Develop Reference

How to add some space in the middle of a listview?

I'm trying to add some extra space between the 4th and 5th items in the listview. What are my options?
I tried doing that in adapter's getView(), as well as manually getting access to the fourth element and adding padding to it.
Is there a better way to do this?

Another way to do this would be to use a different layout for the the 4th item (that has additional padding). It's similar to your solution but maybe a bit "cleaner". I'm assuming that you're extending ArrayAdapter.
In your adapter override the getViewTypeCount() method:
#Override public int getViewTypeCount() {
return 2;
}
This way you're telling your adapter that you will use two different layouts for your items. Next, you have to specify which items will be of which type by overriding another method:
#Override public int getItemViewType(int position) {
if(position == 3) {
return 0;
} else {
return 1;
}
}
This will tell your adapter to use a different view (only) for the 4th element in the list, and it will not be reused for other elements. Now for the last part, override onCreateView():
#Override public View getView(int position, View convertView, ViewGroup parent) {
if(convertView == null) {
LayoutInflater inflater = LayoutInflater.from(context);
if(position == 3) {
convertView = inflater.inflate(R.layout.your_layout_with_padding, parent, false);
} else {
convertView = inflater.inflate(R.layout.your_regular_item_padding, parent, false);
}
//TODO this is the place to initialize your view holder
} else {
//TODO this is the place to restore your view holder
}
//TODO setup your view here
return convertView;
}
For the item with position == 3 (4th item in the list) convertView argument of the getView() method will be null, because that is the first (and only) item of the type 1 in the list. Therefore you can inflate a different layout that includes a padding for that item.

I thought to some ways but if i have to be honest the only way to do this well is to change the layout in the adapter when the position is equal to 4. I meant that you can do an xml file with a RelativeLayout of the height that you want as space between the 4th and 5th element and set the visibility to gone and put him above all your adapter's elements. When the position is equal to 4 in your getView you set the visibility of that item to visible with nameOfYourRelativeLayout.setVisibility(View.VISIBLE)
So you can add this blank space only between 4th and 5th element. Mine is just a suggestion but i think it can work well.

Layout all of your items in the listview to include your data as well as a header view, maybe a textview or even a Viewgroup like another layout. Keep the header invisible until some logic in your code triggers (i.e. pos ==4) and make the header visible

ListView: how to access Item's elements programmatically from outside?

I have the following situation.
I have a ListView, each item of the ListView is comprised of different widgets (TextViews, ImageViews, etc...) inflated form a Layout in the getView() method of the custom adapter.
Now, I would like to achieve the following:
when a certain event is triggered I want to change the background of a View which is inside the item.
Please how do I do it?
This is the the Item Layout:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/cardlayout"
android:layout_width="320dp"
android:layout_height="130dp"
android:background="#android:color/transparent"
android:orientation="vertical"
android:paddingBottom="5dp"
android:paddingRight="5dp"
android:paddingTop="5dp" >
<FrameLayout
android:layout_width="320dp"
android:layout_height="117dp" >
<View
android:id="#+id/card"
android:layout_width="320dp"
android:layout_height="117dp"
android:background="#drawable/card_selector" />
</FrameLayout>
</LinearLayout>
I need to change the background of card
I have tried doing this:
View v=lv.getAdapter().getView(index, null, lv);
View card =(View)v.findViewById(R.id.card);
card.setBackgroundResource(R.drawable.pressed_background_card);
But no success :-((

When your event is triggered you should just call a notifyDataSetChanged on your adapter so that it will call again getView for all your visible elements.
Your getView method should take into account that some elements may have different background colors (and not forget to set it to normal color if the element doesn't need the changed background, else with recycling you would have many elements with changed background when you scroll)
edit :
I would try something like this :
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView == null)
{
convertView = LayoutInflater.from(getContext()).inflate(R.layout.card, parent, false);
}
//This part should also be optimised with a ViewHolder
//because findViewById is a costly operation, but that's not the point of this example
CardView cardView =(CardView)convertView .findViewById(R.id.card);
//I suppose your card should be determined by your adapter, not a new one each time
Card card = getItem(position);
//here you should check sthg like the position presence in a map or a special state of your card object
if(mapCardWithSpecialBackground.contains(position))
{
card.setBackgroundResource(specialBackground);
}
else
{
card.setBackgroundResource(normalBackground);
}
cardView.setCard(card);
return convertView;
}
And on the special event i would add the position of the item into the map and call notifyDataSetChanged.

