QJsonObject 类

QJsonObject class encapsulates a JSON object. 更多...

头: #include <QJsonObject>
qmake: QT += core
Since: Qt 5.0

注意: 此类的所有函数 可重入 .

公共类型

class const_iterator
class iterator
typedef ConstIterator
typedef Iterator
typedef key_type
typedef mapped_type
typedef size_type

公共函数

QJsonObject ()
QJsonObject (std::initializer_list<QPair<QString, QJsonValue> > args )
QJsonObject (const QJsonObject & other )
~QJsonObject ()
iterator begin ()
const_iterator begin () const
const_iterator constBegin () const
const_iterator constEnd () const
const_iterator constFind (const QString & key ) const
const_iterator constFind (QLatin1String key ) const
bool contains (const QString & key ) const
bool contains (QLatin1String key ) const
int count () const
bool empty () const
iterator end ()
const_iterator end () const
iterator erase (iterator it )
iterator find (const QString & key )
iterator find (QLatin1String key )
const_iterator find (const QString & key ) const
const_iterator find (QLatin1String key ) const
iterator insert (const QString & key , const QJsonValue & value )
bool isEmpty () const
QStringList keys () const
int length () const
void remove (const QString & key )
int size () const
QJsonValue take (const QString & key )
QVariantHash toVariantHash () const
QVariantMap toVariantMap () const
QJsonValue value (const QString & key ) const
QJsonValue value (QLatin1String key ) const
bool operator!= (const QJsonObject & other ) const
QJsonObject & operator= (const QJsonObject & other )
bool operator== (const QJsonObject & other ) const
QJsonValue operator[] (const QString & key ) const
QJsonValue operator[] (QLatin1String key ) const
QJsonValueRef operator[] (const QString & key )
QJsonValueRef operator[] (QLatin1String key )

静态公共成员

QJsonObject fromVariantHash (const QVariantHash & hash )
QJsonObject fromVariantMap (const QVariantMap & map )

详细描述

QJsonObject class encapsulates a JSON object.

A JSON object is a list of key value pairs, where the keys are unique strings and the values are represented by a QJsonValue .

A QJsonObject can be converted to and from a QVariantMap . You can query the number of (key, value) pairs with size (), insert (),和 remove () entries from it and iterate over its content using the standard C++ iterator pattern.

QJsonObject is an implicitly shared class, and shares the data with the document it has been created from as long as it is not being modified.

You can convert the object to and from text based JSON through QJsonDocument .

另请参阅 在 Qt 中支持 JSON and JSON 保存游戏范例 .

成员类型文档编制

typedef QJsonObject:: ConstIterator

Qt 样式同义词 QJsonObject::const_iterator .

typedef QJsonObject:: Iterator

Qt 样式同义词 QJsonObject::iterator .

typedef QJsonObject:: key_type

Typedef 为 QString . Provided for STL compatibility.

typedef QJsonObject:: mapped_type

Typedef 为 QJsonValue . Provided for STL compatibility.

typedef QJsonObject:: size_type

Typedef for int. Provided for STL compatibility.

成员函数文档编制

QJsonObject:: QJsonObject ()

构造空的 JSON 对象。

另请参阅 isEmpty ().

QJsonObject:: QJsonObject ( std::initializer_list < QPair < QString , QJsonValue > > args )

构造 QJsonObject instance initialized from args initialization list. For example:

QJsonObject object
{
    {"property1", 1},
    {"property2", 2}
};
					

该函数在 Qt 5.4 引入。

QJsonObject:: QJsonObject (const QJsonObject & other )

Creates a copy of other .

由于 QJsonObject is implicitly shared, the copy is shallow as long as the object does not get modified.

QJsonObject:: ~QJsonObject ()

销毁对象。

iterator QJsonObject:: begin ()

返回 STL 样式迭代器 pointing to the first item in the object.

另请参阅 constBegin () 和 end ().

const_iterator QJsonObject:: begin () const

这是重载函数。

const_iterator QJsonObject:: constBegin () const

返回常量 STL 样式迭代器 pointing to the first item in the object.

另请参阅 begin () 和 constEnd ().

const_iterator QJsonObject:: constEnd () const

返回常量 STL 样式迭代器 pointing to the imaginary item after the last item in the object.

另请参阅 constBegin () 和 end ().

const_iterator QJsonObject:: constFind (const QString & key ) const

Returns a const iterator pointing to the item with key key in the map.

If the map contains no item with key key , the function returns constEnd ().

const_iterator QJsonObject:: constFind ( QLatin1String key ) const

这是重载函数。

该函数在 Qt 5.7 引入。

bool QJsonObject:: contains (const QString & key ) const

返回 true if the object contains key key .

