Develop Reference

Animate ListView items on notifyDataSetChanged()

I want to add some animation to my ListView with SimpleCursorAdapter when my DB data changes.
I am using SimpleCursorAdapter with LoaderManager
I tried to add animation in getView method
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View view=super.getView(position, convertView, parent);
//My animation(nineoldandroid)
ObjectAnimator.ofFloat(view,"alpha",0,1).setDuration(500).start();
return view;
}
But this method animates all items, although some items were the same before updating.
Does Android have methods to detect which items need update, remove or add?
For example, maybe there are methods for getting changes between old and new cursor before calling myAdapter.swapCursor(newCursor); It would be possible to mark items(removed, updated, new) and make removing animation before swapping and ither animation in getView.
How can I solve this problem?

There are many ways to achieve this, you can try the answers in this question :
How to Animate Addition or Removal of Android ListView Rows
The 1st answer is working

No, at least I haven't found that Android can report to me if there are new or deleted items. I made something similar where the items of the ListView animate to their new positions and I had to track their positions myself to do that.
For your use case, it is probably easier to put the fading animation just before you delete the row from the database. So wherever in your code it is that you delete the row from the database and trigger a refresh, you do the fade animation on the item and on completion of the animation you delete the row and trigger a refresh.
Update
Hmmm, I read too quickly. Your example is not a fade-out on deleted items, but a fade-in on new items.
You will have to track item IDs yourself in your adapter. This approach can only work if you have a limited number of items to show because the list of previous item IDs will have to be stored in memory. If you can not be certain the list is never too large then you'll have to find a way to add the 'newness' information to the cursor itself.
Let me see if I can cook something up. Be back later...
Update 2
Below is a SimpleCursorAdapter that keeps track of the item ID from the previous cursor. In getView() it kicks of the fade-in animation if the requested view is for an item that was not present before.
private static class FadeInAdapter extends SimpleCursorAdapter {
private List<Long> previousItemIds = new ArrayList<Long>();
private FadeInAdapter(Context context, int layout, Cursor c, String[] from, int[] to, int flags) {
super(context, layout, c, from, to, flags);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View result = super.getView(position, convertView, parent);
// check if this view is for an item that is new
long itemId = getItemId(position);
if (!previousItemIds.contains(itemId)) {
// do the fade-in animation
result.setAlpha(0);
result.animate().alpha(1).setDuration(500).start();
}
return result;
}
#Override
public void changeCursor(Cursor cursor) {
Cursor oldCursor = getCursor();
if (oldCursor != null) {
// store previous item IDs to check against for newness with the new cursor
final int idColumnIndex = oldCursor.getColumnIndexOrThrow(DatabaseContract._ID);
previousItemIds.clear();
for (oldCursor.moveToFirst(); !oldCursor.isAfterLast(); oldCursor.moveToNext()) {
previousItemIds.add(oldCursor.getLong(idColumnIndex));
}
}
super.changeCursor(cursor);
}
}

Maybe RecyclerView helps. Try notifyItemChanged

how to change the background color of the last item added to the list view?

I am so confused with the list list view. I want to add an specific colur to the last added row to the list, how can I do that? I have googled all internet and stackoverflow for 2 days but I can't figure out how??
I have tried
lv.getChildAt(lv.getLastVisiblePosition()). setBackgroundColor(Color.RED);
but no success so far. I get the randowm row coloured. But I only want to colour the most recent added item.
Could someone please advice me on that.
Any comment is highly appreciated.
Cheers

Adapters have a view recycler for efficiency reasons, so this is where the "randomness" comes from...
Anyway simply create a custom adapter that tracks the index of the last row added and in getView() check whether the current index matches this last index:
If so change the background color
If not restore the original background color.
Watch Android's Romain Guy explain the view recycler at Google Talks.
Here is an example extending ArrayAdapter:
public class MyArrayAdapter<T> extends ArrayAdapter<T> {
private int lastAdded;
public MyArrayAdapter(Context context, int textViewResourceId, List<T> objects) {
super(context, textViewResourceId, objects);
lastAdded = objects.size() - 1;
}
#Override
public void add(T object) {
lastAdded = getCount();
super.add(object);
};
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = super.getView(position, convertView, parent);
if(position == lastAdded) // Red
view.setBackgroundColor(0xffff0000);
else // Transparent
view.setBackgroundColor(0x00000000);
return view;
}
#Override
public void insert(T object, int index) {
lastAdded = index;
super.insert(object, index);
};
}
Note: This is not comprehensive. There are other ways to add data which you may or may not want to override depending the way you use the adapter.

with that call lv.getChildAt(lv.getLastVisiblePosition()) you're getting the last child that is visible AND currently on the screen.
If you want to change anything on the last item of your list you must inside the getView of your adapter to check if(position == getCount()-1){ } and do stuff to it there.

