Oh having the debugger attached always have a significant impact on performance.
Always remember, once you say the word "performance" there should be a real device involved that is driving the work. On Wed, Jul 22, 2009 at 12:57 PM, gnugu <[email protected]> wrote: > > > Just creating 1000 objects isn't going to take 45 seconds, it sounds like > I was running it in the emulator with the debugger attached. I'll > check logs and try the profiler. > > Thanks. > > On Jul 22, 12:02 pm, Dianne Hackborn <[email protected]> wrote: > > 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. > > > -- 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 -~----------~----~----~----~------~----~------~--~---
