[android-developers] Need help using hat to track down memory usage
Hello, While perusing the source code, came across a shell function that envsetup.sh defines called runhat. Judging by the parameters, etc., to this function, it allows one to get a heap-dump for a given application. This dump can then be analyzed by the tools hat and jhat. Has anyone had any luck running these tools? I tried earlier today and consistently get an error message Started HTTP server on port 7000 Reading from /tmp/t.hat... java.io.IOException: Version string not recognized at byte 17 at hat.parser.HprofReader.readVersionHeader(HprofReader.java:325) at hat.parser.HprofReader.read(HprofReader.java:169) at hat.parser.Reader.readFile(Reader.java:90) at hat.Main.main(Main.java:149) I have tried jhat (built into Java SE 6.0) as well as hat (downloaded from https://hat.dev.java.net/). Both versions get the same error. Can anyone help? Thanks, DS. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com 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 -~--~~~~--~~--~--~---
[android-developers] Re: ListView - If you have a item that can focus you can select the Item
Hi Romain Guy, What is the attribute you mention below that makes ListView items selectable or focusable? i.e., how/what does one change to make ListView items focusable by default (and not selectable)? Thanks, Nitin. On Aug 27, 2008, at 1:28 PM, Romain Guy wrote: So, in conclusion, I can have a focusable item or a focusable child into the item but not both. No, items in a ListView are not focusable by default, they are selectable. So an item can be focusable (it gets focus or one of its children gets focus) OR selectable, but not both. You can make the item and its children focusable if you want. But keyboard focus navigation might not work properly in that case (overlapping focusable items are not handled very well for now.) That means, for example, that if I want to have a list of songs, where if I select one I play it, and each one have a button to add to one playlist is not possible? And another quick question, Can I have a SurfaceView able to display videos and photos?, lets say, for example, that I want to put a loading image while downloading the video, is that possible? (using MediaPlayer yo play the video). Thanks. -- Romain Guy www.curious-creature.org --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com 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 -~--~~~~--~~--~--~---
[android-developers] ViewGroup and LayoutAnimation question
Hello, A question on how a Layout animation works with a ViewGroup object such as a ListView. As shown in many ApiDemo examples, when the screen is first rendered/layed-out, the animation sequence runs nicely. How can one get the Layout animation to re-play on demand. I have tried two different mechanisms LayoutAnimationController lac = vg.getLayoutAnimation (); lac.start(); as well as a simple vg.requestLayout(); thinking that the latter will simply cause the whole ViewGroup to re- render and therefore replay the animation. Neither of these seems to work. Any ideas? Thanks, DS. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com 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 -~--~~~~--~~--~--~---
[android-developers] Programmatic scrolling of a ListView?
Hello, When we use setSelectionFromTop(), the list adjusts itself so that the selection is positioned some y pixels from the top. However, this happens in a somewhat 'sudden' manner. Is it possible to make this animated where the list appears to smoothly scroll and then settles in its final position? Thanks, DS. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com 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 -~--~~~~--~~--~--~---
[android-developers] WebView unable to display www.google.com?
Hi,
Here is a simple test activity that is unable to show www.google.com.
However, www.yahoo.com shows properly. It is strange that the same
URL, http://www.google.com/; renders just fine in the web browser
application built into the SDK.
Any ideas?
Thanks,
DS.
public class WebViewTestActivity extends Activity {
/* (non-Javadoc)
* @see android.app.Activity#onCreate(android.os.Bundle)
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
WebView wv = new WebView(this);
wv.loadUrl(http://www.google.com;);
setContentView (wv);
}
}
-
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[android-developers] Re: WebView unable to display www.google.com?
