Android :: ListView Scrolling - Array Contain Large Number Of Items

Jun 27, 2010

I have a ListView with a scrolling issue. The Array contain a large number of items. When I try to scroll down, the listview displays the first items again. For example, if the initial view shows 12 items and I scroll down to view the next three, instead of showing 4 through 15, if shows 4 through 12 followed by 1, 2, and three. Debugging the Adapter reports that getView return 4 through 15 just as I would expect.

Android :: ListView Scrolling - Array Contain Large number of items


Android :: ListView Large Number Of Items - Best Practices

Oct 20, 2010

I am working with a ListView, custom adapter and a large number of items. I read in a book for Android that is was more efficient to use what it called the holder pattern. That is to create a wrapper class for each view in the list view that cached the objects in the view so as to avoid calls to findViewById because those are supposed to be expensive. My question is what is better? To have 50,000 objects GC'd every time the user scrolls or to make the 4 or five calls to findViewById per view? Below is my implementation of what the book suggested.

@Override public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView; if (view == null) {
final LayoutInflater inflater = (LayoutInflater)
context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(R.layout.survey_item, null);
view.setTag(new SurveyItemWrapper(view));
} bindView((SurveyItemWrapper) view.getTag(), position);
return view; } private void bindView(SurveyItemWrapper surveyItemWrapper, int position)
{ final SurveyedItem surveyedItem = surveyedItems.get(position);
surveyItemWrapper.getDescription().setText(surveyedItem.getItemName());
surveyItemWrapper.getCube().setText(String.format("%9.2f", surveyedItem.getCube()));
surveyItemWrapper.getShipping().setText(String.format("%d", surveyedItem.getShipping()));
surveyItemWrapper.getNotShipping().setText(String.format("%d", surveyedItem.getNotShipping()));
} private class SurveyItemWrapper { private TextView description;
private TextView cube; private TextView shipping;
private TextView notShipping; private View view;
public SurveyItemWrapper(View view) { this.view = view;
} public TextView getDescription() {
if (description == null) { description = (TextView) view.findViewById(R.id.SurveyItemDescription); } return description;
} public TextView getCube() { if (cube == null) {
cube = (TextView) view.findViewById(R.id.SurveyItemCube);
} return cube; } public TextView getShipping() {
if (shipping == null) { shipping = (TextView) view.findViewById(R.id.SurveyItemShipping);
} return shipping;} public TextView getNotShipping() {
if (notShipping == null) { notShipping = (TextView) view.findViewById(R.id.SurveyItemNotShipping); } return notShipping; } }

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Android :: ListView Set Number Of Items To Show

Mar 4, 2010

How can i set the number of items to show in a list without to scroll?

Example: I have a list with 10 items.

I want that only 3 items appears and that I have to scroll to see the rest of the items.

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Android :: How To Update CursorAdapter Tied To Listview When Number Of Items Changes?

Aug 16, 2010

I have a ListView backed by a custom adapter based on a CursorAdapter.The cursor I give it is based on a list of Notes in the database (each note is a DB row).Everything works just fine until I delete a note from the database. I'm not sure how to properly update the cursor/adapter/listview to display the new data.I've read conflicting posts on using adapter.notifyDataSetChanged() vs cursor.requery() to refresh the UI, but neither of them seems to work in this case.The only way I've been able to refresh it is by creating a new cursor from a new query and calling adapter.changeCursor(newCursor).Could someone demonstrate the proper way to update the backing data and then the UI (with psuedocode if possible).

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Android :: Android - Continue Scrolling In ListView With Clickable Items In Rows

Nov 19, 2010

I've been trawling the internet looking for an answer for several hours, but I can't seem to find anyone who has been able to solve this. I've got a listview which uses enter code herea custom adapter. A row looks like this. The list is filled by an array. Everything works great. Now, I want the ImageView and the ToggleButton to react to clicks, so I implement the OnClickListener in my adapter, put the items position in each view's tag, and then I set their onclicklistener to this. Works great, except now I can't use the onListItemClick for starting an activity for the item! OK, I say, I just make the relativelayout holding the text in the middle there use the same onclicklistener. Works great. Everything is clickable, and life is good.

