Doc: Fix QVariant documentation

Update documentation to not reference API that is obsolete in Qt 6.
Also fix documentation for changed behavior (isNull()), and
fix snippets.

Pick-to: 6.1 6.2
Change-Id: I526efeff63d907bbadd5e8a539ccf237cb992125
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 5 insertions, 9 deletions

diff --git a/src/corelib/doc/snippets/code/src_corelib_kernel_qvariant.cpp b/src/corelib/doc/snippets/code/src_corelib_kernel_qvariant.cpp
index 1df3fa9edb..2dac3aefd7 100644
--- a/src/corelib/doc/snippets/code/src_corelib_kernel_qvariant.cpp
+++ b/src/corelib/doc/snippets/code/src_corelib_kernel_qvariant.cpp
@@ -53,7 +53,6 @@ QDataStream out(...);
 QVariant v(123);                // The variant now contains an int
 int x = v.toInt();              // x = 123
 out << v;                       // Writes a type tag and an int to out
-v = QVariant("hello");          // The variant now contains a QByteArray
 v = QVariant(tr("hello"));      // The variant now contains a QString
 int y = v.toInt();              // y = 0 since v cannot be converted to an int
 QString s = v.toString();       // s = tr("hello")  (see QObject::tr())
@@ -64,16 +63,13 @@ in >> v;                        // Reads an Int variant
 int z = v.toInt();              // z = 123
 qDebug("Type is %s",            // prints "Type is int"
         v.typeName());
-v = v.toInt() + 100;            // The variant now hold the value 223
-v = QVariant(QStringList());
+v = v.toInt() + 100;            // The variant now holds the value 223
+v = QVariant(QStringList());    // The variant now holds a QStringList
 //! [0]
 
-
 //! [1]
-QVariant x, y(QString()), z(QString(""));
-x.convert(QMetaType::Int);
-// x.isNull() == true
-// y.isNull() == true, z.isNull() == false
+QVariant x;                                // x.isNull() == true
+QVariant y = QVariant::fromValue(nullptr); // y.isNull() == true
 //! [1]
 
 
@@ -95,7 +91,7 @@ QVariant v;
 
 v.setValue(5);
 int i = v.toInt();         // i is now 5
-QString s = v.toString()   // s is now "5"
+QString s = v.toString();  // s is now "5"
 
 MyCustomStruct c;
 v.setValue(c);