How to refresh an Android ListView after adding/deleting dynamic data?
Call notifyDataSetChanged() on your Adapter object once you've modified the data in that adapter.
Some additional specifics on how/when to call notifyDataSetChanged() can be viewed in this Google I/O video.
Also you can use this:
myListView.invalidateViews();
Please ignore all the invalidate(), invalidateViews(), requestLayout(), ... answers to this question.
The right thing to do (and luckily also marked as right answer) is to call notifyDataSetChanged() on your Adapter.
Troubleshooting
If calling notifyDataSetChanged() doesn't work all the layout methods won't help either. Believe me the ListView was properly updated. If you fail to find the difference you need to check where the data in your adapter comes from.
If this is just a collection you're keeping in memory check that you actually deleted from or added the item(s) to the collection before calling the notifyDataSetChanged().
If you're working with a database or service backend you'll have to call the method to retrieve the information again (or manipulate the in memory data) before calling the notifyDataSetChanged().
The thing is this notifyDataSetChanged only works if the dataset has changed. So that is the place to look if you don't find changes coming through. Debug if needed.
ArrayAdapter vs BaseAdapter
I did find that working with an adapter that lets you manage the collection, like a BaseAdapter works better. Some adapters like the ArrayAdapter already manage their own collection making it harder to get to the proper collection for updates. It's really just an needless extra layer of difficulty in most cases.
UI Thread
It is true that this has to be called from the UI thread. Other answers have examples on how to achieve this. However this is only required if you're working on this information from outside the UI thread. That is from a service or a non UI thread. In simple cases you'll be updating your data from a button click or another activity/fragment. So still within the UI thread. No need to always pop that runOnUiTrhead in.
Quick Example Project
Can be found at https://github.com/hanscappelle/so-2250770.git. Just clone and open the project in Android Studio (gradle). This project has a MainAcitivity building a ListView with all random data. This list can be refreshed using the action menu.
The adapter implementation I created for this example ModelObject exposes the data collection
public class MyListAdapter extends BaseAdapter {
/**
* this is our own collection of data, can be anything we
* want it to be as long as we get the abstract methods
* implemented using this data and work on this data
* (see getter) you should be fine
*/
private List<ModelObject> mData;
/**
* our ctor for this adapter, we'll accept all the things
* we need here
*
* #param mData
*/
public MyListAdapter(final Context context, final List<ModelObject> mData) {
this.mData = mData;
this.mContext = context;
}
public List<ModelObject> getData() {
return mData;
}
// implement all abstract methods here
}
Code from the MainActivity
public class MainActivity extends Activity {
private MyListAdapter mAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView list = (ListView) findViewById(R.id.list);
// create some dummy data here
List<ModelObject> objects = getRandomData();
// and put it into an adapter for the list
mAdapter = new MyListAdapter(this, objects);
list.setAdapter(mAdapter);
// mAdapter is available in the helper methods below and the
// data will be updated based on action menu interactions
// you could also keep the reference to the android ListView
// object instead and use the {#link ListView#getAdapter()}
// method instead. However you would have to cast that adapter
// to your own instance every time
}
/**
* helper to show what happens when all data is new
*/
private void reloadAllData(){
// get new modified random data
List<ModelObject> objects = getRandomData();
// update data in our adapter
mAdapter.getData().clear();
mAdapter.getData().addAll(objects);
// fire the event
mAdapter.notifyDataSetChanged();
}
/**
* helper to show how only changing properties of data
* elements also works
*/
private void scrambleChecked(){
Random random = new Random();
// update data in our adapter, iterate all objects and
// resetting the checked option
for( ModelObject mo : mAdapter.getData()) {
mo.setChecked(random.nextBoolean());
}
// fire the event
mAdapter.notifyDataSetChanged();
}
}
More Information
Another nice post about the power of listViews is found here: http://www.vogella.com/articles/AndroidListView/article.html
Call runnable whenever you want:
runOnUiThread(run);
OnCreate(), you set your runnable thread:
run = new Runnable() {
public void run() {
//reload content
arraylist.clear();
arraylist.addAll(db.readAll());
adapter.notifyDataSetChanged();
listview.invalidateViews();
listview.refreshDrawableState();
}
};
i got some problems with dynamic refresh of my listview.