EXCEPT! Now, when I scroll the list, I cannot "continue" the scroll by just flinging again. This causes the scrolling to stop, and I have to fling once more to get it going again. It seems the onclick-thingy causes the fling-motion to be interpreted as a tap or something (it does not trigger the logic within onClick).
I know that this is possible by just going to the phone list on my HTC Hero, which has exactly the kind of layout and behaviour I want from my app. This app even seems to have the onItemClickListener working. So how can I make sure the list keeps scrolling, and still be able to click the togglebutton, listitem and the imageview? I've been stuck on this all day, and it's giving me a headache

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Android :: Get Number Of Selected Items In Android ListView

Oct 9, 2010

I have a multiselection listview in my android app. What I need to know is how many items on that list I have selectet.

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Android :: Best Approach To Transfer Large Video Files Into Byte Array?

Apr 8, 2010

Please could anyone suggest an approach for transferring a >2MB video from a ContentResolver into a Bytestream, without running out of memory?
See question: http://stackoverflow.com/questions/2599305/android-outofmemoryerror-w...

Here's the current code, which throws an OutOfMemoryError on the byteBuffer.write(buffer, 0, len) line when transferring large videos:

// get bytestream to upload videoByteArray = getBytesFromFile(cR, fileUriString);
public static byte[] getBytesFromFile(ContentResolver cR, String fileUriString) throws IOException { Uri tempuri = Uri.parse(fileUriString);
InputStream is = cR.openInputStream(tempuri);
byte[] b3 = readBytes(is); is.close(); return b3;
}

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Android :: How To Keep ListView Header From Scrolling With ListView Content?

Jun 24, 2009

There must be a way to do this. How can you tell a ListView that has a header to not scroll it when the user scrolls the contents? I want it to stay in a "stuck" position so that the user can always see what column the content applies to.

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Android :: Scrolling Large Image - Working Good But Slow

Nov 12, 2009

For a project, I'm displaying an image with sizes 800 x 600 and I've implemented my custom scrolling (horizontal and vertical) - which is works fine. However, my problem is that it's not fast enough. If you continuously move your finger on screen for instance, scrolling is not responding fast enough. There is a lag and you need to wait (say 400-500ms) for new scrolled image to be loaded. Now below I described how I implemented scrolling and my question is that
- How can I make it faster, if possible - Is there any other better way to implement this.

My custom scrolling solution:
* I have a Main activity, SurfaceView and a thread
* In main activity, I'm using GestureDetector and override onScroll method.
* In onScroll method of activity, I'm passing values to SurfaceView's "handleScrolling" method.
* In "handleScrolling" method, I'm calculating proper values and using "newImage = Bitmap.createBitmap(myImage, starX, stopY, SCREEN_WIDTH, SCREEN_HEIGHT)"; to create a new, "scrolled" image.
* Then in thread loop, I'm drawing this "newImage" to canvas.

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Android :: Display Particular Array Of Items From Database - SQLServer - In Spinner

Jan 28, 2010

How can I display a particular array of items from a database (SQLServer) in a Spinner of Android?

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Android :: Items Are Shrank When While Scrolling View

Jun 8, 2010

I found strange behavior in ListView. I have ListView of TextView except from one entry that contains ImageView. when i on of the items is touched and scroll up and down the image is re-sized to about 2/3 its original size! Usually, the image remains in this smaller size when the user lifts his finger and stops scrolling. The original size can be restored by tapping your finger on any of the empty list cells.

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Android :: Webview Scrolling - Cannot Get Coordinates Of Searched Items

Feb 17, 2009

I have a webview in a scrollview. Webview displays my text. I have a searching feature also. It highlights my searched term. Now I want to scroll to that searched string. It should automatically scroll to that searched term. How can I do that? I tried with methods like scrollTo and scrollBy. They will not work as I cannot get the coordinates of searched term.

