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-rw-r--r--src/qml/doc/src/qmllanguageref/syntax/objectattributes.qdoc38
-rw-r--r--src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc20
2 files changed, 58 insertions, 0 deletions
diff --git a/src/qml/doc/src/qmllanguageref/syntax/objectattributes.qdoc b/src/qml/doc/src/qmllanguageref/syntax/objectattributes.qdoc
index d789c67fde..207fb53ca0 100644
--- a/src/qml/doc/src/qmllanguageref/syntax/objectattributes.qdoc
+++ b/src/qml/doc/src/qmllanguageref/syntax/objectattributes.qdoc
@@ -50,6 +50,7 @@ The set of QML object-type attribute types is as follows:
\li signal handler attributes
\li method attributes
\li attached properties and attached signal handler attributes
+\li enumeration attributes
\endlist
These attributes are discussed in detail below.
@@ -974,4 +975,41 @@ ListView {
Now \c delegateItem.ListView.isCurrentItem correctly refers to the
\c isCurrentItem attached property of the delegate.
+\section2 Enumeration Attributes
+
+Enumerations provide a fixed set of named choices. They can be declared in QML using the \c enum keyword:
+
+\qml
+// MyText.qml
+Text {
+ enum TextType {
+ Normal,
+ Heading
+ }
+}
+\endqml
+
+As shown above, enumeration types (e.g. \c TextType) and values (e.g. \c Normal) must begin with an uppercase letter.
+
+Values are referred to via \c {<Type>.<EnumerationType>.<Value>} or \c {<Type>.<Value>}.
+
+\qml
+// MyText.qml
+Text {
+ enum TextType {
+ Normal,
+ Heading
+ }
+
+ property int textType: MyText.TextType.Normal
+
+ font.bold: textType == MyText.TextType.Heading
+ font.pixelSize: textType == MyText.TextType.Heading ? 24 : 12
+}
+\endqml
+
+More information on enumeration usage in QML can be found in the \l {QML Basic Types} \l enumeration documentation.
+
+The ability to declare enumerations in QML was introduced in Qt 5.10.
+
*/
diff --git a/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc b/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc
index b506de471f..a5ad6af4a2 100644
--- a/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc
+++ b/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc
@@ -179,6 +179,26 @@ Rectangle {
Now, after the space key is pressed, the rectangle's height will continue
auto-updating to always be three times its width.
+\section3 Debugging overwriting of bindings
+
+A common cause of bugs in QML applications is accidentally overwriting bindings
+with static values from JavaScript statements. To help developers track down
+problems of this kind, the QML engine is able to emit messages whenever a
+binding is lost due to imperative assignments.
+
+In order to generate such messages, you need to enable the informational output
+for the \c{qt.qml.binding.removal} logging category, for instance by calling:
+
+\code
+QLoggingCategory::setFilterRules(QStringLiteral("qt.qml.binding.removal.info=true"));
+\endcode
+
+Please refer to the QLoggingCategory documentation for more information about
+enabling output from logging categories.
+
+Note that is perfectly reasonable in some circumstances to overwrite bindings.
+Any message generated by the QML engine should be treated as a diagnostic aid,
+and not necessarily as evidence of a problem without further investigation.
\section2 Using \c this with Property Binding