Call notifyDataSetChanged() on your Adapter.
Some additional specifics on how/when to call notifyDataSetChanged() can be viewed in this Google I/O video.
notifyDataSetChanged() did not work properly in my case[ I called the notifyDataSetChanged from another class]. Just in the case i edited the ListView in the running Activity (Thread). That video thanks to Christopher gave the final hint.
In my second class i used
Runnable run = new Runnable(){
public void run(){
contactsActivity.update();
}
};
contactsActivity.runOnUiThread(run);
to acces the update() from my Activity. This update includes
myAdapter.notifyDataSetChanged();
to tell the Adapter to refresh the view.
Worked fine as far as I can say.
If you are using SimpleCursorAdapter try calling requery() on the Cursor object.
if you are not still satisfied with ListView Refreshment, you can look at this snippet,this is for loading the listView from DB, Actually what you have to do is simply reload the ListView,after you perform any CRUD Operation
Its not a best way to code, but it will refresh the ListView as you wish..
It works for Me....if u find better solution,please Share...
.......
......
do your CRUD Operations..
......
.....
DBAdapter.open();
DBAdapter.insert_into_SingleList();
// Bring that DB_results and add it to list as its contents....
ls2.setAdapter(new ArrayAdapter(DynTABSample.this,
android.R.layout.simple_list_item_1, DBAdapter.DB_ListView));
DBAdapter.close();
The solutions proposed by people in this post works or not mainly depending on the Android version of your device. For Example to use the AddAll method you have to put android:minSdkVersion="10" in your android device.
To solve this questions for all devices I have created my on own method in my adapter and use inside the add and remove method inherits from ArrayAdapter that update you data without problems.
My Code: Using my own data class RaceResult, you use your own data model.
ResultGpRowAdapter.java
public class ResultGpRowAdapter extends ArrayAdapter<RaceResult> {
Context context;
int resource;
List<RaceResult> data=null;
public ResultGpRowAdapter(Context context, int resource, List<RaceResult> objects) {
super(context, resource, objects);
this.context = context;
this.resource = resource;
this.data = objects;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
........
}
//my own method to populate data
public void myAddAll(List<RaceResult> items) {
for (RaceResult item:items){
super.add(item);
}
}
ResultsGp.java
public class ResultsGp extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
...........
...........
ListView list = (ListView)findViewById(R.id.resultsGpList);
ResultGpRowAdapter adapter = new ResultGpRowAdapter(this, R.layout.activity_result_gp_row, new ArrayList<RaceResult>()); //Empty data
list.setAdapter(adapter);
....
....
....
//LOAD a ArrayList<RaceResult> with data
ArrayList<RaceResult> data = new ArrayList<RaceResult>();
data.add(new RaceResult(....));
data.add(new RaceResult(....));
.......
adapter.myAddAll(data); //Your list will be udpdated!!!
For me after changing information in sql database nothing could refresh list view( to be specific expandable list view) so if notifyDataSetChanged() doesn't help, you can try to clear your list first and add it again after that call notifyDataSetChanged(). For example
private List<List<SomeNewArray>> arrayList;
List<SomeNewArray> array1= getArrayList(...);
List<SomeNewArray> array2= getArrayList(...);
arrayList.clear();
arrayList.add(array1);
arrayList.add(array2);
notifyDataSetChanged();
Hope it makes sense for you.
If you want to maintain your scroll position when you refresh, and you can do this:
if (mEventListView.getAdapter() == null) {
EventLogAdapter eventLogAdapter = new EventLogAdapter(mContext, events);
mEventListView.setAdapter(eventLogAdapter);
} else {
((EventLogAdapter)mEventListView.getAdapter()).refill(events);
}
public void refill(List<EventLog> events) {
mEvents.clear();
mEvents.addAll(events);
notifyDataSetChanged();
}
For the detail information, please see Android ListView: Maintain your scroll position when you refresh.