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Motorola Droid :: New Update Has Give Me Some Scrolling Lag On Certain Large Websites

Dec 9, 2009

The new update has give me some scrolling lag on certain large websites such as. Ign.com androidforums.com and doubletwist.com Someone please check And confirm this. How can we fix this?

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Android : EditText Items In A Scrolling List Lose Their Changes When Scrolled Off Screen

Jun 14, 2010

I have a long scrolling list of EditText items created by a SimpleCursorAdapter and prepopulated with values from an SQLite database. I make this by: cursor = db.rawQuery("SELECT _id, criterion, localweight, globalweight FROM " + dbTableName + " ORDER BY criterion", null); startManagingCursor(cursor); mAdapter = new SimpleCursorAdapter(this, R.layout.weight_edit_items, cursor, new String[]{"criterion","localweight","globalweight"}, new int[]{R.id.criterion_edit, R.id.localweight_edit, R.id.globalweight_edit}); is.setListAdapter(mAdapter); The scrolling list is several emulator screens long. The items display OK - scrolling through them shows that each has the correct value from the database. I can make an edit change to any of the EditTexts and the new text is accepted and displayed in the box. if I then scroll the list far enough to take the edited item off the screen, when I scroll back to look at it again its value has returned to what it was before I made the changes, ie. my edits have been lost. In trying to sort this out, I've done a getText to look at what's in the EditText after I've done my edits (and before a scroll) and getText returns the original text, even though the EditText is displaying my new text. It seems that the EditText has only accepted my edits superficially and they haven't been bound to the EditText, meaning they get dropped when scrolled off the screen. Can anyone please tell me what's going on here and what I need to do to force the EditText to retain its edits?

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HTC Incredible :: Track Pad Not Scrolling And Selecting Items Properly

Sep 10, 2010

The track pad on my Incredible seems to scroll and select items whenever it feels like it. Pressing on it seems to stop it but often it forces me to select whatever is highlighted to make it stop. I searched but so much clutter I didn't find anything on the forum about it.

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Android :: Broadcasting SMS - Message - Large Number Of SMS Are Being Sent

Sep 30, 2009

There seems to be a limit to the number of SMS that can be sent programmatically. It seems to be hovering around 70 to 100 messages. After a batch of messages, when I try to resend a batch I get a warning message "A large number of SMS are being sent. Press OK to continue or Cancel to stop sending" This requires user intervention and impedes the program from sending SMS. Is there a way around this error message? Maybe a way to turn off the warnings?

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Android :: Pass More Than One Array To A Listview?

Jan 7, 2010

I am using a listview to display items.
Currently I am passing an String array of items to it.
But I want to pass one more array and display its items alongwith the items of the first array(i.e somehow two lines of text).
How can I do that?

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Android :: Best Way To Save Large Number Of Checkboxes State In Droid?

Sep 11, 2010

I have some 34 checkboxes on one Activity which i have to mark and unmark. and I want to save the status of the each checkbox.

I want this persistently. So should i have a sqlite table or preferences ?

If sqlite table is recommended, then what should be the ideal table structure design?

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Android :: Getting Updated Array Of Data From ListView / Adapter

Aug 10, 2010

I must be missing something simple here.I've searched around but don't think my search query is touching on the right topics to yield results. Anyhow, what I'm after is running through the array of data I bind to a ListView after a "Submit" button has been clicked.

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Android :: How To Detect Particular View Longclicked From Array Listview?

Feb 18, 2010

I have an array list of a view in my application. The view has both single click and long click listeners. To detect a particular view that is selected I'm using isPressed() for single click listener. Now how can I detect that a particular view is longclicked from the array list of view?

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Android :: ListView Not Scrolling?

Jul 7, 2010

I'm trying to make a layout that is something similar to how the android market is...where say under comments there is what appears to be a ListView but it does not scroll (the whole page scroll but not the comments). I'm not sure if its even a ListView but I want something that looks like the list view (ie. have those divider bars and what not but NOT SCROLLABLE). There are people suggesting to use a LinearLayout instead of a ListView but I also what the items to be clickable and open a new activity. Please help?