Use the onitemclicklistener which has method onclicksomething..that takes four or five parameters. (View parent, View view, int position, int id). Use the view parameter to customize your background.
Update
Here's some of my code, If you don't understand I recommend to read about recycling and ViewHolder pattern.
#Override
public View getView(int position, View convertView, ViewGroup parent) {
{
ViewHolder viewHolder;
// If convertView isn't a recycled view, create a new.
if(convertView == null){
LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.row_gallery_frame, parent, false);
viewHolder = new ViewHolder();
// Here you must be able to find your Widget inside convertView and set a listener to it I guess?
viewHolder.nameHolder = (TextView) convertView.findViewById(R.id.nameTv);
// Set a reference to newly inflated view
convertView.setTag(viewHolder);
}
// If it is, then get the ViewHolder by tag
else{
viewHolder = (ViewHolder)convertView.getTag();
}
// Set the data
GalleryFrame galleryFrame = galleryFrameArrayList.get(position);
viewHolder.nameHolder.setText(galleryFrame.getName());
return convertView;
}
}
// Viewholder pattern which holds all widgets used
public static class ViewHolder{
public TextView nameHolder;
}

I assume you have a model object that you use to "draw" the list item , and for example the background color is determined based on a boolean or something.
All you need to do, is change the value on which you base your decision which background color should that TextView have.
Your getView() method should have code like that
if (myModelObj.isBrown()) {
myTextView.setBackgroundResource(R.drawable.brown_bg);
else
myTextView.setBackgroundResource(R.drawable.not_brown_bg);
All you should do when ur event is triggered, is set the value of the brown boolean in your model
and call notifyDataSetChanged() on your adapter
EDIT
If for some reason you don't wanna call nofitfyDataSetChanged(), althought it won't move the scroll position of your list and with the right recyclying it won't cause bad performance
You can find the View object that represent the list item you want to edit-if it's visisble-, and simply change the background in it, without refreshing the list at all.
int wantedPosition = 10; // Whatever position you're looking for
int firstPosition = listView.getFirstVisiblePosition() - listView.getHeaderViewsCount();
int wantedChild = wantedPosition - firstPosition
if (wantedChild < 0 || wantedChild >= listView.getChildCount()) {
// Wanted item isn't displayed
return;
}
View wantedView = listView.getChildAt(wantedChild);
then use wantedView to edit your background
This answer can be found here

try this one:
View v=lv.getAdapter().getView(index, null, lv);
View card =(View)v.findViewById(R.id.card);
card.setBackgroundResource(R.drawable.pressed_background_card);
card.invalidate();
v.invalidate();
those function force your views to redraw itself and they will render again.
look at invalidate()

What I normally do is this:
public static class EventDetailsRenderer {
private TextView title;
private TextView description;
private Event item;
public EventDetailsRenderer(View view) {
extractFromView(view);
}
private final void extractFromView(View view) {
title = (TextView) view.findViewById(R.id.EventTitle);
description = (TextView) view.findViewById(R.id.Description);
}
public final void render() {
render(item);
}
public final void render(Event item) {
this.item= item;
title.setText(item.getTitle());
description.setText(item.getDescription());
}
}
private class EventsAdapter
extends ArrayAdapter<Event> {
public EventsAdapter(Context context) {
super(context, R.layout.list_node__event_details, 0);
}
public void addAllItems(Event... services) {
for (int i = 0; i < services.length; i++) {
add(services[i]);
}
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
Event event = getItem(position);
EventDetailsRenderer eventRenderer;
if (convertView != null && convertView.getTag() != null) {
eventRenderer = (EventDetailsRenderer) convertView.getTag();
} else {
convertView = getActivity().getLayoutInflater().inflate(R.layout.list_node__event_details, null);
eventRenderer = new EventDetailsRenderer(convertView);
convertView.setTag(eventRenderer);
}
eventRenderer.render(event);
return convertView;
}
}
NOTE: that this example might not compile I pasted it from some code I have and deleted some lines to show an example but the logic it the same.
And then when you want to render it, just get the children from the list, iterate over them, check if the renderer contains the card you want to flip and call its render method... then you render a specific item in the list without effecting the rest of the items.
Let me know if this works...
Adam.