Just use myArrayList.remove(position); inside a listener:
myListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override public void onItemClick(AdapterView<?> parent, android.view.View view, int position, long id) {
myArrayList.remove(position);
myArrayAdapter.notifyDataSetChanged();
}
});
You need to use a single object of that list whoose data you are inflating on ListView. If reference is change then notifyDataSetChanged() does't work .Whenever You are deleting elements from list view also delete them from the list you are using whether it is a ArrayList<> or Something else then Call
notifyDataSetChanged() on object of Your adapter class.
So here see how i managed it in my adapter see below
public class CountryCodeListAdapter extends BaseAdapter implements OnItemClickListener{
private Context context;
private ArrayList<CountryDataObject> dObj;
private ViewHolder holder;
private Typeface itemFont;
private int selectedPosition=-1;
private ArrayList<CountryDataObject> completeList;
public CountryCodeListAdapter(Context context, ArrayList<CountryDataObject> dObj) {
this.context = context;
this.dObj=dObj;
completeList=new ArrayList<CountryDataObject>();
completeList.addAll(dObj);
itemFont=Typeface.createFromAsset(context.getAssets(), "CaviarDreams.ttf");
}
#Override
public int getCount() {
return dObj.size();
}
#Override
public Object getItem(int position) {
return dObj.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View view, ViewGroup parent) {
if(view==null){
holder = new ViewHolder();
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(R.layout.states_inflator_layout, null);
holder.textView = ((TextView)view.findViewById(R.id.stateNameInflator));
holder.checkImg=(ImageView)view.findViewById(R.id.checkBoxState);
view.setTag(holder);
}else{
holder = (ViewHolder) view.getTag();
}
holder.textView.setText(dObj.get(position).getCountryName());
holder.textView.setTypeface(itemFont);
if(position==selectedPosition)
{
holder.checkImg.setImageResource(R.drawable.check);
}
else
{
holder.checkImg.setImageResource(R.drawable.uncheck);
}
return view;
}
private class ViewHolder{
private TextView textView;
private ImageView checkImg;
}
public void getFilter(String name) {
dObj.clear();
if(!name.equals("")){
for (CountryDataObject item : completeList) {
if(item.getCountryName().toLowerCase().startsWith(name.toLowerCase(),0)){
dObj.add(item);
}
}
}
else {
dObj.addAll(completeList);
}
selectedPosition=-1;
notifyDataSetChanged();
notifyDataSetInvalidated();
}
#Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
Registration reg=(Registration)context;
selectedPosition=position;
reg.setSelectedCountryCode("+"+dObj.get(position).getCountryCode());
notifyDataSetChanged();
}
}
Consider you have passed a list to your adapter.
Use:
list.getAdapter().notifyDataSetChanged()
to update your list.
After deleting data from list view, you have to call refreshDrawableState().
Here is the example:
final DatabaseHelper db = new DatabaseHelper (ActivityName.this);
db.open();
db.deleteContact(arg3);
mListView.refreshDrawableState();
db.close();
and deleteContact method in DatabaseHelper class will be somewhat looks like
public boolean deleteContact(long rowId) {
return db.delete(TABLE_NAME, BaseColumns._ID + "=" + rowId, null) > 0;
}
I was not able to get notifyDataSetChanged() to work on updating my SimpleAdapter, so instead I tried first removing all views that were attached to the parent layout using removeAllViews(), then adding the ListView, and that worked, allowing me to update the UI:
LinearLayout results = (LinearLayout)findViewById(R.id.results);
ListView lv = new ListView(this);
ArrayList<HashMap<String,String>> list = new ArrayList<HashMap<String,String>>();
SimpleAdapter adapter = new SimpleAdapter( this, list, R.layout.directory_row,
new String[] { "name", "dept" }, new int[] { R.id.name, R.id.dept } );
for (...) {
HashMap<String, String> map = new HashMap<String, String>();
map.put("name", name);
map.put("dept", dept);
list.add(map);
}
lv.setAdapter(adapter);
results.removeAllViews();
results.addView(lv);
while using SimpleCursorAdapter can call changeCursor(newCursor) on the adapter.
I was the same when, in a fragment, I wanted to populate a ListView (in a single TextView) with the mac address of BLE devices scanned over some time.
