Qt Designer/calculatorform example: Remove autoconnected slots

The autoconnection feature is considered error-prone and is warned
about by clazy.
As a drive-by, fix the documentation of the project files.

Task-number: QTBUG-110447
Change-Id: I7ba1bf47487abadfeaf02fd573eb01d0519a2ffd
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>
(cherry picked from commit d3a36cf82e2b7f64eb2e096a87e589479d8ac1df)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

4 files changed, 28 insertions, 40 deletions

diff --git a/examples/designer/calculatorform/CMakeLists.txt b/examples/designer/calculatorform/CMakeLists.txt
index d68752b6a..27856f091 100644
--- a/examples/designer/calculatorform/CMakeLists.txt
+++ b/examples/designer/calculatorform/CMakeLists.txt
@@ -2,7 +2,9 @@ cmake_minimum_required(VERSION 3.16)
 project(calculatorform LANGUAGES CXX)
 
 set(CMAKE_AUTOMOC ON)
+#! [0]
 set(CMAKE_AUTOUIC ON)
+#! [0]
 
 if(NOT DEFINED INSTALL_EXAMPLESDIR)
     set(INSTALL_EXAMPLESDIR "examples")
@@ -12,10 +14,12 @@ set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/designer/calculatorform")
 
 find_package(Qt6 REQUIRED COMPONENTS Core Gui Widgets)
 
+#! [1]
 qt_add_executable(calculatorform
     calculatorform.cpp calculatorform.h calculatorform.ui
     main.cpp
 )
+#! [1]
 
 set_target_properties(calculatorform PROPERTIES
     WIN32_EXECUTABLE TRUE
diff --git a/examples/designer/calculatorform/calculatorform.cpp b/examples/designer/calculatorform/calculatorform.cpp
index 8d5fc88d3..24ce24a61 100644
--- a/examples/designer/calculatorform/calculatorform.cpp
+++ b/examples/designer/calculatorform/calculatorform.cpp
@@ -8,19 +8,15 @@ CalculatorForm::CalculatorForm(QWidget *parent)
     : QWidget(parent)
 {
     ui.setupUi(this);
+    connect(ui.inputSpinBox1, &QSpinBox::valueChanged, this, &CalculatorForm::updateResult);
+    connect(ui.inputSpinBox2, &QSpinBox::valueChanged, this, &CalculatorForm::updateResult);
 }
 //! [0]
 
 //! [1]
-void CalculatorForm::on_inputSpinBox1_valueChanged(int value)
+void CalculatorForm::updateResult()
 {
-    ui.outputWidget->setText(QString::number(value + ui.inputSpinBox2->value()));
+    const int sum = ui.inputSpinBox1->value() + ui.inputSpinBox2->value();
+    ui.outputWidget->setText(QString::number(sum));
 }
 //! [1]
-
-//! [2]
-void CalculatorForm::on_inputSpinBox2_valueChanged(int value)
-{
-    ui.outputWidget->setText(QString::number(value + ui.inputSpinBox1->value()));
-}
-//! [2]
diff --git a/examples/designer/calculatorform/calculatorform.h b/examples/designer/calculatorform/calculatorform.h
index bb301ceaa..9224ba027 100644
--- a/examples/designer/calculatorform/calculatorform.h
+++ b/examples/designer/calculatorform/calculatorform.h
@@ -17,8 +17,7 @@ public:
     explicit CalculatorForm(QWidget *parent = nullptr);
 
 private slots:
-    void on_inputSpinBox1_valueChanged(int value);
-    void on_inputSpinBox2_valueChanged(int value);
+    void updateResult();
 
 private:
     Ui::CalculatorForm ui;
diff --git a/examples/designer/doc/src/calculatorform.qdoc b/examples/designer/doc/src/calculatorform.qdoc
index 32d4ef48f..37d356ac6 100644
--- a/examples/designer/doc/src/calculatorform.qdoc
+++ b/examples/designer/doc/src/calculatorform.qdoc
@@ -10,9 +10,7 @@
 
     The Calculator Form Example shows how to use a form created with
     \QD in an application by using the user interface information from
-    a QWidget subclass.  We use \l{Using a Designer UI File in Your Application}
-    {uic's auto-connection} feature to automatically connect signals
-    from widgets on the form to slots in our code.
+    a QWidget subclass.
 
     \image calculatorform-example.png Screenshot of the Calculator Form example
 
@@ -27,8 +25,14 @@
     result is a UI file describing the form, the widgets used, any signal-slot
     connections between them, and other standard user interface properties.
 
-    To ensure that the example can use this file, we need to include a \c FORMS
-    declaration in the example's project file:
+    To ensure that the example can use this file, we enable the \c CMAKE_AUTOUIC
+    feature and list the UI file in the source files:
+
+    \snippet calculatorform/CMakeLists.txt 0
+    \codeline
+    \snippet calculatorform/CMakeLists.txt 1
+
+    For \c qmake, we need to include a \c FORMS declaration in the example's project file:
 
     \snippet calculatorform/calculatorform.pro 1
 
@@ -49,16 +53,17 @@
 
     \snippet calculatorform/calculatorform.h 1
 
-    Apart from the constructor, the class contains two private slots that
-    are named according to the auto-connection naming convention required
-    by \c uic.
+    Apart from the constructor, the class contains a private slot
+    \c updateResult() that performs the calculation and updates the output
+    widget accordingly.
     The private \c ui member variable refers to the form, and is used to
     access the contents of the user interface.
 
     \section1 CalculatorForm Class Implementation
 
-    The constructor simply calls the base class's constructor and
-    sets up the form's user interface.
+    The constructor simply calls the base class's constructor,
+    sets up the form's user interface and connects
+    the signals \l{QSpinBox::valueChanged()} to the slot \c updateResult().
 
     \snippet calculatorform/calculatorform.cpp 0
 
@@ -66,26 +71,10 @@
     \c this as the argument to this function to use the \c CalculatorForm
     widget itself as the container for the user interface.
 
-    To automatically connect signals from the spin boxes defined in the
-    user interface, we use the naming convention that indicates which
-    widgets and their signals in the user interface should be connected
-    to each slot. The first slot is called whenever the spin box called
-    "inputSpinBox1" in the user interface emits the
-    \l{QSpinBox::valueChanged()}{valueChanged()} signal:
+    Slot \c updateResult() adds the values and sets the result on
+    the output widget:
 
     \snippet calculatorform/calculatorform.cpp 1
 
-    When this occurs, we use the value supplied by the signal to update the
-    output label by setting its new text directly. We access the output label
-    and the other spin box via the class's private \c ui variable.
-
-    The second slot is called whenever the second spin box, called
-    "inputSpinBox2", emits the \l{QSpinBox::valueChanged()}{valueChanged()}
-    signal:
-
-    \snippet calculatorform/calculatorform.cpp 2
-
-    In this case, the value from the first spin box is read and combined
-    with the value supplied by the signal. Again, the output label is
-    updated directly via the \c ui variable.
+    It is called whenever the value of one of the spin boxes changes.
 */