How long is your list? And how often does the list items themselves change?
Instead of reformatting the same numbers again and again every time the list is repainted, how about formatting them once into a list of Strings, and reuse these strings? On Tue, Apr 14, 2009 at 2:29 PM, DavidG <[email protected]> wrote: > > That's right, with the code above, it still GCs about 13000 every 2 > seconds (as long as I'm scrolling the list quickly back and forth). If > I comment out the formatter line (price = mFormatter.format("%.2f", > args).toString();) it doesn't do the GCs anymore, but I of course lose > my formatting. > > On Apr 14, 10:28 am, Marco Nelissen <[email protected]> wrote: > > When you say that it hasn't improved yourgarbagecollection problem, > > do you mean that it still GCs 13000 objects every 2 seconds? > > > > On Mon, Apr 13, 2009 at 10:42 PM, DavidG <[email protected]> wrote: > > > > > Thanks for the feedback.. Now I'm trying to use StringBuilder and > > > Formatter, but I just can't get it to stop doing thegarbage > > > collection. I'm not sure how to go about reusing the Formatter. At > > > first, I just tried creating a public static Formatter member variable > > > and using it directly: > > > > > public Formatter mFormatter = new Formatter(); > > > (then later within setViewValue()... ) > > > mFormatter.format("%.2f",pricef).toString(); > > > > > Unfortunately the formatter seemed to keep "building" onto itself, > > > making each item in the list return a longer and longer string as I > > > scrolled. > > > > > Then I looked into the Android source code and found an example that I > > > tried to mimick. While it gives me the output I expect, it hasn't > > > improved mygarbagecollection problem. I'm just going to post the > > > majority of my ViewBinder class, can someone point out where I'm going > > > wrong? > > > > > <START CODE> > > > import java.util.Formatter; > > > import android.database.Cursor; > > > import android.graphics.Color; > > > import android.graphics.Paint; > > > import android.view.View; > > > import android.widget.ImageView; > > > import android.widget.SimpleCursorAdapter; > > > import android.widget.TextView; > > > > > public class ItemBinder implements SimpleCursorAdapter.ViewBinder { > > > > > public static final StringBuilder mBuilder = new > StringBuilder(); > > > public static final Formatter mFormatter = new > Formatter(mBuilder); > > > public static final Object[] mArgs = new Object[1]; > > > > > public boolean setViewValue(View view, Cursor cursor, int > > > columnIndex) { > > > switch(view.getId()) { > > > case R.id.price: > > > // Format the price nicely > > > String price = cursor.getString(columnIndex); > > > final float pricef = Float.parseFloat(price); > > > Object[] args = mArgs; > > > args[0] = pricef; > > > mBuilder.setLength(0); > > > price = mFormatter.format("%.2f", > args).toString(); > > > ((TextView)view).setText(price); > > > return true; > > > } > > > return false; > > > } > > > } > > > <END CODE> > > > > > On Apr 13, 10:40 pm, Marco Nelissen <[email protected]> wrote: > > >> Don't use String.format(). It creates all kinds of temporary objects > > >> every time you call it. > > >> Instead, create a single StringBuilder and Formatter, and then reuse > > >> those every time you need to format a string. > > > > >> On Mon, Apr 13, 2009 at 7:37 PM, DavidG <[email protected]> wrote: > > > > >> > In my ListView, there'sonelineof code in my ViewBinder that causes > > >> > lots ofgarbagecollection as I scroll through the list, about every > > >> > two seconds... > > > > >> > D/dalvikvm(16312): GC freed 13171 objects / 659576 bytes in 162ms > > >> > D/dalvikvm(16312): GC freed 13122 objects / 654128 bytes in 129ms > > >> > D/dalvikvm(16312): GC freed 13134 objects / 655416 bytes in 142ms > > >> > D/dalvikvm(16312): GC freed 13129 objects / 654840 bytes in 129ms > > >> > D/dalvikvm(16312): GC freed 13149 objects / 655000 bytes in 110ms > > >> > D/dalvikvm(16312): GC freed 13150 objects / 655720 bytes in 127ms > > >> > D/dalvikvm(16312): GC freed 13075 objects / 652256 bytes in 111ms > > >> > D/dalvikvm(16312): GC freed 13232 objects / 659040 bytes in 136ms > > >> > D/dalvikvm(16312): GC freed 13106 objects / 653920 bytes in 110ms > > >> > D/dalvikvm(16312): GC freed 13155 objects / 655152 bytes in 110ms > > > > >> > The offending code is here, which formats a price for each item in > the > > >> > list: > > > > >> > String price = cursor.getString(columnIndex); > > >> > final float pricef = Float.parseFloat(price); > > >> > price = new StringBuffer("$").append(String.format("%. > > >> > 2f",pricef)).toString(); > > >> > ((TextView)view).setText(price); > > > > >> > If I comment out thelinewith String.format, thegarbagecollection > > >> > goes away. So what's the "right" way to do this to avoid > allocations? > > >> > That database field holds an unformatted text string which I'm > trying > > >> > to format into proper currency format (example: format "1.5" to > > >> > "$1.50") > > > > >> > Any pointers on how to improve this? > > > > > > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