What I did was this:
public class Fragment01 extends android.support.v4.app.Fragment implements ...
{
private ListView listView;
private ArrayAdapter<String> arrayAdapter_string;
...
#Override
public void onActivityCreated(Bundle savedInstanceState)
{
...
this.listView= (ListView) super.getActivity().findViewById(R.id.fragment01_listView);
...
this.arrayAdapter_string= new ArrayAdapter<String>(super.getActivity(), R.layout.dispositivo_ble_item, R.id.fragment01_item_textView_titulo);
this.listView.setAdapter(this.arrayAdapter_string);
}
#Override
public void onLeScan(BluetoothDevice device, int rssi, byte[] scanRecord)
{
...
super.getActivity().runOnUiThread(new RefreshListView(device));
}
private class RefreshListView implements Runnable
{
private BluetoothDevice bluetoothDevice;
public RefreshListView(BluetoothDevice bluetoothDevice)
{
this.bluetoothDevice= bluetoothDevice;
}
#Override
public void run()
{
Fragment01.this.arrayAdapter_string.add(new String(bluetoothDevice.toString()));
Fragment01.this.arrayAdapter_string.notifyDataSetChanged();
}
}
Then the ListView began to dynamically populate with the mac address of the devices found.
I think it depends on what you mean by refresh. Do you mean that the GUI display should be refreshed, or do you mean that the child views should be refreshed such that you can programatically call getChildAt(int) and get the view corresponding to what is in the Adapter.
If you want the GUI display refreshed, then call notifyDataSetChanged() on the adapter. The GUI will be refreshed when next redrawn.
If you want to be able to call getChildAt(int) and get a view that reflects what is what is in the adapter, then call to layoutChildren(). This will cause the child view to be reconstructed from the adapter data.
I had an ArrayList which I wanted to display in a listview. ArrayList contained elements from mysql.
I overrided onRefresh method and in that method I used tablelayout.removeAllViews(); and then repeated the process for getting data again from the database.
But before that make sure to clear your ArrayList or whatever data structre or else new data will get appended to the old one..
If you want to update the UI listview from a service, then make the adapter static in your Main activity and do this:
#Override
public void onDestroy() {
if (MainActivity.isInFront == true) {
if (MainActivity.adapter != null) {
MainActivity.adapter.notifyDataSetChanged();
}
MainActivity.listView.setAdapter(MainActivity.adapter);
}
}
If you are going by android guide lines and you are using the ContentProviders to get data from Database and you are displaying it in the ListView using the CursorLoader and CursorAdapters ,then you all changes to the related data will automatically be reflected in the ListView.
Your getContext().getContentResolver().notifyChange(uri, null); on the cursor in the ContentProvider will be enough to reflect the changes .No need for the extra work around.
But when you are not using these all then you need to tell the adapter when the dataset is changing. Also you need to re-populate / reload your dataset (say list) and then you need to call notifyDataSetChanged() on the adapter.
notifyDataSetChanged()wont work if there is no the changes in the datset.
Here is the comment above the method in docs-
/**
* Notifies the attached observers that the underlying data has been changed
* and any View reflecting the data set should refresh itself.
*/
I was only able to get notifyDataSetChanged only by getting new adapter data, then resetting the adapter for the list view, then making the call like so:
expandableAdapter = baseFragmentParent.setupEXLVAdapter();
baseFragmentParent.setAdapter(expandableAdapter);
expandableAdapter.notifyDataSetChanged();
on other option is onWindowFocusChanged method, but sure its sensitive and needs some extra coding for whom is interested
override fun onWindowFocusChanged(hasFocus: Boolean) {
super.onWindowFocusChanged(hasFocus)
// some controls needed
programList = usersDBHelper.readProgram(model.title!!)
notesAdapter = DailyAdapter(this, programList)
notesAdapter.notifyDataSetChanged()
listview_act_daily.adapter = notesAdapter
}
If I talked about my scenario here, non of above answers will not worked because I had activity that show list of db values along with a delete button and when a delete button is pressed, I wanted to delete that item from the list.
