×

Discussion Board

Results 1 to 3 of 3
  1. #1
    Registered User
    Join Date
    Nov 2010
    Posts
    17

    what's "a null update"?

    in the help file:

    QGeoPositionInfo QGeoPositionInfoSource::lastKnownPosition ( bool fromSatellitePositioningMethodsOnly = false ) const [pure virtual]

    Returns an update containing the last known position, or a null update if none is available.

    If fromSatellitePositioningMethodsOnly is true, this returns the last known position received from a satellite positioning method; if none is available, a null update is returned.



    my question is how to determine the return value is availbale. what's "a null update"? sample code is prefered.

    Thank you!

  2. #2
    Regular Contributor
    Join Date
    Oct 2008
    Location
    Oslo, Norway
    Posts
    329

    Re: what's "a null update"?

    Hi,

    If no last known position is available, it'll return an instance of QGeoPositionInfo that was created using a default constructor, i.e. with none of the attributes set. In this case, QGeoPositionInfo::isValid() will return false.

  3. #3
    Registered User
    Join Date
    Nov 2010
    Posts
    17

    Re: what's "a null update"?

    I see.
    Thank you!


    I have another question, please refer to the position getted by QGeoPositionInfoSource not accurate .

Similar Threads

  1. System.getProperty("microedition.platform") returns null
    By mikael_rinnetmaki in forum Mobile Java General
    Replies: 9
    Last Post: 2012-02-13, 20:09
  2. FileConnection reads file and returns "Null" Exception
    By thechameleon in forum Mobile Java General
    Replies: 6
    Last Post: 2009-08-15, 18:46
  3. "-addjarsig failed: java.security.InvalidKeyException: Key must not be null"
    By eesbee in forum Mobile Java Networking & Messaging & Security
    Replies: 1
    Last Post: 2009-07-30, 13:51
  4. Replies: 4
    Last Post: 2008-05-20, 19:07
  5. Exception with ISO14443Connection Connector.open and message "null"
    By smischi in forum Near Field Communication
    Replies: 2
    Last Post: 2008-01-21, 16:31

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
×