You can use a customadapter for this and overriding the getView() can help you to achieve your task.
public View getView (int position, View convertView, ViewGroup parent){
// some task
if(position == last) // once even try position == getCount()
{
set background color to the view
}
return convertView;
}
here last is the last item that you will be inflating to the listview(may be an arraylist or an array or someother one that suits your requirement)

Dynamically increase the size of the cell in a list view in Android based on Content size?

I am doing a project where i am a using a custom list view, which contains a textview. Data is coming from the server. I want to change the height of the cell, based on the data size. If the content is more than two lines, i have to trim it to two lines and show a see more button. On clicking the see more button expand the cell to show full details.I googled about it. But i cannot find any useful resource.Could any one help me to solve this, any useful links or suggestions?`

One way to do this is to first invalidate the listView forcing it to redraw the visible elements and then handle the layout change in the getView method of your adapter.
Try this:
Add a showTrimmed(int position, boolean value) method to your adapter. This will update a structure inside your adapter that keeps track of the list items that you want to trim or not trim. Then in the getView method, when creating the item view, you test if the current element should be trimmed or not and based on the result you create the proper view.
I did something similar to achieve a different but similar result and it works.
Remember to call invalidate after calling showTrimmed to force the listView to redraw the displayed items.
Edit: I post my code which is different from what you want to do but it's quite similar in the idea:
public class HeroListViewAdapter extends ArrayAdapter<Hero> {
public static int NO_POS = -1;
private List<Hero> heroes;
private int selected_pos = NO_POS;
public HeroListViewAdapter(Context context, List<Hero> heroes){
super(context, R.layout.hero_list_item_view, heroes);
this.heroes = heroes;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View rowView = GuiBuilder.createHeroListItemView(heroes.get(position),getContext(),parent,false);
if(position == selected_pos){
rowView.setBackgroundColor((rowView.getResources().getColor(R.color.list_item_selected_color)));
}
return rowView;
}
public void setSelectedPosition(int selected_pos){
this.selected_pos = selected_pos;
}
public int getSelectedPosition(){
return selected_pos;
}
public Hero getSelectedHero(){
if(selected_pos>=0 && selected_pos<heroes.size())
return this.getItem(selected_pos);
else
return null;
}
}
instead of setSelectedPosition you should have the showTrimmed method which updates an inner member as setSelectedPos does, in order to keep track of the trimmed state of every list item. Then in the getView method you do the test (like I do in if(position == selected_pos)) and then you build your custom trimmed or not trimmed list item based on the result of the test. My listener which uses these functions is:
listView.setOnItemClickListener(new AdapterView.OnItemClickListener(){
public void onItemClick(AdapterView<?> parent, View view, int position, long id){
list_adapter.setSelectedPosition(position);
listView.invalidate();
}
}
);
you can try to update this idea to your needs. In particular in my case I do this to highlight the clicked listview item by programmatically changing its background.

Different layout for the items in the listview

I have some extended cursor adapter, in witch I call super with the context and the resource layout for the item in the list, something like this.
call to super in my adapter:
super(activity, viewResource, c, false);
creation of my adapter:
new MyCursorAdapter(this, null, R.layout.my_list_item, null);
What I want to achieve is something like my stupid mock up made in paint.
Put into words I want to have different kinds of layout for the items, for example I want all even items to have layout1 and all odd to have the layout2. So far I am able to give only one layout in this case R.layout.my_list_item. Is it possible to dynamically change the layout ?
Is it possible to construct the adapter to have items with different layout ? My goal is to dynamically chose the layout of the item. I do not want to have just one layout for all of the items I want to have foe example two...
Thanks

Yes, you're going to have to do two things though. First, override the getItemViewType() method in your adapter so that you can be sure your bindView() only get's views that appropriate for a particular position in the list, like so:
public int getItemViewType(int position){
if(correspondsToViewType1(position)){
return VIEW_TYPE_1;
}
else(correspondsToViewType2(position)){
return VIEW_TYPE_2;
}
//and so on and so forth.
}
Once you do that, just have a simple test in your bindView() that checks to see what type of view it should have recieved and setup things accordingly like so:
public void bindView(View view, Context context, Cursor cursor){
if(correspondsToViewType1(cursor)){
//Now we know view is of a particular type and we can do the
//setup for it
}
else if(correspondsToViewType2(cursor){
//Now we know view is of a different type and we can do the
//setup for it
}
}
Note that you're going to have to have to different methods for correpondsToViewType, one that takes a cursor and one that takes an int (for a position). The implementation for these will vary depending on what you want to do.
Note that doing things this way will allow you to reuse potentially recycled views. If you don't do this, your app is going to take a huge performance hit. Scrolling will be super choppy.

