// Example 1: Check if a QVariant object contains a valid integer value QVariant intValue = 123; if (intValue.isValid() && intValue.type() == QVariant::Int) { int num = intValue.toInt(); qDebug() << "Valid integer value: " << num; } else { qDebug() << "Invalid QVariant object"; } // Example 2: Check if a QVariant object contains a valid QString value QVariant strValue = "Hello, world!"; if (strValue.isValid() && strValue.type() == QVariant::String) { QString str = strValue.toString(); qDebug() << "Valid string value: " << str; } else { qDebug() << "Invalid QVariant object"; }These examples use the Qt library package.