The QJsonObject::const_iterator 类提供 STL 样式 const 迭代器为 QJsonObject . 更多...
| 头： | #include <const_iterator> |
| qmake: | QT += core |
| Since: | Qt 5.0 |
| typedef | iterator_category |
| const_iterator () | |
| const_iterator (const iterator & other ) | |
| QString | key () const |
| QJsonValue | value () const |
| bool | operator!= (const const_iterator & other ) const |
| bool | operator!= (const iterator & other ) const |
| QJsonValue | operator* () const |
| const_iterator | operator+ (int j ) const |
| const_iterator & | operator++ () |
| const_iterator | operator++ ( int ) |
| const_iterator & | operator+= (int j ) |
| const_iterator | operator- (int j ) const |
| const_iterator & | operator-- () |
| const_iterator | operator-- ( int ) |
| const_iterator & | operator-= (int j ) |
| QJsonValue * | operator-> () const |
| bool | operator== (const const_iterator & other ) const |
| bool | operator== (const iterator & other ) const |
The QJsonObject::const_iterator 类提供 STL 样式 const 迭代器为 QJsonObject .
QJsonObject::const_iterator allows you to iterate over a QJsonObject . If you want to modify the QJsonObject as you iterate over it, you must use QJsonObject::iterator instead. It is generally good practice to use QJsonObject::const_iterator on a non-const QJsonObject as well, unless you need to change the QJsonObject through the iterator. Const iterators are slightly faster and improve code readability.
默认 QJsonObject::const_iterator constructor creates an uninitialized iterator. You must initialize it using a QJsonObject function like QJsonObject::constBegin (), QJsonObject::constEnd ()，或 QJsonObject::find () before you can start iterating.
Multiple iterators can be used on the same object. Existing iterators will however become dangling if the object gets modified.
另请参阅 QJsonObject::iterator , 在 Qt 中支持 JSON ，和 JSON 保存游戏范例 .
同义词 std::random_access_iterator_tag indicating this iterator is a random-access iterator.
注意： In Qt versions before 5.6, this was set by mistake to std::bidirectional_iterator_tag .
返回
true
if
other
指向与此迭代器不同的项；否则返回
false
.
另请参阅 operator== ().
返回
true
if
other
points to the same item as this iterator; otherwise returns
false
.
另请参阅 operator!= ().
Constructs an uninitialized iterator.
Functions like key (), value (), and operator++() must not be called on an uninitialized iterator. Use operator=() to assign a value to it before using it.
另请参阅 QJsonObject::constBegin () 和 QJsonObject::constEnd ().
构造副本为 other .
Returns the current item's key.
另请参阅 value ().
Returns the current item's value.
Returns the current item's value.
如同 value ().
另请参阅 key ().
Returns an iterator to the item at j positions forward from this iterator. If j is negative, the iterator goes backward.
This operation can be slow for large j 值。
另请参阅 operator- ().
The prefix ++ operator,
++i
, advances the iterator to the next item in the object and returns an iterator to the new current item.
Calling this function on QJsonObject::end () leads to undefined results.
另请参阅 operator-- ().
这是重载函数。
The postfix ++ operator,
i++
, advances the iterator to the next item in the object and returns an iterator to the previously current item.
Advances the iterator by j items. If j is negative, the iterator goes backward.
This operation can be slow for large j 值。
另请参阅 operator-= () 和 operator+ ().
Returns an iterator to the item at j positions backward from this iterator. If j is negative, the iterator goes forward.
This operation can be slow for large j 值。
另请参阅 operator+ ().
The prefix -- operator,
--i
, makes the preceding item current and returns an iterator pointing to the new current item.
Calling this function on QJsonObject::begin () leads to undefined results.
另请参阅 operator++ ().
这是重载函数。
The postfix -- operator,
i--
, makes the preceding item current and returns an iterator pointing to the previously current item.
Makes the iterator go back by j items. If j is negative, the iterator goes forward.
This operation can be slow for large j 值。
另请参阅 operator+= () 和 operator- ().
Returns a pointer to the current item.
