Android :: Creating ViewHolders For ListViews With Different Item Layouts
Aug 18, 2010
I have a ListView with different layouts for different items. Some items are separators. Some items are different because they hold different kinds of data, etc.
I want to implement ViewHolders to speed up the getView process, but I'm not quite sure how to go about it. Different layouts have different pieces of data (which makes naming difficult) and different numbers of Views I want to use.
How should I go about doing this?
The best idea I can come up with is to create a generic ViewHolder with X items where X is the number of Views in an item layout with the highest number of them. For the other views with a small number of Views, I'll just use a subsection of those variables in the ViewHolder. So say I have 2 layouts I use for 2 different items. One has 3 TextViews and the other has 1. I would create a ViewHolder with 3 TextView variables and only use 1 of them for my other item. My problem is that this can get really ugly looking and feels really hacky; especially when an item layout may have many Views of many different types.
Here is a very basic getView:
CODE:..........
Suppose I had different types of row layouts, I could have a ViewHolder for each type of row. But what type would I declare "holder" to be at the top? Or would I declare a holder for each type and then use the one for the type of row I'm on.
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Aug 5, 2010
I have a ListView on my ListActivity and I'd like the rows of the ListView to be 1 of 3 different layouts. The first item in my list is always going to use layout A, the second item in my list is always going to use layout B, and all subsequent items are going to use layout C.
Here is my getView function: Code...
R.id.label1 and R.id.label2 are TextViews on R.layout.layout_A. However, txtLabel1 and txtLabel2 are null after trying to set them. Why?
I stepped through this code in the debugger and it inflated the correct layout (R.layout.layout_A) and fell into the correct case below to set the R.id.label1 and R.id.label2 text. Also, if there is a better way to do this, please let me know.
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Mar 31, 2010
I want to know how to change dynamically a ListView's item layout. To be exact, i want to know the method that the ListView's bindView method is called at runtime. if the bindView method is artificially called by a other method. then i will change a ListView's item layout.
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Mar 22, 2010
I have a ListView that is populated using an XML file. However, I want each item, when clicked, to start a new Activity related to that item. I understand how to use OnItemClick to start a Toast that shows the selected item's text. However, since the ListView is populated from an XML there is not a specific Id for each item in the list. So, how would I associate an Activity with each item in the ListView when the items do not have Ids?
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Mar 25, 2009
I am new to android and trying to create a customized list. Every item in the list has TextView and one Ratingbar. I now want add a couple of command buttons at the end of the list (like BACK, HOME, , NEXT). When I add these extra views to the layout xml file then they get added along with every item in the list. I think there should be another layout defined for the buttons to be displayed separate from the list. Anyone has an idea on how to do this?
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Nov 7, 2010
I am not very familiar with android coding so try to help me on a easy way.
The problem:
I have 2 Listviews and a onClick event handler.
How can i find out on which listview the user currently clicked?
public void onListItemClick(ListView l, View v, int position, long id) {
'Approach: if listview1 is clicked then FUNCTION1() else FUNCTION2()'}
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Sep 6, 2010
I'm creating a game where there's a screen that, for the most part, is shared by four different activites - but a key portion of the screen will be completely different, depending upon which activity is active. Basically, on the left will be an image of the player and along the bottom there will be a row of buttons (let's say for Armour, Weapons, Magic, Skills). This leaves the top-right portion, which will need to dynamically change to represent the button pressed. (So, one moment the top-right portion is the armour selection activity, and the next it's the weapon selection activity, and so on.)
Is this possible? Can I have a layout within a layout and dynamically point the nested layout at a (nested) layout.xml of my choosing? Or, am I looking at just duplicating most of the layout four times (for the four different activities?) Or, am I going to be looking at linking the four activities to a (the top-right) view component, and then having to dynamically construct all of *that* view's child views based on the currently active activity? Well, that's about as much sense as I can make this question make.
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Apr 9, 2010
I don't know exactly how to explain this problem, but I'll try. I have a ListView with several items. Each item has inside a TextView and two ImageView. I want the ImageView change when I click on them, and I want to open a context menu when I press for a long time into the ListView item.For the ImageView, everything works properly. For the whole item, I can show the context menu after a long press, but my problem is that the ImageView changes as well when I am pressing the TextView, for example.I hope you understand my problem. I think that all the children of a view are affected by an event in the parent, but I am not sure.