The cool thing was, I did not used recycler view but a simple list view and that list view initialized in the adapter class. So, calling the notifyDataSetChanged() will not do anything inside the adapter class and even in the activity class where adapter object is initialized because delete method was in the adapter class.
So, the solution was to remove the object from the adapter in the adapter class getView method(to only delete that specific object but if you want to delete all, call clear()).
To you to get some idea, what was my code look like,
public class WordAdapter extends ArrayAdapter<Word> {
Context context;
public WordAdapter(Activity context, ArrayList<Word> words) {}
//.......
#NonNull
#Override
public View getView(final int position, View convertView, ViewGroup group) {
//.......
ImageButton deleteBt = listItemView.findViewById(R.id.word_delete_bt);
deleteBt.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (vocabDb.deleteWord(currentWord.id)) {
//.....
} else{
//.....
}
remove(getItem(position)); // <---- here is the trick ---<
//clear() // if you want to clear everything
}
});
//....
Note: here remove() and getItem() methods are inherit from the Adapter class.
remove() - to remove the specific item that is clicked
getItem(position) - is to get the item(here, thats my Word object
that I have added to the list) from the clicked position.
This is how I set the adapter to the listview in the activity class,
ArrayList<Word> wordList = new ArrayList();
WordAdapter adapter = new WordAdapter(this, wordList);
ListView list_view = (ListView) findViewById(R.id.activity_view_words);
list_view.setAdapter(adapter);
After adding/deleting dynamic data in your "dataArray" do:
if you use an ArrayAdapter
adapter.notifyDataSetChanged();
if you use a customAdapter that extends ArrayAdapter
adapter.clear();
adapter.addAll(dataArray);
adapter.notifyDataSetChanged();
if you use a customAdapter that extends BaseAdapter
adapter.clear();
adapter.getData().addAll(dataArray);
adapter.getData().notifyDataSetChanged();
The easiest is to just make a new Adaper and drop the old one:
myListView.setAdapter(new MyListAdapter(...));
Related
i am using a recyclerView and loading the data from database.The recyclerView item have 2 buttons. The recyclerView loads fine and clicks work fine for the following code.
allData=db.getCatData(CATEGORYLIST_CIDD,1);
textlistadapter = new TextListAdapter(getActivity(), allData);
recyclerView.setAdapter(textlistadapter);
later i rearrange the adapter data for displaying the data in descending order by using this code
db=new DatabaseHandler(getActivity().getApplicationContext());
allData=db.getCatData(CATEGORYLIST_CIDD,order_id);
textlistadapter = new TextListAdapter(getActivity(), allData);
recyclerView.setAdapter(textlistadapter);
textlistadapter.notifyDataSetChanged();
Now the items are rearranged on the recyclerView, but the onShareButtonClickListener returns null, here is the code of the adapter.
private OnShareButtonClickListener onShareButtonClickListener;
public interface OnShareButtonClickListener {
void onItemClick(View view, Pojo obj, int position);
}
public void setOnShareButtonClickListener(final OnShareButtonClickListener onShareButtonClickListener) {
this.onShareButtonClickListener = onShareButtonClickListener;
}
the click listener code is here
holder.bt_share.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//Snackbar.make(view, "Share Clicked", Snackbar.LENGTH_SHORT).show();
if (onShareButtonClickListener != null) {
onShareButtonClickListener.onItemClick(view, c, position);
}
}
});
The click does not work since the onShareButtonClickListener is null.
The same code works well for the first time and once i change the order then the click events are not working, all other functions are working well.
you should only need to do this once:
textlistadapter = new TextListAdapter(getActivity(), allData);
recyclerView.setAdapter(textlistadapter);
later on, if you want to update/change the data, then you should do something like this:
textlistadapter.setListItems(allData);
textlistadapter.notifyDataSetChanged();
Where setListItems() is a public method in your adapter, an example like this:
public void setListItems(List<> allData) {
this.data.clear();
this.data.addAll(allData);
}
It's easy to understand what you are doing wrong. You populate an array which will feed your adapter with data, that meaning that, after setting the adapter, if you want it's data to change, you only need to change the array you populated the data with, and notify the adapter for the data change.
