Update the bindable properties example

- Fix the number of months in each duration
- Move the user Country enum to use QLocale::Territory
- Properly calculate the cost per month to match the UI label
- Use QLocale to format the price display text
- Fix some misspellings and grammar in the doc

Pick-to: 6.2 6.5
Change-Id: I78a64f344073070cd94d5cb4a8a4c7c13afa337f
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

examples/corelib/bindableproperties/bindablesubscription/bindablesubscription.cpp

@@ -13,7 +13,7 @@ BindableSubscription::BindableSubscription(BindableUser *user) : m_user(user)
     m_price.setBinding([this] { return qRound(calculateDiscount() * m_duration * basePrice()); });
 
     m_isValid.setBinding([this] {
-        return m_user->country() != BindableUser::None && m_user->age() > 12;
+        return m_user->country() != BindableUser::Country::AnyCountry && m_user->age() > 12;
     });
 }
 
@@ -44,8 +44,8 @@ double BindableSubscription::calculateDiscount() const
 
 int BindableSubscription::basePrice() const
 {
-    if (m_user->country() == BindableUser::None)
+    if (m_user->country() == BindableUser::Country::AnyCountry)
         return 0;
 
-    return (m_user->country() == BindableUser::Norway) ? 100 : 80;
+    return (m_user->country() == BindableUser::Country::Norway) ? 100 : 80;
 }

examples/corelib/bindableproperties/bindablesubscription/bindablesubscription.h

@@ -14,7 +14,7 @@ class BindableUser;
 class BindableSubscription
 {
 public:
-    enum Duration { Monthly = 1, Quarterly = 4, Yearly = 12 };
+    enum Duration { Monthly = 1, Quarterly = 3, Yearly = 12 };
 
     BindableSubscription(BindableUser *user);
     BindableSubscription(const BindableSubscription &) = delete;

examples/corelib/bindableproperties/bindablesubscription/bindableuser.h

@@ -4,6 +4,7 @@
 #ifndef BINDABLEUSER_H
 #define BINDABLEUSER_H
 
+#include <QLocale>
 #include <QProperty>
 
 //! [bindable-user-class]
@@ -11,13 +12,9 @@
 class BindableUser
 {
 public:
-    enum Country {
+    using Country = QLocale::Territory;
-        None,
-        Finland,
-        Germany,
-        Norway,
-    };
 
+public:
     BindableUser() = default;
     BindableUser(const BindableUser &) = delete;
 
@@ -30,7 +27,7 @@ public:
     QBindable<int> bindableAge() { return &m_age; }
 
 private:
-    QProperty<Country> m_country { None };
+    QProperty<Country> m_country { QLocale::AnyTerritory };
     QProperty<int> m_age { 0 };
 };
 

examples/corelib/bindableproperties/bindablesubscription/main.cpp

@@ -37,15 +37,15 @@ int main(int argc, char *argv[])
     // Initialize user data
     QPushButton *germany = w.findChild<QPushButton *>("btnGermany");
     QObject::connect(germany, &QPushButton::clicked, [&] {
-        user.setCountry(BindableUser::Germany);
+        user.setCountry(BindableUser::Country::Germany);
     });
     QPushButton *finland = w.findChild<QPushButton *>("btnFinland");
     QObject::connect(finland, &QPushButton::clicked, [&] {
-        user.setCountry(BindableUser::Finland);
+        user.setCountry(BindableUser::Country::Finland);
     });
     QPushButton *norway = w.findChild<QPushButton *>("btnNorway");
     QObject::connect(norway, &QPushButton::clicked, [&] {
-        user.setCountry(BindableUser::Norway);
+        user.setCountry(BindableUser::Country::Norway);
     });
 