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Nov 20, 2010
I jave a list of item (linearlayout inside a scrollview where i add buttons vertically to linearlayout dynamically from the java code)i need when i click on one button the item moves up (scroll up) , to make the item at the first of the screen
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May 25, 2010
I need to get an item's position in spinner knowing it's ID. I've tried to do it with Spinner and SpinnerAdapter classes but there are no corresponding methods there.
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Sep 7, 2010
I have a ListView, and within each list item I have some TextViews and a CheckBox. When I check a CheckBox and my onCheckedChangeListener fires, everything works as it should. However, random other checkboxes get checked once one is checked. Here is an example.
If I click on the first CheckBox:
8 is checked.
15 is checked.
21 is checked.
27 is checked.
33 is checked.
41 is checked.
Then if I scroll all the way up, none are checked until 6. The next being 13.
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Apr 25, 2010
I'm trying to figure out how it's been designed. How it holds its items? How do I get a hold of the scrolling container? How can I know it's exact scrolling position? How can I scroll it to an exact position?
I want to have all the current benefits the ListView provides plus detailed scrolling control... How about animating from x to x+100 scroll position?
Maybe I need to create my own ListView? Where do I begin?
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Nov 18, 2009
Firstly, I have found many examples of how to grab data from a db and place it into a list, however this seems to be all for ListActivites.
My list is part of the UI and therefore I can't use a ListActivity because it does not consume the whole screen (or can I?).
This is the UI:
CODE:........
So, from what ive read I need to grab the data from the db, then place it into some sort of array then use an array adapter to fill the list view. Is that correct? If so, is there some sample code because all I can find is code releated to ListActivites.
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May 15, 2010
I am writing a software that i have to drill down on content a lot. For example when the program starts a listview is displayed. When user clicks on an item, then a second listview must be displayed. For example:
Select Continent > Select Country > Select State > Select City > Select Address
What is the best way to do this (less memory, faster, easier to code etc)? To create multiple listviews with multiple adapters? Or 1 listview with multiple Adapters? Lists are loaded from an external XML File.
So far i am creating a new adapter and setting it to the listview. How do i create a second listview and after clicking on 1st listview displaying the second one, with animation. Any examples? Extend my class to ListActivity or Activity?
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Oct 17, 2010
Trying to implement simple dictionary. I want to make it so while the user is typing in the EditText box the list to scroll automatically to the best match. I don't want it to filter the list. For example if the user types "s" in the EditText I want the first word that s/he sees under the EditText box to be the first word in the dictionary that starts with "s." But the user should still be able to slide up and down and to be able to see the entire list of words. It is basically like a go to functionality. I used ArrayList to store my list of words. The data is in res/raw/data.xml file. Here is my onCreate method
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
wordListView = (ListView)findViewById(R.id.wordList);
myEditText = (EditText)findViewById(R.id.myEditText);
words = new ArrayList<Word>();
arrAdap = new ArrayAdapter<Word>(this, android.R.layout.simple_list_item_1, words);
wordListView.setAdapter(arrAdap); try {
InputStream inSource = getResources().openRawResource(R.raw.data);
DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document doc = builder.parse(inSource, null);
NodeList wordsList = doc.getElementsByTagName("eng-bg");
int length = wordsList.getLength();
for(int i = 0; i<length; i++) {
Element entry = (Element)wordsList.item(i);
Element eng = (Element)entry.getElementsByTagName("english").item(0);
Element bul = (Element)entry.getElementsByTagName("bulgarian").item(0);
Element id = (Element)entry.getElementsByTagName("ID").item(0);
String english = eng.getFirstChild().getNodeValue();
String bulgarian = bul.getFirstChild().getNodeValue();
int wordId = Integer.parseInt(id.getFirstChild().getNodeValue());
Word word = new Word(bulgarian, english, wordId);
addNewWord(word);
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}wordListView.setOnItemClickListener(new OnItemClickListener(){
public void onItemClick(AdapterView<?> parent, View view, int pos, long id) {
selectedWord = words.get(pos);
showDialog(TRANS_DIALOG);
myEditText.setText(selectedWord.getEnglish());
myEditText.addTextChangedListener(new TextWatcher(){
public void onTextChanged(CharSequence s, int start, int before, int count) {
@Override
public void afterTextChanged(Editable s) {
// TODO Auto-generated method stub
@Override
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
// TODO Auto-generated method stub
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Aug 13, 2010
Hello, I need to put several listviews inner a LinearLayout. The Listviews should be wrap content to adapt the listview to their items. I need have one only scroll with which I can scroll all the listviews. I know that i can't use a scrollview because the listviews have their own scroll (but i don't need the scrolls of the listviews because i have them in wrap-content). I thought maybe puting the listviews inside the LinearLayout I will hadn't problems with the scrollview, but it didn't work, the LinearLayout was fixed to the screen, the scrollview didn't appear and the listviews ended scrollable. Without the scrollview if i have the list in wrap-content, their shown properly but i haven't any scroll and i can't see the lisviews below the screen. Really i have had this bug for one month and i haven't found any solution,
My code:
CODE:............