另请参阅 insert (), remove (),和 take ().

bool QJsonObject:: contains ( QLatin1String key ) const

这是重载函数。

该函数在 Qt 5.7 引入。

int QJsonObject:: count () const

这是重载函数。

如同 size ().

bool QJsonObject:: empty () const

此函数是为兼容 STL 而提供的。它相当于 isEmpty (), returning true if the object is empty; otherwise returning false .

iterator QJsonObject:: end ()

返回 STL 样式迭代器 pointing to the imaginary item after the last item in the object.

另请参阅 begin () 和 constEnd ().

const_iterator QJsonObject:: end () const

这是重载函数。

iterator QJsonObject:: erase ( iterator it )

Removes the (key, value) pair pointed to by the iterator it from the map, and returns an iterator to the next item in the map.

另请参阅 remove ().

iterator QJsonObject:: find (const QString & key )

Returns an iterator pointing to the item with key key in the map.

If the map contains no item with key key , the function returns end ().

iterator QJsonObject:: find ( QLatin1String key )

这是重载函数。

该函数在 Qt 5.7 引入。

const_iterator QJsonObject:: find (const QString & key ) const

这是重载函数。

const_iterator QJsonObject:: find ( QLatin1String key ) const

这是重载函数。

该函数在 Qt 5.7 引入。

[static] QJsonObject QJsonObject:: fromVariantHash (const QVariantHash & hash )

Converts the variant hash hash QJsonObject .

The keys in hash will be used as the keys in the JSON object, and the QVariant values will be converted to JSON values.

该函数在 Qt 5.5 引入。

另请参阅 fromVariantMap (), toVariantHash (),和 QJsonValue::fromVariant ().

[static] QJsonObject QJsonObject:: fromVariantMap (const QVariantMap & map )

Converts the variant map map QJsonObject .

The keys in map will be used as the keys in the JSON object, and the QVariant values will be converted to JSON values.

另请参阅 fromVariantHash (), toVariantMap (),和 QJsonValue::fromVariant ().

iterator QJsonObject:: insert (const QString & key , const QJsonValue & value )

Inserts a new item with the key key and a value of value .

If there is already an item with the key key , then that item's value is replaced with value .

Returns an iterator pointing to the inserted item.

If the value is QJsonValue::Undefined , it will cause the key to get removed from the object. The returned iterator will then point to end ().

另请参阅 remove (), take (), QJsonObject::iterator ,和 end ().

bool QJsonObject:: isEmpty () const

返回 true if the object is empty. This is the same as size () == 0.

另请参阅 size ().

QStringList QJsonObject:: keys () const

返回在此对象中的所有键列表。

The list is sorted lexographically.

int QJsonObject:: length () const

这是重载函数。

如同 size ().

void QJsonObject:: remove (const QString & key )

移除 key 从对象。

另请参阅 insert () 和 take ().

int QJsonObject:: size () const

Returns the number of (key, value) pairs stored in the object.

QJsonValue QJsonObject:: take (const QString & key )

移除 key 从对象。

返回 QJsonValue containing the value referenced by key 。若 key was not contained in the object, the returned QJsonValue is QJsonValue::Undefined .

另请参阅 insert (), remove (),和 QJsonValue .

QVariantHash QJsonObject:: toVariantHash () const

把此对象转换成 QVariantHash .

返回创建的哈希。

该函数在 Qt 5.5 引入。

另请参阅 toVariantMap ().

QVariantMap QJsonObject:: toVariantMap () const

把此对象转换成 QVariantMap .

返回创建的映射。

另请参阅 toVariantHash ().

QJsonValue QJsonObject:: value (const QString & key ) const

返回 QJsonValue 表示值为键 key .

返回的 QJsonValue is QJsonValue::Undefined 若键不存在。

另请参阅 QJsonValue and QJsonValue::isUndefined ().

QJsonValue QJsonObject:: value ( QLatin1String key ) const

这是重载函数。

该函数在 Qt 5.7 引入。

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

返回 true if other is not equal to this object.

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

赋值 other 到此对象。

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

返回 true if other is equal to this object.

QJsonValue QJsonObject:: operator[] (const QString & key ) const

返回 QJsonValue 表示值为键 key .

This does the same as value ().

返回的 QJsonValue is QJsonValue::Undefined 若键不存在。

另请参阅 value (), QJsonValue ,和 QJsonValue::isUndefined ().

QJsonValue QJsonObject:: operator[] ( QLatin1String key ) const

这是重载函数。

该函数在 Qt 5.7 引入。

QJsonValueRef QJsonObject:: operator[] (const QString & key )

Returns a reference to the value for key .

The return value is of type QJsonValueRef , a helper class for QJsonArray and QJsonObject . When you get an object of type QJsonValueRef , you can use it as if it were a reference to a QJsonValue . If you assign to it, the assignment will apply to the element in the QJsonArray or QJsonObject from which you got the reference.

另请参阅 value ().

QJsonValueRef QJsonObject:: operator[] ( QLatin1String key )

这是重载函数。

该函数在 Qt 5.7 引入。