Just creating 1000 objects isn't going to take 45 seconds, it sounds like you have something really bad going on somewhere. With it taking that amount of time, you will probably quickly see some serious hot spots if you run the profiler.
Also if you are seeing log messages about the GC running during that time, this means that something in your code is creating tons and tons of temporary objects. Again the profiler should help a lot in tracking this down. On Wed, Jul 22, 2009 at 11:39 AM, gnugu <[email protected]> wrote: > > Dianne, > > It is not reading and writing that's slow. > > I have a class that has Notes field (ArrayList<Note>). I wrote my test > to create 1000 note objects and add it took 45 seconds. > Because I can't get XML string out of DOM Document I can't use the > Document as my storage for notes which leaves me with creating all > these objects as I read the XML. > > It would be ideal for me to use MySQL to store the notes but then I > would want to encrypt the table as a whole rather then individual > records. > > My own binary format might work if I create my own data reader that > would work on my binary data. That's a lot of work. > > Hmm, I wonder if I could simply encrypt the database file. But then > how do I feed it to DatabaseHelper? > > On Jul 22, 11:26 am, Dianne Hackborn <[email protected]> wrote: > > Which part is slow, reading or writing? If it is writing, just stay the > > heck away from the standard XML writers, they are horrendous. There is a > > FastXmlSerializer with limited functionality that you could copy out of > the > > source code for your own use: > > > > http://android.git.kernel.org/?p=platform/frameworks/base.git;a=blob;... > > > > That said, XML is just pretty intrinsically inefficient to read and > write. > > I have been yelled at more than once about using it at all. :) If the > > amount of data you are storing is relatively large, you may want to just > use > > your own binary format. Yes, this does require a lot more work to deal > with > > compatibility as the format changes and such, but often that is worth it, > > > > > > > > On Wed, Jul 22, 2009 at 9:23 AM, gnugu <[email protected]> wrote: > > > > > Hi, > > > I'm working on an application where I want to save bunch of > > > information in the XML file. I am not using MySQL because I want all > > > the info to be encrypted and in one place. I don't know how this could > > > be done in the data base. > > > > > I was thinking that I would use DOM Document for my data adapter to > > > bind with ListView. But I found out that there is no way of getting > > > the XML out of DOM Document to save it to the file! > > > > > So now I use SAX to read XML and create bunch of objects one for each > > > piece of data in memory. > > > > > The SDK Guide in Designing for Performance says to avoid creating > > > objects (http://developer.android.com/guide/practices/design/ > > > performance.html#object_creation< > http://developer.android.com/guide/practices/design/%0Aperformance.ht...> > > > ). > > > > > I understand and agree and even proved that the performance sucks if I > > > do it the way I described above. > > > > > What other choice there might be? Anybody has any suggestions how I > > > could save bunch of notes and have them all encrypted with ONE > > > password as a key base? I know I could use that one key to encrypt > > > every database row, but then changing the password would be difficult. > > > > > Any suggestions? > > > > > Thanks. > > > > -- > > Dianne Hackborn > > Android framework engineer > > [email protected] > > > > Note: please don't send private questions to me, as I don't have time to > > provide private support, and so won't reply to such e-mails. All such > > questions should be posted on public forums, where I and others can see > and > > answer them. > > > -- Dianne Hackborn Android framework engineer [email protected] Note: please don't send private questions to me, as I don't have time to provide private support, and so won't reply to such e-mails. All such questions should be posted on public forums, where I and others can see and answer them. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~----------~----~----~----~------~----~------~--~---