JAVA
CODE:...............
How you can see i create the lisviews dinamically and i put indside the layout with a secttion header. if you have some doubt ask me I need find a solution soon.
Sample Image: http://www.freeimagehosting.net/image.php?6dea1468bd.png
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Oct 11, 2010
I wish to work with checked list views wherein only one item can be selected at a time. Some queries related to this:
1) Is it advised to work with CheckedTextView as the ListView items, or a combination of CheckBox and TextView?
2) If using CheckedTextView, the text comes first and the checkbox appears on right edge. Is it possible to make the checkbox come on the left of the TextView?
3) How can I make one of the items as checked in onCreate()?
I am using array adapter and calling setAdapter() to populate list.
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Aug 16, 2009
I want to show many listviews in one activity. Something like
Textview Listview TextView Listview ..........
Every listview has different type of adapter. For this, I made the activity class like:-
CODE:........................
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Apr 20, 2009
Just looking at options for data updating affecting items in a ListView and have hit a few issues/queries.
There seems to only be notifyDataSetChanged() and notifyDataSetInvalidated(). While I could use notifyDataSetChanged() I am most likely in my case to have the scenario where additional data has been added and it seems inefficient to say the data has changed, which can only be resolved by calling getCount() and then getView() for all displayed items where knowing the data has been appended would just require adjusting the scrollbar. Is there some way to achieve something similar to this as the market seems happy populating dynamically in a manner that seems to reflect my desired behaviour (unless it just refreshes it all that fast).
Next question is the situation where the data behind just one item has changed. For instance I may wish to download icons in a background thread, but display available information with a placeholder icon. The best idea I've had so far is to store a map of indexes and views in my adapter which I can check against then call getView directly myself to have the view recycled with the new data. I'd just need additional logic to handle removing the map when the view gets destroyed or when it's recycled in getView. Either a bi-directional map (do we have one of those?) or two maps. Is the above likely to be my best approach or is there something built-in/better to get it done.
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Jul 22, 2010
In my app, I have different activities with listviews. The datas come from a server with a REST method, and it's only done once, when I start the application.
The pattern that I'd like to set is to precharge all the listviews with the JSONs that I already have in local, and in parallel, launch a thread that get the new JSONs files with my REST methods, and then update the listviews.
For now, when I start the app, I parse my JSONs files, and build all the lists of objects. I access them later in a static way, from my lists adapters.
So I would like to know the best way to launch this REST thread, and update the listview. Should I use AsyncTask ? A service ? and then, when I update my local JSONs, I have to re-parse them, updates the lists of object, and call in my adapters NotifyDataChanged ?
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Mar 22, 2010
Can I have two ListViews on a single ListActivity? I have built the xml file easy enough, but the code around ListActivity, setListAdapter(), getListView() and the like, all seem to be designed around one ListView per activity. How to get 2 ListViews in one screen?
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Nov 8, 2010
I'm not looking for exact code here, just a direction on what to look for and what I should be reading about so I can figure this out. I have a layout that I would like to remain static, with only the listview changing depending on what's selected from the list. I've reloaded data in the list, but I would like the fancy transition animations between choices, and would like the app to go to the previous menu when pressing back.
Someone suggested using a viewswitcher, which seems like it'd be great, but I am still unsure about how to fill a listview in a layout with a regular row layout, then on selection do an animated transition to a custom row. Also, it seems the viewswitcher is limited to two views, so it may be a limitation when I want to go a few menus deeper. Preferably, I'd like to put each menu in it's own class so that I can handle filling it in that class, if possible...