My current layout tree is like so
<LinearLayout>
<ScrollView>
<RelativeLayout>

I am looking to put content inside the RelativeLayout.

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Android :: ListView Scrolling To Top

May 22, 2010

I have a ListView with custom rows. When any of these rows is clicked, the ListView's data is regenerated. I'd like the list to scroll back to the top when this happens.

I initially tried using setSelection(0) in each row's OnClickListener to achieve this but was unsuccessful (I believe because the ListView loses its scroll position when its data is invalidated - so my call to
setSelection is undone. I still don't understand how the ListView decides where to scroll to after invalidation, though).

The only working solution I know of was given by Romain Guy here: http://groups.google.com/group/android-developers/browse_thread/thread/127ca57414035301

It involves (View.post)ing the call to _listView.setSelection(0). I found this to perform quite poorly.
The newly generated list shows up with its scroll location unchanged and there is a considerable delay before it scrolls back to the top.

Is there any better way to achieve this functionality?

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Android :: Scrolling In A ListView?

Aug 19, 2010

In one of my projects I've got a ListView with hundreds of elements. But when scrolling through this list I get the following error:

CODE:.....................

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Android :: ListView For XML Data - Existing Array Or Database Cursors

Mar 16, 2009

Where could I find any examples of rendering XML data in a ListView? i.e, the model is read from a XML file, not in an existing array or database cursors.

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Android :: How To Get Header In Listview Without Scrolling

Dec 30, 2009

I want to display Header to my ListView. I used getListView ().addHeaderView() method to add header to Listview. but this is Header is scrolling with List.I want header should be constant.

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Android :: ListView Scrolling Very Slow

Oct 12, 2010

I am having a customized list view in my application, which is showing an image and text.

The Image I am getting from URL, using the code below:

CODE:..............

All is working perfect, except the list view scrolling, its very slow. If I disable the images, the scroll speed smooth-ens , but with the image enabled, it lags alot.

Is there any possible way I can reduce or remove this lagging?

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Android :: How To Get The ListView With Carousel Scrolling

Dec 24, 2009

I would like to have a ListView that scrolls in a carousel way, so when you scroll to the bottom and continue scolling, it should get back to the top element.

I do not want to use ViewSwitcher, nor ViewFlipper. How can I achieve that?

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Android :: OutOfMemoryError When Scrolling ListView

Jan 29, 2009

I'm having problems with ListViews in my application. I thought everything was fine until I noticed that if I scrolled up and down through the list quickly a number of times, sooner or later the app would crash with an OutOfMemoryError.

When I searched for the error I noticed a number of posts related to loading images. As my list items included a small arrow png, I assumed the problem lay here. However even after removing this and all other drawables I had (gradient background and list separator) the problem still remains.

Here's the stack trace

CODE:...............

I've had a look in DDMS and noticed that the percentage memory used in the heap doesn't go above 70%. Also, doesn't the reported 66K seem like a very small amount to be causing a crash?

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Android :: Disable ListView Scrolling?

Apr 24, 2010

I want to disable scrolling only of a ListView and keep it's items to still be click-able.

The idea is to control the scrolling via other means and not user touch. i.e. up/down buttons, or random scrolling...

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Android :: Stop Scrolling ListView?

Aug 5, 2010

I have a scenario, where I have three buttons(like tabs) and when clicking on each button, I am showing a listView, such that, I select one button and scroll the listView. During scrolling if I click on any other button, that list is also continue scrolling. Actually, I don't want the scrolling

When I click on any other button, it should not scroll and it should be in the starting position(means index 0).

I tried onScrollChangeListener(), in that onScrollStateChanged() is there.

I tried putting setSelection(0) in SCROLL_STATE_FLING & SCROLL_STATE_SCROLL state.

Its going to index zero, but continue from there, its still scrolling. How can I stop this scrolling.

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