For example:
myData = db.getData();
myAdapter = new MyAdapter(this,myData);
recyvlerview.setAdapter(myAdapter);
Now every time you want to change the data, you only need to change your myData and notifity the adapter
myAdapter.notifyDataSetChange();
Basically instead of doing this:
db=new DatabaseHandler(getActivity().getApplicationContext());
allData=db.getCatData(CATEGORYLIST_CIDD,order_id);
textlistadapter = new TextListAdapter(getActivity(), allData);
recyclerView.setAdapter(textlistadapter);
textlistadapter.notifyDataSetChanged();
This should suffice
db=new DatabaseHandler(getActivity().getApplicationContext());
allData=db.getCatData(CATEGORYLIST_CIDD,order_id);
textlistadapter.notifyDataSetChanged();
I have a simple adapter
public class ConversationListAdapter extends
RecyclerView.Adapter<Conversation.ViewHolder> {
private List<Conversation> items;
private Activity activity;
public ConversationListAdapter(Activity activity, List<Conversation> items) {
super();
this. items = items;
this.activity = activity;
}
#Override
public void onBindViewHolder(ViewHolder viewHolder, int i) {
Conversation conversation = mItems.get(i);
viewHolder.name.setText(conversation.getName());
if ( conversation.getUrl() != null) {
Picasso.with(activity.getApplicationContext()).load(conversation.getUrl())
.into(viewHolder.imageView);
}
}
and a basic
class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {..}
}
Now in the fragment as always:
mRecyclerView.setAdapter(new ConversationAdapter(getActivity(), mItems));
Now Im calling my rest api to get the data and the first time it works great everything is where it should be (let's say in c there is only 2 items and the order is conv1 and conv2)
private void handleResult(List<Conversation> c) {
items.clear()
items.addAll(c)
adapter.notifyDataSetChanged()
}
But... now if I refresh for example and the data in the List comes in a different order (conv2 and then conv1) after the adapter.notifyDataSetChanged() both of my imageView in the list have the same pictures.. ! But the textView however has the right text
This only happens with view filled with Picasso and cannot understand why
Could someone help me on this ?
you use if condition in any adapter you also have to set else part of it. i also don't know exactly why this is happen that if condition is given it takes same condition for child which are not match this, may be a bug in android. please try else part of it also. may be this work for you.
You have to replace your items in your adapter or create a new adapter with the new items
1st solution:
private void handleResult(List<Conversation> c) {
mRecyclerView.setAdapter(new ConversationAdapter(getActivity(), c));
}
2nd solution:
private void handleResult(List<Conversation> c) {
adapter.setList(c);
adapter.notifyDataSetChanged();
}
And don't to forget to create setList(List<Conversation> c) method in your Adapter
I am still stuck with this issue, can anyone help. It seems that my problem is that I cant update the data list. I have tried every solution that I've searched for on google etc.. but half the time i'm not even sure that I'm doing the correct thing.
I've used the onResume() to call notifyDataSetChanged, it didn't work. I've tried putting a refresh method into the adapter which i then called in OnResume(). Again it didn't work. Some people suggest clearing the adpater (adapter.clear();) in onResume and then using the addAll() function to relist the data but nothing works.
There has to be a simple solution to this. I have literally been stuck on this for 2 days now. very frustrated.
Here's my Fragment code again...