As always, Mark Murphy to the rescue. Thanks a bunch, Mark. Regards, DS. PS: Any thoughts on another problem I posted earlier about focus issues when a WebView partially obscures a ListView? - DS. On Sep 22, 2008, at 3:55 PM, Mark Murphy wrote: Here is a simple test activity that is unable to show www.google.com. However, www.yahoo.com shows properly. It is strange that the same URL, http://www.google.com/; renders just fine in the web browser application built into the SDK. This baffled me for the longest time, but somebody pointed out the issue a month or two ago. The Google home page uses Javascript, and WebView does not have Javascript enabled by default. Use WebSettings to enable Javascript, and the Google home page should then work. -- Mark Murphy (a Commons Guy) http://commonsware.com _The Busy Coder's Guide to Android Development_ Version 1.2 Published! --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com 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 -~--~~~~--~~--~--~---
[android-developers] Bug in focus handling between WebView and ListView
Hello folks, There appears to be a bug in focus handling when a WebView is partially overlapping a ListView. I am able to reproduce this problem via a simple change to one of the ApiDemos example. If you change the file ApiDemos/res/layout/linear_layout_9.xml to be as given below, and run the demo Views/Layouts/LinearLayout/9.Layout Weight, this change causes a WebView to be overlaid on top of the list such that the list is partially obscured. Now, any mouse motions on top of the WebView seem to make their way to the ListView. The embedded WebView object never gets focus. for example, one can hold the mouse on top of the WebView and cause the ListView (which is obscured) to respond to scrolling action. If you replace the WebView with a TextView instead, then the TextView intercepts all mouse events as expected. Any thoughts on where this bug lies and potential workarounds will be greatly appreciated. Thanks, DS. ---linear_layout_9.xml--- ?xml version=1.0 encoding=utf-8? !-- Demonstrates a simple linear layout. The layout fills the screen, with the children stacked from the top. -- AbsoluteLayout xmlns:android=http://schemas.android.com/apk/res/android android:orientation=vertical android:layout_width=fill_parent android:layout_height=fill_parent ListView android:id=@+id/list android:layout_width=fill_parent android:layout_height=wrap_content android:layout_weight=1.0 / Button android:layout_width=fill_parent android:layout_height=wrap_content android:text=@string/linear_layout_9_button / WebView android:layout_width=fill_parent android:layout_height=fill_parent android:layout_x=500px android:layout_y=200px android:background=# android:clickable=true / /AbsoluteLayout !-- * Copyright (C) 2007 Google Inc. * * Licensed under the Apache License, Version 2.0 (the License); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an AS IS BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. -- --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com 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 -~--~~~~--~~--~--~---
[android-developers] Question about NPE in AdapterView.rememberSyncState()
Hello, Hoping for an answer from the Android team on this one. Could you please shed some light on the following NPE? ERROR/AndroidRuntime(1789): java.lang.NullPointerException ERROR/AndroidRuntime(1789): at android.widget.AdapterView.rememberSyncState(AdapterView.java:799) ERROR/AndroidRuntime(1789): at android.widget.AdapterView $MyDataSetObserver.onChanged(AdapterView.java:548) ERROR/AndroidRuntime(1789): at android .database.DataSetObservable.notifyChanged(DataSetObservable.java:29) ERROR/AndroidRuntime(1789): at android.widget.BaseAdapter.notifyDataSetChanged(BaseAdapter.java:42) It started showing up in my code rather mysteriously. Also there does not seem to be any usage pattern that atleast I can discern. Any ideas on what might be causing this? Thanks a bunch. Regards, DS. PS: This is on the M5 SDK - DS --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new Android 0.9 SDK beta! http://android-developers.blogspot.com/2008/08/announcing-beta-release-of-android-sdk.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: Is a Dialog completely modal?
