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Q3PtrDictIterator Class Reference
[Qt3Support module]

The Q3PtrDictIterator class provides an iterator for Q3PtrDict collections. More...

 #include <Q3PtrDictIterator>

This class is part of the Qt 3 support library. It is provided to keep old source code working. We strongly advise against using it in new code. See Porting to Qt 4 for more information.


Public Functions

Q3PtrDictIterator ( const Q3PtrDict<type> & dict )
~Q3PtrDictIterator ()
uint count () const
type * current () const
void * currentKey () const
bool isEmpty () const
type * toFirst ()
operator type * () const
type * operator() ()
type * operator++ ()
type * operator+= ( uint jump )

Detailed Description

The Q3PtrDictIterator class provides an iterator for Q3PtrDict collections.

Q3PtrDictIterator is implemented as a template class. Define a template instance Q3PtrDictIterator<X> to create a dictionary iterator that operates on Q3PtrDict<X> (dictionary of X*).

Example:

 Q3PtrDict<char> fields;

 QLineEdit *le1 = new QLineEdit( this );
 le1->setText( "Simpson" );
 QLineEdit *le2 = new QLineEdit( this );
 le2->setText( "Homer" );
 QLineEdit *le3 = new QLineEdit( this );
 le3->setText( "45" );

 fields.insert( le1, "Surname" );
 fields.insert( le2, "Forename" );
 fields.insert( le3, "Age" );

 Q3PtrDictIterator<char> it( fields );
 for( ; it.current(); ++it ) {
     QLineEdit *le = (QLineEdit)it.currentKey();
     cout << it.current() << ": " << le->text() << endl;
 }
 cout << endl;

 // Output (random order):
 //  Forename: Homer
 //  Age: 45
 //  Surname: Simpson

In the example we insert some line edits into a dictionary, associating a string with each. We then iterate over the dictionary printing the associated strings.

Multiple iterators may independently traverse the same dictionary. A Q3PtrDict knows about all the iterators that are operating on the dictionary. When an item is removed from the dictionary, Q3PtrDict updates all iterators that refer the removed item to point to the next item in the traversing order.

See also Q3PtrDict.


Member Function Documentation

Q3PtrDictIterator::Q3PtrDictIterator ( const Q3PtrDict<type> & dict )

Constructs an iterator for dict. The current iterator item is set to point on the first item in the dict.

Q3PtrDictIterator::~Q3PtrDictIterator ()

Destroys the iterator.

uint Q3PtrDictIterator::count () const

Returns the number of items in the dictionary this iterator operates on.

See also isEmpty().

type * Q3PtrDictIterator::current () const

Returns a pointer to the current iterator item's value.

void * Q3PtrDictIterator::currentKey () const

Returns the current iterator item's key.

bool Q3PtrDictIterator::isEmpty () const

Returns TRUE if the dictionary is empty; otherwise returns FALSE.

See also count().

type * Q3PtrDictIterator::toFirst ()

Sets the current iterator item to point to the first item in the dictionary and returns a pointer to the item. If the dictionary is empty, it sets the current item to 0 and returns 0.

Q3PtrDictIterator::operator type * () const

Cast operator. Returns a pointer to the current iterator item. Same as current().

type * Q3PtrDictIterator::operator() ()

Makes the succeeding item current and returns the original current item.

If the current iterator item was the last item in the dictionary or if it was 0, 0 is returned.

type * Q3PtrDictIterator::operator++ ()

Prefix ++ makes the succeeding item current and returns the new current item.

If the current iterator item was the last item in the dictionary or if it was 0, 0 is returned.

type * Q3PtrDictIterator::operator+= ( uint jump )

Sets the current item to the item jump positions after the current item and returns a pointer to that item.

If that item is beyond the last item or if the dictionary is empty, it sets the current item to 0 and returns 0.


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Qt 4.6.3