User EasyListViewAdapters library https://github.com/birajpatel/EasyListViewAdapters
Features
Easier than implementing your own Adapter (ie handling
BaseAdaper#getView).Very Easier to provide multi-row support.
Library takes care of recycling all views, that ensures performance
& helps your list view scroll smoothly.
Cleaner code. By keeping different RowViewSetter classes for
different row-types makes your code easy to manage & easy to reuse.
No data browsing, Library takes care of browsing data through
data-structure when View is being drawn or event occurs so that
Users does not have to look for their data to take actions.
Just by passing correct row-types library will Auto-map your
data-types to row-types to render views. Row views can be created by
using XML or Java (doesn't restrict to XML-Only Approach).
Load More callbacks can be registered to implement paginatation
support to your list.
Handling children viewclicks, you can also register for
Children(present inside your rows) view click events.
All these Views are registered with single OnClickListner so that
this mechanism is very memory efficient when click event occurs
users you gets clickedChildView, rowData,int eventId as callback
params.

Add a different element to ArrayAdapter/ListView

I have a ListView that's being populated by an ArrayAdapter:
someListView.setAdapter(adapter);
Each element in the adapter is inflated using the same layout.xml. Now I want to add an element of a different type (inflated using a different layout file) to the beginning of the ListView.
What I want to achieve is, to have a special element on top of all other elements in the list view, but also scrolls with the list (exits the screen from top if the user scrolls down).
I've tried to add the new element to the array but it's a different type so that won't work.
I've tried to insert a dummy element to the array at position 0, and modify the adapter's getView() so that if (position == 0) return myUniqueView, but that screwed up the entire list view somehow: items not showing, stuff jumping all over the place, huge gaps between elements, etc.
I start to think the best practice of achieving what I want, is not through editing the array adapter. But I don't know how to do it properly.

You don't need anything special to do what you ask. Android already provides that behavior built in to every ListView. Just call:
mListView.addHeaderView(viewToAdd);
That's it.
ListView Headers API
Tutorial

Do't know exactly but it might usefull
https://github.com/chrisjenx/ParallaxScrollView

In your adapter add a check on the position
private static final int LAYOUT_CONFIG_HEADER = 0;
private static final int LAYOUT_CONFIG_ITEMS = 1;
int layoutType;
#Override
public int getItemViewType(int position) {
if (position== 0){
layoutType = LAYOUT_CONFIG_HEADER;
} else {
layoutType = LAYOUT_CONFIG_ITEMS;
}
return layoutType;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
LayoutInflater inflater = null;
int layoutType = getItemViewType(position);
if (row == null) {
if (layoutType == LAYOUT_CONFIG_HEADER) {
//inflate layout header
}
} else {
//inflate layout of others rows
}
}

Hide items in a listview

I have tried to hide items in a custom list adapter. I can hide the visibility of the text but I cannot hide the whole list item. It still shows the dividers etc. I have tried:
tv.setVisibility(View.INVISIBLE);
tv.setVisibility(View.GONE);
convertView.setVisibility(View.INVISIBLE);
convertView.setVisibility(View.GONE);
When I use the convertView i get a null pointer exception.

You can set ContentView with No Element.
In getView() of Your Custom Adapter.
if(condition)
{
convertView=layoutInflater.inflate(R.layout.row_null,null);
return convertView;
}
else
{
convertView=layoutInflater.inflate(R.layout.row_content,null);
return convertView;
}
your XML row_null.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</LinearLayout>

You have 3 ways to do this:
Remove the items from your list inside or outside the adapter.
Inside the adapter you can do it in the Constructor.
private List<String> list;
public MyAdapter(Context context, List<String> list) {
list.remove(0);
list.remove(1);
list.remove(<whateverPositionYouLike>);
this.list = list;
}
You need to figure out how many items you want to hide and need to build a similar logic.
#Override
public int getCount() {
// In this adapter, we are supposed to hide the first item of the list view
// Returning 0 if no of items are already 0
if(list.size() <=1)
return 0;
// if number of items are more than one, returning one item less
return list.size() - 1;
}
#Override
public Object getItem(int position) {
// skipping the position
return list.get(position + 1);
}
`
#Override
public View getView(final int position, View v, ViewGroup arg2) {
// this is important, as we are supposed to skip the first item of listview
final int localPosition = position +1;
ViewHolderItem holder;
if (v == null) {
holder = new ViewHolderItem();
v = inflater.inflate(R.layout.list_row, null);
v.setTag(holder);
} else {
holder = (ViewHolderItem) v.getTag();
}
return v;
}
`
Answer provided by #hims_3009

You cannot in the way you are trying to, you'll need to use a custom Adapter and implement in there the logic for showing/not showing a line.