Hi Hackbod, Thanks a bunch. That fixed it. The method setFlags() has a second argument to it called mask, it works when I pass it 0x and not 0. I take it that is expected. Thanks, DS. On Jul 9, 2008, at 5:18 PM, hackbod wrote: You can do this to make it non-modal for touch events: Dialog .getWindow ().setFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL); On Jul 9, 8:09 am, Disco Stu 010 [EMAIL PROTECTED] wrote: Hi, Have a question w.r.t the Dialog object. Is it at all possible to have a Dialog object overlaid on an Activity such that if a touch event is registered outside the bounds of the Dialog, then the event is sent to the View behind the Dialog. From what little experiments I have done, it appears that a Dialog is completely modal and consumes every event on the screen. There does not seem to be a way to hand the event off to other view objects. Any thoughts? Thanks, DS. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new M5 SDK! http://android-developers.blogspot.com/2008/02/android-sdk-m5-rc14-now-available.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Is a Dialog completely modal?
Hi, Have a question w.r.t the Dialog object. Is it at all possible to have a Dialog object overlaid on an Activity such that if a touch event is registered outside the bounds of the Dialog, then the event is sent to the View behind the Dialog. From what little experiments I have done, it appears that a Dialog is completely modal and consumes every event on the screen. There does not seem to be a way to hand the event off to other view objects. Any thoughts? Thanks, DS. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new M5 SDK! http://android-developers.blogspot.com/2008/02/android-sdk-m5-rc14-now-available.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] How does deleteRow work in a Cursor object
Hello, Hope some experts can shed light on the workings of a Cursor object. Lets refer to the NotesList sample project accompanying the SDK. Here we have a ContentProvider that returns the results of a query as a Cursor object. The recipient of the Query can use this Cursor object whichever way it wants including making a deleteRow call. Now, according to the documentation, deleteRow is supposed to delete a row from the underlying datastore. How does the Cursor know what table/row the cursor correspond to? I tried to single-step through the NotesList application and the delete method belonging to the DataProvider class, NotePadProvider is not used at all. How does the Cursor end up bypassing the DataProvider responsible for the Database? Further more, the cursor can be the result of a complex join query in which case, how would anyone know which row to delete? Any insights will be greatly appreciated. Mark Murphy, any thoughts? :) Thanks, DS. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new M5 SDK! http://android-developers.blogspot.com/2008/02/android-sdk-m5-rc14-now-available.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: How does deleteRow work in a Cursor object
Hey Mark, Thanks again. I had reached the same conclusion as you that Cursor.deleteRow() should result in a DataProvider.delete with some URI. However, I dont see that happening. I added a Log.w statement to query(), insert(), delete() and update() methods of the data provider and only query() and insert() are being called. Maybe some Android team members can shed light on this? Thanks, DS. PS: BTW, I am able to single-step through the debugger on insert so atleast in this case, the debugger seems to work - NS. On Jul 8, 2008, at 3:39 PM, Mark Murphy wrote: Mark Murphy, any thoughts? :) blink, blink Thanks for the vote of confidence! Though, bear in mind, I'm not an Android team member, nor do I play one on TV. Now, according to the documentation, deleteRow is supposed to delete a row from the underlying datastore. How does the Cursor know what table/row the cursor correspond to? It's been a while since I looked at NotePad, so forgive me if I mis- speak here... NotePad uses a ContentProvider (NotePadProvider), so the Cursor you're presumably referring to is the one in the activity showing the notes (e.g., NotesList). In that case, the Cursor isn't directly accessing the database (a la SQLiteCursor), but rather wraps the Intent-laden IPC mechanism that Android has...somewhere...that bridges between the Cursor and the ContentProvider interface supported by the NotePadProvider. Content providers may not be in-process, particularly if they're supplied by some other application than your own. When you call deleteRow() on the Cursor, the Cursor does not know the table/row, as the Cursor has no idea how the ContentProvider is providing the content: SQLite? in-memory data? random-data generator? What the Cursor *does* know, though, is the Uri of the piece of content the Cursor presently points to. On a deleteRow(), that Uri eventually winds up as a parameter to the delete() method on the NotePadProvider (again, via Androidy IPC goodness). It is up to NotePadProvider to parse that Uri and determine the appropriate table/row. I tried to single-step through the NotesList application and the delete method belonging to the DataProvider class, NotePadProvider is not used at all. I find that somewhat difficult to believe. Maybe the debugger doesn't step through the Android innards as Cursor#deleteRow() goes through the IPC to get to ContentProvider#delete(). Further more, the cursor can be the result of a complex join query in which case, how would anyone know which row to delete? If you do a complex join while query()-ing content://com.google.provider.NotePad/notes, and you get back rows with IDs of 4, 8, 15, 16, 23, and 42, the Cursor turns those into Uri instances like content://com.google.provider.NotePad/notes/4 and so on. When it comes to Cursors and ContentProviders, the Uri is your friend. -- Mark Murphy (a Commons Guy) http://commonsware.com _The Busy Coder's Guide to Android Development_ -- Available Now! --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new M5 SDK! http://android-developers.blogspot.com/2008/02/android-sdk-m5-rc14-now-available.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: How does deleteRow work in a Cursor object
Hi, I see...Is this to make the behavior more consistent? If it gets deprecated, then when a Cursor is being used as a ListAdapter and an entry needs to be deleted, would we take the following steps? 1. Issue a delete() to the DataProvider with the appropriate URL and the relevant parameters. 2. Issue a Cursor.requery() to get the List to refresh itself OR 2. Reissue the query to get a new Cursor and use that to create a new ListAdapter. Thanks, DS. On Jul 8, 2008, at 7:16 PM, Romain Guy wrote: Hi, Cursor.deleteRow() will be deprecated in or removed from the next SDK. On Tue, Jul 8, 2008 at 4:10 PM, Disco Stu 010 [EMAIL PROTECTED] wrote: Hey Mark, Thanks again. I had reached the same conclusion as you that Cursor.deleteRow() should result in a DataProvider.delete with some URI. However, I dont see that happening. I added a Log.w statement to query(), insert(), delete() and update() methods of the data provider and only query() and insert() are being called. Maybe some Android team members can shed light on this? Thanks, DS. PS: BTW, I am able to single-step through the debugger on insert so atleast in this case, the debugger seems to work - NS. On Jul 8, 2008, at 3:39 PM, Mark Murphy wrote: Mark Murphy, any thoughts? :) blink, blink Thanks for the vote of confidence! Though, bear in mind, I'm not an Android team member, nor do I play one on TV. Now, according to the documentation, deleteRow is supposed to delete a row from the underlying datastore. How does the Cursor know what table/row the cursor correspond to? It's been a while since I looked at NotePad, so forgive me if I mis- speak here... NotePad uses a ContentProvider (NotePadProvider), so the Cursor you're presumably referring to is the one in the activity showing the notes (e.g., NotesList). In that case, the Cursor isn't directly accessing the database (a la SQLiteCursor), but rather wraps the Intent-laden IPC mechanism that Android has...somewhere...that bridges between the Cursor and the ContentProvider interface supported by the NotePadProvider. Content providers may not be in-process, particularly if they're supplied by some other application than your own. When you call deleteRow() on the Cursor, the Cursor does not know the table/row, as the Cursor has no idea how the ContentProvider is providing the content: SQLite? in-memory data? random-data generator? What the Cursor *does* know, though, is the Uri of the piece of content the Cursor presently points to. On a deleteRow(), that Uri eventually winds up as a parameter to the delete() method on the NotePadProvider (again, via Androidy IPC goodness). It is up to NotePadProvider to parse that Uri and determine the appropriate table/row. I tried to single-step through the NotesList application and the delete method belonging to the DataProvider class, NotePadProvider is not used at all. I find that somewhat difficult to believe. Maybe the debugger doesn't step through the Android innards as Cursor#deleteRow() goes through the IPC to get to ContentProvider#delete(). Further more, the cursor can be the result of a complex join query in which case, how would anyone know which row to delete? If you do a complex join while query()-ing content://com.google.provider.NotePad/notes, and you get back rows with IDs of 4, 8, 15, 16, 23, and 42, the Cursor turns those into Uri instances like content://com.google.provider.NotePad/notes/4 and so on. When it comes to Cursors and ContentProviders, the Uri is your friend. -- Mark Murphy (a Commons Guy) http://commonsware.com _The Busy Coder's Guide to Android Development_ -- Available Now! -- Romain Guy www.curious-creature.org --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new M5 SDK! http://android-developers.blogspot.com/2008/02/android-sdk-m5-rc14-now-available.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] How does ListActivity create multiple list items