enter code here
public class SavedAppFragment extends ListFragment {
private static final String TAG = "AppClicked"; //DEBUGGER
private ArrayList<App> mSavedApps;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Populate the ArrayList
mSavedApps = SavedAppData.get(getActivity()).getApps();
AppAdapter adapter = new AppAdapter(mSavedApps);
setListAdapter(adapter);
}
//LIST ITEM CLICKED: /*Control what happens when list item is clicked: I.E. Load up a quiz while putting an EXTRA key containg the package name of the App to be launhced should the user get the question correct */ #Override public void onListItemClick(ListView l, View v, int position,long id) { //Return the crime for the list item that was clicked App c = ((AppAdapter) getListAdapter()).getItem(position); Log.d(TAG, "was clicked");
//Start the Activity that will list the detail of the app
Intent i = new Intent(getActivity(), Quiz_Activity.class);
String name = c.getPackage();
i.putExtra("packagename", name);
startActivity(i);
}
private class AppAdapter extends ArrayAdapter {
private ArrayList<App> mSavedApps;
public AppAdapter(ArrayList<App> apps) {
super(getActivity(), 0, apps);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
//If we weren't given a view, inflate one
if (null == convertView) {
convertView = getActivity().getLayoutInflater().inflate(R.layout.list_item_app, null);
//((AppAdapter) getListAdapter()).notifyDataSetChanged();
}
((AppAdapter) getListAdapter()).notifyDataSetChanged();
//Configure the view for this crime
App c = getItem(position);
TextView nameTextView = (TextView) convertView.findViewById(R.id.app_name);
nameTextView.setText(c.getName());
// nameTextView.setText(applicationInfo.loadLabel(packageManager));
TextView packageTextView = (TextView) convertView.findViewById(R.id.app_package);
packageTextView.setText(c.getPackage());
CheckBox appCheckBox = (CheckBox) convertView.findViewById(R.id.app_checked);
appCheckBox.setChecked(c.isChecked());
//Return the view object to the ListView
return convertView;
}
}
}
THANKS!!!
When you return to Activity B, the previous Activity B hasn't been destroyed. Thus, it skips the onCreate. Move all of the stuff you want to make sure happens every time into the onResume. I think you want to make your Adapter a class variable (I'll call it mAdapter) in onCreate, and add code that will get data from the list directly. If you need to do something, put a "refresh" function in the adapter. I'm assuming you have a custom Adapter, because I've never heard of AppAdapter. If you don't, then extend AppAdapter and add that functionality. Thus, your onCreate should look like this:
mAdapter = new AppAdapter(mSavedApps);
setListAdapter(mAdapter);
Your onRefresh could update the data contained in the adapter by some new update function, like so:
mAdapter.update(SavedAppData.get(getActivity()).getApps());
My project consists of a single Activity so far that loads a GridView that is populated by an extended BaseAdapter.
Typically the view is refreshed by calling BaseAdapter.notifyDataSetChanged() from one of my OnClickListener objects.
My problem is that I need to start a timer each time the view is refreshed. I only want to do this when the view has been completely reloaded.
I can't seem to find a listener or method that I can override in either the View or Adapter APIs to perform this, although I presume there is one.
The closest I've found is BaseAdapter.registerDataSetObserver although I'm not sure this is what I'm looking for either.
Can anyone advise please?
Thanks
DataSetObserver won't provide the feature you're looking for. In your adapter try looking at getView() or ViewBinder.setViewBinder() (for the Simple...Adapter classes) once the last view is filled with data you'll be able to know, roughly, when its done.
I'd say your best bet would be to create an anon inner class from this class and add your timer logic in an extension of GridView:
class AdapterDataSetObserver extends DataSetObserver {
#Override
public void onChanged() {
}
#Override
public void onInvalidated() {
}
}
(You can access this member variable as it is not priveate):
/**
* Should be used by subclasses to listen to changes in the dataset
*/
AdapterDataSetObserver mDataSetObserver;
This is the method that you should override (inside gridview) (You may need to make some modifications as some of these member variables may be private - mDataSetObserver is not, however:
#Override
public void setAdapter(ListAdapter adapter) {
if (null != mAdapter) {
mAdapter.unregisterDataSetObserver(mDataSetObserver);
}
resetList();
mRecycler.clear();
mAdapter = adapter;
mOldSelectedPosition = INVALID_POSITION;
mOldSelectedRowId = INVALID_ROW_ID;
if (mAdapter != null) {
mOldItemCount = mItemCount;
mItemCount = mAdapter.getCount();
mDataChanged = true;
checkFocus();
mDataSetObserver = new AdapterDataSetObserver();
mAdapter.registerDataSetObserver(mDataSetObserver);
mRecycler.setViewTypeCount(mAdapter.getViewTypeCount());
int position;
if (mStackFromBottom) {
position = lookForSelectablePosition(mItemCount - 1, false);
} else {
position = lookForSelectablePosition(0, true);
}
setSelectedPositionInt(position);
setNextSelectedPositionInt(position);
checkSelectionChanged();
} else {
checkFocus();
// Nothing selected
checkSelectionChanged();
}
requestLayout();
}
Look for these two lines in the method above and extend your class here:
mDataSetObserver = new AdapterDataSetObserver();
mAdapter.registerDataSetObserver(mDataSetObserver);
I have list of checkboxes in list binded by Custom simpleCursorAdapter.
