Encapsulates a value in JSON. More...

Public Types
enum	Type

Public Methods
	QJsonValue (bool b)

	QJsonValue (const QJsonValue &other)

	QJsonValue (double n)

	QJsonValue (int n)

	QJsonValue (qint64 n)

	QJsonValue (QJsonArray array)

	QJsonValue (QJsonObject object)

	QJsonValue (QString str)

	QJsonValue (Type type=Null)

	~QJsonValue ()

bool	isArray () const

bool	isBool () const

bool	isDouble () const

bool	isNull () const

bool	isObject () const

bool	isString () const

bool	isUndefined () const

bool	operator!= (const QJsonValue &other) const

QJsonValue &	operator= (const QJsonValue &other)

bool	operator== (const QJsonValue &other) const

QJsonArray	toArray () const

QJsonArray	toArray (const QJsonArray &defaultValue) const

bool	toBool (bool defaultValue=false) const

double	toDouble (double defaultValue=0) const

int	toInt (int defaultValue=0) const

QJsonObject	toObject () const

QJsonObject	toObject (const QJsonObject &defaultValue) const

QString	toString (const QString &defaultValue=QString ()) const

QVariant	toVariant () const

Type	type () const

Static Public Methods
static QJsonValue	fromVariant (const QVariant &variant)

Detailed Description

The QJsonValue class encapsulates the value type available in a JSON format. A value can only be one of the data types shown below.

bool
double
string
array
object
null

There is one extra QJsonValue which is used to represent undefined values.

The data type of a value can be queried using type() or with the methods like isBool(), isDouble(), isString(), isArray(), and isObject(). The method isUndefined() is used to query if the data type is Type::Undefined.

The value stored in a QJsonValue can be retrieved by using toBool(), toDouble(), toInt(), toString(), toArray(), and toObject().

See also: JSON Support

Member Enumeration Documentation

enum QJsonValue::Type

This enum describes the type of the JSON value.

Constant	Value	Description
`QJsonValue::Null`	`0x0`
`QJsonValue::Bool`	`0x1`	toBool() to convert to a bool
`QJsonValue::Double`	`0x2`	toDouble() to convert to a double
`QJsonValue::String`	`0x3`	toString() to convert to a QString
`QJsonValue::Array`	`0x4`	toArray() to convert to a QJsonArray
`QJsonValue::Object`	`0x5`	toObject() to convert to a QJsonObject
`QJsonValue::Undefined`	`0x80`	Usually the result of an error when trying to read an out of bounds value in an array or a non existent key in an object

Constructor & Destructor Documentation

QJsonValue::QJsonValue ( Type type = Null )

Creates a QJsonValue of the given type. The default is to create a null value.

QJsonValue::QJsonValue ( bool b )

Creates a value of type bool with value b.

QJsonValue::QJsonValue ( double n )

Creates a value of type double with value n.

QJsonValue::QJsonValue ( int n )

Creates a value of type double with value n.

QJsonValue::QJsonValue ( qint64 n )

Creates a value of type double, with value n.

Note: The integer limits for IEEE 754 double precision data is 2^53 (-9007199254740992 to +9007199254740992). If you pass in a value outside this range expect a loss of precision to occur.

QJsonValue::QJsonValue ( QString str )

Creates a value of type string with value str.

QJsonValue::QJsonValue ( QJsonArray array )

Creates a value of type array with value array.

QJsonValue::QJsonValue ( QJsonObject object )

Creates a value of type object with value object.

QJsonValue::QJsonValue ( const QJsonValue & other )

Creates a copy of other.

QJsonValue::~QJsonValue ( )

Destroys the value.

Method Documentation

QJsonValue QJsonValue::fromVariant ( const QVariant & variant )

static

Converts variant to a QJsonValue and returns the converted value. For all other QVariant types which are not shown in the table below, a conversion to a QString will be attempted. If the returned string is empty a null QJsonValue will be returned.

Source Type	Destination Type
QVariant::Bool	QJsonValue::Bool
QVariant::Int QVariant::UInt QVariant::LongLong QVariant::ULongLong QVariant::Double QVariant::Float	QJsonValue::Double
QVariant::String	QJsonValue::String
QVariant::StringList QVariant::List	QJsonValue::Array
QVariant::Hash QVariant::Map	QJsonValue::Object

See also: toVariant()

bool QJsonValue::isArray ( ) const

inline

Returns true if the value contains an array.

See also: toArray()

bool QJsonValue::isBool ( ) const

inline

Returns true if the value contains a boolean.

See also: toBool()

bool QJsonValue::isDouble ( ) const

inline

Returns true if the value contains a double.

See also: toDouble()

bool QJsonValue::isNull ( ) const

inline

Returns true if the value is null.

bool QJsonValue::isObject ( ) const

inline

Returns true if the value contains an object.

See also: toObject()

bool QJsonValue::isString ( ) const

inline

Returns true if the value contains a string.

See also: toString()

bool QJsonValue::isUndefined ( ) const

inline

Returns true if the value is undefined. This can happen in certain error cases, for example accessing a non existing key in a QJsonObject.

bool QJsonValue::operator!= ( const QJsonValue & other ) const

Returns true if the value is not equal to other.

QJsonValue & QJsonValue::operator= ( const QJsonValue & other )

Copy assigns from other and returns a reference to this object.

bool QJsonValue::operator== ( const QJsonValue & other ) const

Returns true if the value is equal to other.

QJsonArray QJsonValue::toArray ( ) const

Returns the value as a QJsonArray. If the type() is not an array an empty array will be returned.

QJsonArray QJsonValue::toArray ( const QJsonArray & defaultValue ) const

Returns the value as a QJsonArray. If the type() is not an array the defaultValue will be returned.

bool QJsonValue::toBool ( bool defaultValue = false ) const

Returns the value as a bool. If the type() is not a bool the defaultValue will be returned.

double QJsonValue::toDouble ( double defaultValue = 0 ) const

Returns the value as a double. If the type() is not a double the defaultValue will be returned.

int QJsonValue::toInt ( int defaultValue = 0 ) const

Returns the value as an int. If the type() is not a double the defaultValue will be returned.

QJsonObject QJsonValue::toObject ( ) const

Returns the value as an object. If the type() is not an object an empty object will be returned.

QJsonObject QJsonValue::toObject ( const QJsonObject & defaultValue ) const

Returns the value as an object. If the type() is not an object the defaultValue will be returned.

QString QJsonValue::toString ( const QString & defaultValue = QString() ) const

Returns the value as a string. If the type() is not a string the defaultValue will be returned.

QVariant QJsonValue::toVariant ( ) const

Converts the given value to a QVariant. The QJsonValue will be converted to a QVariant of the corresponding type.

JSON Data Type	Description
`QJsonValue::Null`	Empty QVariant
`QJsonValue::Undefined`	Empty QVariant
`QJsonValue::Bool`	QVariant::Bool
`QJsonValue::Double`	QVariant::Double
`QJsonValue::String`	QString
`QJsonValue::Array`	QVariantList
`QJsonValue::Object`	QVariantMap

See also: fromVariant()

Type QJsonValue::type ( ) const

Returns the type of the value.

See also: QJsonValue::Type

Public Types

Public Methods

Static Public Methods

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Method Documentation