qml: replace context properties and code updates

Most of the qml code in the repository was outdated,
and followed bad practices, like context properties.
Complementary, after the major updates for Qt6
most of the code was not relying on the new ways of
register types (singletons, and using the decorator QmlElement).

Drop the context property usage in the following examples:
- signals/qmltopy1
- signals/qmltopy2
- signals/pytoqml2
- usingmodel
- quickcontrols2/gallery
- textproperties

Additionally:
- all the tests related to context properties
- tutorials/qmlapp
- tutorials/qmlsqlintegration
- Removing 'scrolling' example
- Fixing some flake8 warnings

Change-Id: I649248c0149876bf2bf94e78e27cef7110f42f1d
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Keith Kyzivat <keith.kyzivat@qt.io>

2 files changed, 41 insertions, 35 deletions

diff --git a/examples/declarative/textproperties/main.py b/examples/declarative/textproperties/main.py
index 48a3f1d91..0408313d3 100644
--- a/examples/declarative/textproperties/main.py
+++ b/examples/declarative/textproperties/main.py
@@ -1,6 +1,6 @@
 #############################################################################
 ##
-## Copyright (C) 2018 The Qt Company Ltd.
+## Copyright (C) 2021 The Qt Company Ltd.
 ## Contact: http://www.qt.io/licensing/
 ##
 ## This file is part of the Qt for Python examples of the Qt Toolkit.
@@ -39,14 +39,21 @@
 #############################################################################
 
 import sys
-from os.path import abspath, dirname, join
+from pathlib import Path
 
 from PySide6.QtCore import QObject, Slot
 from PySide6.QtGui import QGuiApplication
-from PySide6.QtQml import QQmlApplicationEngine
+from PySide6.QtQml import QQmlApplicationEngine, QmlElement
 from PySide6.QtQuickControls2 import QQuickStyle
 
 
+# To be used on the @QmlElement decorator
+# (QML_IMPORT_MINOR_VERSION is optional)
+QML_IMPORT_NAME = "io.qt.textproperties"
+QML_IMPORT_MAJOR_VERSION = 1
+
+
+@QmlElement
 class Bridge(QObject):
 
     @Slot(str, result=str)
@@ -95,17 +102,10 @@ if __name__ == '__main__':
     QQuickStyle.setStyle("Material")
     engine = QQmlApplicationEngine()
 
-    # Instance of the Python object
-    bridge = Bridge()
-
-    # Expose the Python object to QML
-    context = engine.rootContext()
-    context.setContextProperty("con", bridge)
-
     # Get the path of the current directory, and then add the name
     # of the QML file, to load it.
-    qmlFile = join(dirname(__file__), 'view.qml')
-    engine.load(abspath(qmlFile))
+    qml_file = Path(__file__).parent / 'view.qml'
+    engine.load(qml_file)
 
     if not engine.rootObjects():
         sys.exit(-1)
diff --git a/examples/declarative/textproperties/view.qml b/examples/declarative/textproperties/view.qml
index 98289a1ba..cb7992e45 100644
--- a/examples/declarative/textproperties/view.qml
+++ b/examples/declarative/textproperties/view.qml
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2018 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: http://www.qt.io/licensing/
 **
 ** This file is part of the Qt for Python examples of the Qt Toolkit.
@@ -39,11 +39,13 @@
 ****************************************************************************/
 
 
-import QtQuick 2.0
-import QtQuick.Layouts 1.11
-import QtQuick.Controls 2.1
-import QtQuick.Window 2.1
-import QtQuick.Controls.Material 2.1
+import QtQuick
+import QtQuick.Layouts
+import QtQuick.Controls
+import QtQuick.Window
+import QtQuick.Controls.Material
+
+import io.qt.textproperties 1.0
 
 ApplicationWindow {
     id: page
@@ -53,6 +55,10 @@ ApplicationWindow {
     Material.theme: Material.Dark
     Material.accent: Material.Red
 