Hello, A question for the experts on how ListActivity does its job. My understanding of the documentation is that to give a custom look to ListActivity, one needs to provide a template View (through setContentView) that contains a ListView object with the ID list. ListActivity then proceeds to use this template for all the rows it displays. My question is, how does ListActivity create multiple instances of these ListView objects? (one for each row) If using the findViewById() method, one ends up with a single View object. Is there a straightforward way to create clones of a view object? Any insights will be greatly appreciated. I would like to do something similar but with a TableLayout. Specify a template for each column in the table and be able to instantiate view objects for each table cell. Thanks, DS. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new M5 SDK! http://android-developers.blogspot.com/2008/02/android-sdk-m5-rc14-now-available.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: How does ListActivity create multiple list items
Hey Mark, Thanks for the explanation. Most helpful. I now understand that one can have any view to render a row by overriding the getView() method. My original question though still stays. If given a resource id for a view, how can one create multiple instances of that view? Can I simply call findViewById() multiple times to get different instances or do they return the same copy of the View object? Thanks, DS. PS: Looking forward to your tutorial - DS On Jul 1, 2008, at 1:30 PM, Mark Murphy wrote: My understanding of the documentation is that to give a custom look to ListActivity, one needs to provide a template View (through setContentView) that contains a ListView object with the ID list. ListActivity then proceeds to use this template for all the rows it displays. Close. There are actually two layouts you provide: one for the activity, and one for the rows. The one for the activity needs to have a ListView with the android:id of list. You connect this layout to the activity via setContentView(), like you would for any other activity. The constructor of the Adapter you use with your ListView will take the R.layout name of a second layout, this one for the rows. You are also welcome to override getView() on the Adapter, which will ignore the second layout and allow you to construct the rows by whatever means you see fit (manual constructors, ViewInflate, etc.). Later this month, I'll be writing up a tutorial on AndroidGuys about all this. -- Mark Murphy (a Commons Guy) http://commonsware.com _The Busy Coder's Guide to Android Development_ -- Available Now! --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new M5 SDK! http://android-developers.blogspot.com/2008/02/android-sdk-m5-rc14-now-available.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: How does ListActivity create multiple list items
Hi Mark, Thanks for the detailed explanation. This helps tremendously. Can you please also clarify what do you mean by use the same instance as the convertView parameter? Dont I need a new View instance for every cell being displayed? i.e., if displaying 5 TextView rows at the same time, then do we need need 5 different instances of TextView? OR is it the case that the getView() method is called only when the View is about to be drawn and therefore a single instance will suffice for displaying the whole list ? Thanks, Nitin. On Jul 1, 2008, at 3:19 PM, Mark Murphy wrote: Thanks for the explanation. Most helpful. I now understand that one can have any view to render a row by overriding the getView() method. Or by supplying your own layout XML identifier (R.layout.somethingoranother), if the rows are reasonably simple. I'm a bit of a control freak, so I prefer overriding getView(), but that's just me. My original question though still stays. If given a resource id for a view, how can one create multiple instances of that view? http://code.google.com/android/reference/android/view/ViewInflate.html ViewInflate#inflate() will create a new View based on a supplied resource ID. For example: ViewInflate inflater=getViewInflate(); // assumes you're in an Activity View