If you want to hide a row in a listview, you need to delete data in that position. For example if you use array adapter and want to hide the row on 5. position. You have to delete line from your array and the call notifyDatasetChanged() method.
(You can delete data from array by using tempArray)
or use this way
private List<String> items = new ArrayList<String>();
// make list a new array, clearing out all old values in it.
for(i=0; i<10; i++)
{
if((i != 5) && (i != 6)){
// if k = 5 or 6, dont add those items to the list
items.add(something[i]); /// whatever your list items are.
}
}
ArrayAdapter<String> itemList = new
ArrayAdapter<String>(this,R.layout.itemlistlayout);
setListAdapter(itemlist);

If you want to hide an entire item you need to build some logic into your getView() method to make it skip over various parts of your data.
lets say you have an ArrayAdapter and I want to hide the data that is at index 2. Your getView() method could look something like this.
#Override
public View getView(int pos, View convertView, ViewGroup, parent){
View mView = convertView;
//TODO: Check if convertView was null, and inflate
// or instantiate if needed.
//Now we are going to set the data
mTxt = mView.findViewById(R.id.mTxt);
if(pos >= 2){
//If position is 2 or above, we ignore it and take the next item.
mTxt.setText(this.getItem(pos + 1).toString());
}else{
//If position is below 2 then we take the current item.
mTxt.setText(this.getItem(pos).toString());
}
return mView;
}
Note that this example is generalized, it is not meant to be able to be dropped directly into your project. I had to make assumptions about some things which I don't know the truth on. You can use the same concept as I've shown here though and modify it to your situation to be able to "hide" rows in your ListView.

If you already have a custom list adapter you can just call notifyDataSetChanged() on the adapter and the adapter itself has of course to implement the logic to filter out the views for the rows you want to hide. These are the methods that come to my mind that need to reflect that logic:
#Override
public Object getItem(int position) {
return mItems.get(position);
}
#Override
public int getCount() {
return mItems.size();
}
#Override
public View getView(final int position, final View convertView, final ViewGroup parent) {
// here goes your logic to hide a row
Additionally you might have to change getItemId() as well.

I think I have a much easier / safer solution: you just have to "embed" your item in a Layout, and change the visibility of this parent layout.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<!-- Embed ListView Item into a "parent" Layout -->
<LinearLayout
android:id="#+id/parentLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<!-- This is the normal content of your ListView Item -->
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="World" />
</LinearLayout>
</LinearLayout>
Then in your code just do:
public View getView(int position, View view, ViewGroup parent) {
if (view == null) {
LayoutInflater li = mActivity.getLayoutInflater();
view = li.inflate(R.layout.my_listview_item, null);
}
LinearLayout parentLayout = (LinearLayout) view.findViewById(R.id.parentLayout);
if (shouldDisplayItem(position)) {
parentLayout.setVisibility(View.VISIBLE);
} else {
parentLayout.setVisibility(View.GONE);
}
return view;
}
This way you always use/reuse the same item, and just hide/show it.

Android customized row in listview can't recieve onItemClick

because I need to display something more than just a list in a Fragment.
So I choose Fragment rather than ListFragment, and my layout is something looks like
<linearlayout...>
<TextView...>...<TextView/>
<Button...>...<Button/>
<ListView android:id = "#"+id/mylist" ...></ListView>
</linearylayout>
And I implemnt "MyAdapter" extend BaseAdapter, which has getView like following
#Override
public View getView(int position, View convertView, ViewGroup parent)
{
if(position == 0)
{
return categroyView("Team leader");
}
else if (position == 2)
{
return categroyView("Team memebers");
}
else
{
LayoutInflater inflater = context.getLayoutInflater();
View v = inflater.inflate(R.layout.row_group, null, false);
return v;
}
}
protected View categroyView(String text)
{
TextView txtView = new TextView(context);
txtView.setText(text);
return txtView;
}
It turns out that I can receive onItemClick when its position is 0 or 2 (which as you can see I dynamically generate textView.
Meanwhile I can't receive onItemClick when its position is not 0 or 2 (which I return inflate view from XML)
I've seen some discussion about if customized row layout has some clickable item (like button), this situation will happen, but even my row layout has only one textView, it still failed to receive onItemClick.
p.s.
Also, I select Fragment rather than Activity for other other design issue.
I know I can alternatively add v.setOnClickListene in getView to help this issue, but then still the item won't highlight if I pressed on it.

What is in the position two view? If that thing might be able to take focus sit will do it instead of the list item if you don't want the inards to be clickabke then disable that it's click and it will the be passed to the item
Also are these long lists? You will run into trouble if you inflate a lot