+    Bridge {
+        id: bridge
+    }
+
     GridLayout {
         id: grid
         columns: 2
@@ -78,9 +84,9 @@ ApplicationWindow {
                 Layout.alignment: Qt.AlignLeft
                 text: "Italic"
                 onToggled: {
-                    leftlabel.font.italic = con.getItalic(italic.text)
-                    leftlabel.font.bold = con.getBold(italic.text)
-                    leftlabel.font.underline = con.getUnderline(italic.text)
+                    leftlabel.font.italic = bridge.getItalic(italic.text)
+                    leftlabel.font.bold = bridge.getBold(italic.text)
+                    leftlabel.font.underline = bridge.getUnderline(italic.text)
 
                 }
             }
@@ -89,9 +95,9 @@ ApplicationWindow {
                 Layout.alignment: Qt.AlignLeft
                 text: "Bold"
                 onToggled: {
-                    leftlabel.font.italic = con.getItalic(bold.text)
-                    leftlabel.font.bold = con.getBold(bold.text)
-                    leftlabel.font.underline = con.getUnderline(bold.text)
+                    leftlabel.font.italic = bridge.getItalic(bold.text)
+                    leftlabel.font.bold = bridge.getBold(bold.text)
+                    leftlabel.font.underline = bridge.getUnderline(bold.text)
                 }
             }
             RadioButton {
@@ -99,9 +105,9 @@ ApplicationWindow {
                 Layout.alignment: Qt.AlignLeft
                 text: "Underline"
                 onToggled: {
-                    leftlabel.font.italic = con.getItalic(underline.text)
-                    leftlabel.font.bold = con.getBold(underline.text)
-                    leftlabel.font.underline = con.getUnderline(underline.text)
+                    leftlabel.font.italic = bridge.getItalic(underline.text)
+                    leftlabel.font.bold = bridge.getBold(underline.text)
+                    leftlabel.font.underline = bridge.getUnderline(underline.text)
                 }
             }
             RadioButton {
@@ -110,9 +116,9 @@ ApplicationWindow {
                 text: "None"
                 checked: true
                 onToggled: {
-                    leftlabel.font.italic = con.getItalic(noneradio.text)
-                    leftlabel.font.bold = con.getBold(noneradio.text)
-                    leftlabel.font.underline = con.getUnderline(noneradio.text)
+                    leftlabel.font.italic = bridge.getItalic(noneradio.text)
+                    leftlabel.font.bold = bridge.getBold(noneradio.text)
+                    leftlabel.font.underline = bridge.getUnderline(noneradio.text)
                 }
             }
         }
@@ -135,7 +141,7 @@ ApplicationWindow {
                     highlighted: true
                     Material.accent: Material.Red
                     onClicked: {
-                        leftlabel.color = con.getColor(red.text)
+                        leftlabel.color = bridge.getColor(red.text)
                     }
                 }
                 Button {
@@ -144,7 +150,7 @@ ApplicationWindow {
                     highlighted: true
                     Material.accent: Material.Green
                     onClicked: {
-                        leftlabel.color = con.getColor(green.text)
+                        leftlabel.color = bridge.getColor(green.text)
                     }
                 }
                 Button {
@@ -153,7 +159,7 @@ ApplicationWindow {
                     highlighted: true
                     Material.accent: Material.Blue
                     onClicked: {
-                        leftlabel.color = con.getColor(blue.text)
+                        leftlabel.color = bridge.getColor(blue.text)
                     }
                 }
                 Button {
@@ -162,7 +168,7 @@ ApplicationWindow {
                     highlighted: true
                     Material.accent: Material.BlueGrey
                     onClicked: {
-                        leftlabel.color = con.getColor(nonebutton.text)
+                        leftlabel.color = bridge.getColor(nonebutton.text)
                     }
                 }
             }
@@ -182,7 +188,7 @@ ApplicationWindow {
                     id: slider
                     value: 0.5
                     onValueChanged: {
-                        leftlabel.font.pointSize = con.getSize(value)
+                        leftlabel.font.pointSize = bridge.getSize(value)
                     }
                 }
             }