view=inflater.inflate(R.layout.tourview_std, null, null); TextView distance=(TextView)view.findViewById(R.id.distance); ImageView turn=(ImageView)view.findViewById(R.id.turn); ImageView marker=(ImageView)view.findViewById(R.id.marker); TextView waypoint=(TextView)view.findViewById(R.id.waypoint); Here, I inflate R.layout.tourview_std, then use findViewById() to get at the innards. I can then set the text and images as needed. For better performance, examine the View convertView parameter passed into your getView() callback. If it's the right View to use (e.g., you're only inflating one type of row), then just reuse that instance, since it's one you inflated earlier. If it's null or the wrong view (e.g., you've got several types of rows, each with different layouts), inflate yourself a new one. The inflation process isn't the speediest, so the fewer inflates you can do, the better. Hope this helps! -- Mark Murphy (a Commons Guy) http://commonsware.com _The Busy Coder's Guide to Android Development_ -- Available Now! --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new M5 SDK! http://android-developers.blogspot.com/2008/02/android-sdk-m5-rc14-now-available.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: How does ListActivity create multiple list items
Hi Mark, I think I got it now :) Thanks a bunch for all your help. Regards. On Jul 1, 2008, at 4:19 PM, Mark Murphy wrote: Can you please also clarify what do you mean by use the same instance as the convertView parameter? Dont I need a new View instance for every cell being displayed? i.e., if displaying 5 TextView rows at the same time, then do we need need 5 different instances of TextView? OR is it the case that the getView() method is called only when the View is about to be drawn and therefore a single instance will suffice for displaying the whole list ? Ideally, Android and your activity will only create as many row Views as can be physically displayed by the ListView. Suppose you have an Adapter that wraps a set of 50 objects, but the ListView only has room to show 7 of those at a time. When your activity launches, I believe your Adapter will have getView() called 7 times with a null convertView, which you will wind up populating with the first 7 objects' data out of the 50 available objects. Then, if the user scrolls the ListView, your getView() will start being called with convertView sometimes being non-null, meaning the ListView wants to fill in an existing row's View with new data. I imagine the precise details on when getView() will be called with a possible-to-recycle convertView will vary as Android evolves. However, if you get a non-null convertView, Android is asking you to recycle that View if possible. Either return convertView (after modifying the contents to reflect the data identified by the supplied position), or return a brand-new View, as your activity sees fit. At the outset, it may be simplest to ignore convertView and just inflate new Views on each getView() call. If performance suffers, you can always try reusing convertView. -- Mark Murphy (a Commons Guy) http://commonsware.com _The Busy Coder's Guide to Android Development_ -- Available Now! --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new M5 SDK! http://android-developers.blogspot.com/2008/02/android-sdk-m5-rc14-now-available.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: Question about LayoutAnimation2.java from the ApiDemos sample project
Hi, Thanks for your response. Certainly clarifies a few things. The sample code has been immensely valuable in getting a better understanding of the Android APIs. I totally understand the 'too many things to do' problem, I have been guilty of that many times. However, I would like to respectfully submit that a very large community of developers is potentially relying on ApiDemos code to learn about Android. Well documented code should be a key element of the delivery and not simply whether the demo code works or not. There is a lot of power behind the few lines of code that is not apparent at all. Honestly, by 1.0 timeframe a large number of us might not even need to look at this code. Now is when the comments will be most helpful. Thanks again, DS. On Jun 26, 2008, at 8:55 PM, hackbod wrote: On Jun 26, 1:24 pm, Romain Guy [EMAIL PROTECTED] wrote: - Why is the ApiDemos code not commented at all? (this one is an extra credit question) Too many things to do :) And we can continue to put comments in sample code after completing the final code for 1.0, so it is pretty low in priority at this time. :) --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new M5 SDK! http://android-developers.blogspot.com/2008/02/android-sdk-m5-rc14-now-available.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