     QSpinBox *ageSpinBox = w.findChild<QSpinBox *>("ageSpinBox");
@@ -58,7 +58,8 @@ int main(int argc, char *argv[])
     // Track price changes
 //! [update-ui]
     auto priceChangeHandler = subscription.bindablePrice().subscribe([&] {
-        priceDisplay->setText(QString::number(subscription.price()));
+        QLocale lc{QLocale::AnyLanguage, user.country()};
+        priceDisplay->setText(lc.toCurrencyString(subscription.price() / subscription.duration()));
     });
 
     auto priceValidHandler = subscription.bindableIsValid().subscribe([&] {

examples/corelib/bindableproperties/doc/src/bindableproperties.qdoc

@@ -15,7 +15,7 @@
 
     \image bindable_properties_example.png
 
-    \section1 Modelling Subscription System with Signal/Slot Approach
+    \section1 Modeling Subscription System with Signal/Slot Approach
 
     Let's first consider the usual pre-Qt 6 implementation.
     To model the subscription service the \c Subscription class is used:
@@ -48,7 +48,7 @@
 
     \note Both methods need to check if the data is actually changed and
     only then emit the signals. \c setDuration() also needs to recalculate
-    the price, when the duration has changed.
+    the price when the duration has changed.
 
     The \c Subscription is not valid unless the user has a valid country and
     age, so the validity is updated in the following way:
@@ -63,25 +63,25 @@
     \snippet bindableproperties/subscription/user.cpp user-setters
 
     In the \c main() function we initialize instances of \c User and
-    \c Subsrcription:
+    \c Subscription:
 
     \snippet bindableproperties/subscription/main.cpp init
 
-    And do the proper signal-slot connections, to update the \c user and
+    And do the proper signal-slot connections to update the \c user and
-    \c subsrcription data when UI elements change. That is straightforward,
+    \c subscription data when UI elements change. That is straightforward,
     so we will skip this part.
 
-    Next, we connect to \c Subscription::priceChanged(), to update the price
+    Next, we connect to \c Subscription::priceChanged() to update the price
     in the UI when the price changes.
 
     \snippet bindableproperties/subscription/main.cpp connect-price-changed
 
-    We also connect to \c Subscription::isValidChanged(), to disable the price
+    We also connect to \c Subscription::isValidChanged() to disable the price
     display if the subscription isn't valid.
 
     \snippet bindableproperties/subscription/main.cpp connect-validity-changed
 
-    Because the subsrcription price and validity also depend on the user's
+    Because the subscription price and validity also depend on the user's
     country and age, we also need to connect to the \c User::countryChanged()
     and \c User::ageChanged() signals and update \c subscription accordingly.
 
@@ -90,12 +90,12 @@
     This works, but there are some problems:
 
     \list
-    \li There's a lot of boilerplate code for the signal-slot connections,
+    \li There's a lot of boilerplate code for the signal-slot connections
-    to be able to react to changes to \c user or \c subscription. If any of
+    in order to properly track changes to both \c user and \c subscription.
-    the dependencies of the price changes, we need to remember to emit the
+    If any of the dependencies of the price changes, we need to remember to emit the
-    corresponding notifier signals, to recalculate the price and update it in
+    corresponding notifier signals, recalculate the price, and update it in
     the UI.
-    \li If more dependencies for price calculation are added in future, we'll
+    \li If more dependencies for price calculation are added in the future, we'll
     need to add more signal-slot connections and make sure all the dependencies
     are properly updated whenever any of them changes. The overall complexity
     will grow, and the code will become harder to maintain.
@@ -109,7 +109,7 @@
 
     Now let's see how the \l {Qt Bindable Properties} can help to solve the
     same problem. First, let's have a look at the \c BindableSubscription class,
-    which is similar to the \c Subscription class, but is implemented using the
+    which is similar to the \c Subscription class, but is implemented using
     bindable properties:
 
     \snippet bindableproperties/bindablesubscription/bindablesubscription.h bindable-subscription-class
@@ -156,7 +156,7 @@
     changes the value. The subscriptions will stay alive as long as the
     corresponding handlers are alive.
 
-    Also note that the copy constructors of both \c BindableSubsrciption and
+    Also note that the copy constructors of both \c BindableSubscription and
     \c BindableUser are disabled, since it's not defined what should happen
     with their bindings when copying.
 