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Mar 25, 2009
I am trying to design a UI which utlizes two ListViews on the screen at the same time. Is this possible ?
So here is a quick example of how I was intending to do this.
1) Create an XML which positions 2 ListViews one onto of the other each ListView having there own ID
<ListView android:id="@android:id/list" android:layout_width="fill_parent" android:layout_height="198px"
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Apr 18, 2010
I guess my previous question wasn't clear enough ( http://stackoverflow.com/questions/2549585/android-failed-to-setcontentview-when-switching-to-listactivity ), so I explain as follows.
In my app I have two listactivities which uses two different listviews:
CODE:.......
As required by android, listview must have an ID which is exactly "@android:id/list". If I set the listview in both listview1 and listview2 with the same ID, then they will end up using the same format of listview, which is not what I want. But if I set one of the IDs to be sth like "@+id/listview2", android gave me the error: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
My listview is sort of complicated, customed list with image icons and text, so in my code, I also extended the ListAdapter:
CODE:........
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Oct 2, 2010
I'm having a several issues with ListViews.
The first problem is the layout that I use for every row of the listview. When I click in a row I've programmed that it expands with some other views. All works fine, but when I try to click again for shrink it, it seems that it's no focusable and doesn't highlight and, of course, it doesn't shrink. If I change the deprecated singleLine in the XML to inputType="text" all works fine but the row never highlithts.
The second problem goes when I try the method that Romain Guy said about the RelativeLayouts and the alignwithParentIfMissing. No matter whatever I try, but it seems impossible to implement in a ListView.
Another problem is with ellipsize, but it looks is a Android SDK bug and only works fine if I set singleLine in the attributes of the TextView
Well, I hope someone can helps me. I put the code of the listview and the XML of the layout. If you need some more code or information, as if you find any improvement or error.
CODE:..............
About the response of adamp, I've done this:
CODE:.......................
And finally, I have this listener:
CODE:..........
Once I've done that, there is no change about the behaviour of the listview. But I noticed that only I can expand the row clicking in the textview, if I click inside the row but in a empty area nothing happens.
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Aug 26, 2009
This application I've been working on has databases with multiple megabytes of data to sift through. A lot of the activities are just ListViews descending through various levels of data within the databases until we reach "documents", which is just HTML to be pulled from the DB(s) and displayed on the phone. The issue I am having is that some of these activities need to have the ability to search through the databases by capturing keystrokes and re-running the query with a "like %blah%" in it. This works reasonably quickly except when the user is first loading the data and when the user first enters a keystroke. I am using a ResourceCursorAdapter and I am generating the cursor in a background thread, but in order to do a listAdapter.changeCursor(), I have to use a Handler to post it to the main UI thread. This particular call is then freezing the UI thread just long enough to bring up the dreaded ANR dialog. I'm curious how I can offload this to a background thread totally so the user interface remains responsive and we don't have ANR dialogs popping up.
Just for full disclosure, I was originally returning an ArrayList of custom model objects and using an ArrayAdapter, but (understandably) the customer pointed out it was bad memory-manangement and I wasn't happy with the performance anyways. I'd really like to avoid a solution where I'm generating huge lists of objects and then doing a listAdapter.notifyDataSetChanged/Invalidated()
Here is the code in question:
CODE:.....................
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Dec 16, 2009
I used two listviews like this if my problem is one back line is coming inbetween two listviews.But i dont want that that balck line in betweem them.
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Jan 7, 2010
In my ListActivity, I need header and footer views (on the top and bottom of the list) to be used as previous page and next page buttons on my list, respectively, because I want to display only 20 items at a time.
I set my header and foot views by doing:
CODE:............
This works fine, but I need to dynamically remove and add these header and footer views, because some pages of my list may not have a next page button or a previous page button.
The problem is, I cannot call addHeaderView or addFooterView after I have called setListAdapter.
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Nov 19, 2010
The Twitter application for Android has a nice way of refreshing the listview by pulling down and automatically refreshing the data source.
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Apr 5, 2010
I want to have multiple listviews in single activity. But only one listview should be displayed at one time. The listviews will be loaded dynamically. So, how can I fill all the four listviews at the same time and display only one?
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