name="margin-top">20</property>
+                <property name="margin-bottom">5</property>
+              </object>
+        </child>
+      </object>
+    </child>   
+  </template>
+  <object class="GtkDialog" id="dialog">
+    <property name="transient-for">MyAppWindow</property>
+    <property name="title">Counter reach 3</property>
+    <property name="modal">True</property>
+    <signal name="response" handler="counter_choice" swapped="true"/>
+    <child type="action">
+      <object class="GtkButton" id="button_six">
+        <property name="visible">True</property>
+        <property name="label">Set counter to 6</property>
+      </object>
+    </child>
+    <child type="action">
+      <object class="GtkButton" id="button_reset">
+        <property name="visible">True</property>
+        <property name="label">Reset counter</property>
+      </object>
+    </child>
+    <action-widgets>
+      <action-widget response="35">button_six</action-widget>
+      <action-widget response="ok">button_reset</action-widget>
+    </action-widgets>
+  </object>
+</interface>