@@ -166,7 +166,7 @@
     \list
     \li The boilerplate code for the signal-slot connections is removed, the
     dependencies are now tracked automatically.
-    \li The code is easier to maintain. Adding more dependencies in future
+    \li The code is easier to maintain. Adding more dependencies in the future
     will only require adding the corresponding bindable properties and setting
     the binding expressions that reflect the relationships between each other.
     \li The \c Subscription and \c User classes don't depend on the metaobject

examples/corelib/bindableproperties/subscription/main.cpp

@@ -40,15 +40,15 @@ int main(int argc, char *argv[])
     // Initialize user data
     QPushButton *germany = w.findChild<QPushButton *>("btnGermany");
     QObject::connect(germany, &QPushButton::clicked, &user, [&] {
-        user.setCountry(User::Germany);
+        user.setCountry(User::Country::Germany);
     });
     QPushButton *finland = w.findChild<QPushButton *>("btnFinland");
     QObject::connect(finland, &QPushButton::clicked, &user, [&] {
-        user.setCountry(User::Finland);
+        user.setCountry(User::Country::Finland);
     });
     QPushButton *norway = w.findChild<QPushButton *>("btnNorway");
     QObject::connect(norway, &QPushButton::clicked, &user, [&] {
-        user.setCountry(User::Norway);
+        user.setCountry(User::Country::Norway);
     });
 
     QSpinBox *ageSpinBox = w.findChild<QSpinBox *>("ageSpinBox");
@@ -65,7 +65,8 @@ int main(int argc, char *argv[])
 
 //! [connect-price-changed]
     QObject::connect(&subscription, &Subscription::priceChanged, [&] {
-        priceDisplay->setText(QString::number(subscription.price()));
+        QLocale lc{QLocale::AnyLanguage, user.country()};
+        priceDisplay->setText(lc.toCurrencyString(subscription.price() / subscription.duration()));
     });
 //! [connect-price-changed]
 

examples/corelib/bindableproperties/subscription/subscription.cpp

@@ -57,10 +57,10 @@ double Subscription::calculateDiscount() const
 
 int Subscription::basePrice() const
 {
-    if (m_user->country() == User::None)
+    if (m_user->country() == User::Country::AnyTerritory)
         return 0;
 
-    return (m_user->country() == User::Norway) ? 100 : 80;
+    return (m_user->country() == User::Country::Norway) ? 100 : 80;
 }
 
 //! [calculate-base-price]
@@ -70,7 +70,7 @@ int Subscription::basePrice() const
 void Subscription::updateValidity()
 {
     bool isValid = m_isValid;
-    m_isValid = m_user->country() != User::None && m_user->age() > 12;
+    m_isValid = m_user->country() != User::Country::AnyTerritory && m_user->age() > 12;
 
     if (m_isValid != isValid)
         emit isValidChanged();

examples/corelib/bindableproperties/subscription/subscription.h

@@ -15,7 +15,7 @@ class Subscription : public QObject
 {
     Q_OBJECT
 public:
-    enum Duration { Monthly = 1, Quarterly = 4, Yearly = 12 };
+    enum Duration { Monthly = 1, Quarterly = 3, Yearly = 12 };
 
     Subscription(User *user);
 

examples/corelib/bindableproperties/subscription/user.h

@@ -4,6 +4,7 @@
 #ifndef USER_H
 #define USER_H
 
+#include <QLocale>
 #include <QObject>
 
 //! [user-class]
@@ -13,13 +14,9 @@ class User : public QObject
     Q_OBJECT
 
 public:
-    enum Country {
+    using Country = QLocale::Territory;
-        None,
-        Finland,
-        Germany,
-        Norway,
-    };
 
+public:
     Country country() const { return m_country; }
     void setCountry(Country country);
 
@@ -31,8 +28,8 @@ signals:
     void ageChanged();
 
 private:
-    Country m_country = Country::None;
+    Country m_country { QLocale::AnyTerritory };
-    int m_age = 0;
+    int m_age { 0 };
 };
 
 //! [user-class]