I'm guessing your extending SimpleCursorAdapter from the name of your custom adapter. You will want to override the function getView in your adapter and depending on the object in the list inflate a different layout and return that view.
EX:
#Override
public View getView (int position, View convertView, ViewGroup parent)
{
Object myObject = myList.get(position);
if(convertView == null)
{
if( something to determine layout )
convertView = inflater.inflate(Layout File);
else
convertView = inflater.inflate(Some Other Layout File);
}
//Set up the view here, such as setting textview text and such
return convertView;
}
This is just an example and is somewhat sudo code so it will need some adjustments for your specific situation.

Just override the newView Method:
public class MyCursorAdapter extends CursorAdapter {
private final LayoutInflater inflater;
private ContentType type;
public MyCursorAdapter (Context context, Cursor c) {
super(context, c);
inflater = LayoutInflater.from(context);
}
#Override
public void bindView(View view, Context context, Cursor cursor) {
if( cursor.getString(cursor.getColumnIndex("type")).equals("type1") ) {
// get elements for type1
} else {
// get elements for type1
}
}
#Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
if( cursor.getString(cursor.getColumnIndex("type")).equals("type1") ) {
final View view = inflater.inflate(R.layout.item_type1, parent, false);
} else {
final View view = inflater.inflate(R.layout.item_type2, parent, false);
}
return view;
}

Problem setting row backgrounds in Android Listview

I have an application in which I'd like one row at a time to have a certain color. This seems to work about 95% of the time, but sometimes instead of having just one row with this color, it will allow multiple rows to have the color. Specifically, a row is set to have the "special" color when it is tapped. In rare instances, the last row tapped will retain the color despite a call to setBackgroundColor attempting to make it otherwise.
private OnItemClickListener mDirectoryListener = new OnItemClickListener(){
public void onItemClick(AdapterView parent, View view, int pos, long id){
if (stdir.getStationCount() == pos) {
stdir.moreStations();
return;
}
if (playingView != null)
playingView.setBackgroundColor(Color.DKGRAY);
view.setBackgroundColor(Color.MAGENTA);
playingView = view;
playStation(pos);
}
};
I have confirmed with print statements that the code setting the row to gray is always called.
Can anyone imagine a reason why this code might intermittently fail? If there is a pattern or condition that causes it, I can't tell.
I thought it might have something to do with the activity lifecycle setting the "playingView" variable back to null, but I can't reliably reproduce the problem by switching activities or locking the phone.
private class DirectoryAdapter extends ArrayAdapter {
private ArrayList<Station> items;
public DirectoryAdapter(Context c, int resLayoutId, ArrayList<Station> stations){
super(c, resLayoutId, stations);
this.items = stations;
}
public int getCount(){
return items.size() + 1;
}
public View getView(int position, View convertView, ViewGroup parent){
View v = convertView;
LayoutInflater vi = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (position == this.items.size()) {
v = vi.inflate(R.layout.morerow, null);
return v;
}
Station station = this.items.get(position);
v = vi.inflate(R.layout.songrow, null);
if (station.playing)
v.setBackgroundColor(Color.MAGENTA);
else if (station.visited)
v.setBackgroundColor(Color.DKGRAY);
else
v.setBackgroundColor(Color.BLACK);
TextView title = (TextView)v.findViewById(R.id.title);
title.setText(station.name);
return v;
}
};

ListViews don't create instances of contained views for every item in the list, but only for ones that are actually visible on the screen. For performance reasons, they try and maintain as few views as possible, and recycle them. That's what the convertView parameter is.
When a view scrolls off the screen, it may be recycled or destroyed. You can't hold a reference to an old view and assume that it will refer to the item you expect it to in the future. You should save the ID of the list item you need and look that up instead.
Moreover, there are a couple of other issues with your implementation (from a best practices standpoint). You seem to be ignoring the convertView parameter and creating a new view from scratch each time. That can cause your application to bog down a bit while scrolling if you have a long list. Secondly, instead of adding the "more" element the way you do, you're better of setting it with setFooterView().
There's an excellent talk on the ListView from Google I/O 2010 that covers these and other issues. It's an hour long, but definitely worth watching in its entirety.