In my custom simpleCursorAdapter, I've overridden newView and bindView with my modifications.
I've managed somehow to do multichoice.
The wierd thing is, after I delete any item from my list, the first item's checkbox is being checked all of a sudden. How does that happen? How can I solve it?
My SimpleCursorAdapter class:
public class MyListCursorAdapter extends SimpleCursorAdapter
{
private Context context;
private int layout;
public MyCursorAdapter(Context context, int layout, Cursor c,
String[] from, int[] to)
{
super(context, layout, c, from, to);
this.context = context;
this.layout = layout;
}
#Override
public View newView(Context context, Cursor cursor, ViewGroup parent)
{
Cursor c = getCursor();
final LayoutInflater inflater = LayoutInflater.from(context);
View v = inflater.inflate(layout, parent, false);
CheckBox chkBoxBtn = (CheckBox) v.findViewById (R.id.deleteTwittChkBox);
if (chkBoxBtn != null)
{
chkBoxBtn.setChecked(false);
}
return v;
}
#Override
public void bindView(View v, Context context, Cursor c)
{
--binding view to my textsview in my items
//now it's the importat part:
CheckBox chkBoxBtn = (CheckBox) v.findViewById(R.id.deleteTwittChkBox);
if (chkBoxBtn != null)
{
chkBoxBtn.setId(Integer.valueOf(c.getString(c
.getColumnIndex(MyUsers.User._ID))));
chkBoxBtn.setOnClickListener(new OnItemClickListener(chkBoxBtn, v));
chkBoxBtn.setChecked(false);
}
}
//i couldnt find another way of doing this, but this is how i set listeners to my checkboxses
static ArrayList<String> checkedItemsList = new ArrayList<String>();
private class OnItemClickListener implements OnClickListener
{
private int mPosition;
private CheckBox chkBox;
OnItemClickListener(CheckBox mChkBox, View v)
{
chkBox = mChkBox;
chkBox.setChecked(false);
}
#Override
public void onClick(View v)
{
if (chkBox.isChecked())
{
checkedItemsList.add(String.valueOf(chkBox.getId()));
}
else
{
checkedItemsList.remove(String.valueOf(chkBox.getId()));
}
}
}
}
Here is the code part from the ListActivity class which describes the button that deletes the checked box items:
OnClickListener btListener = new OnClickListener()
{
public void onClick(View view)
{
// long[] items = listView.getCheckItemIds();
int x = 0;
Uri myUri = Uri
.parse("content://com.idan.datastorageprovider/users");
String where = "_id" + "=?";
//here i am tatking all checkboxes which ive added from the adapter class
ArrayList<String> checkedItemsList = MySimpleCursorAdapter.checkedItemsList;
for (String itemID : checkedItemsList)
{
getContentResolver()
.delete(myUri, where, new String[] { itemID});
checkedItemsList.remove(itemID);
}
}
};
I doubt that SimpleCursorAdapter is the right class to extend here.
Is the "checked" state connected to the data XML in any way? No? So you need your own custom adapter!
Basically all adapters have to implement a way to generate a view from a given element (more precisely an element position!). This will be called at any time where the list wants to display an element. Now, the trick it uses is to re-use formerly created list view elements that cannot be seen on screen any more! Thus: when you scroll your list down and an element disappears at the top, EXACTLY this view object will be re-used for the next appearing item.
So, when this method is called with a given "old" view that should be re-used, all contained elements will have to be set according the elements data. If a checkbox is part of this game, you will have to have a storage for the checked state! It is not sufficient to have a checkbox as there will be less checkbox objects as there are list elements!
SimpleCursorAdapters are there to - yeah - represent SIMPLE things. An XML describing data (images and text, as the documentation states). Because of this simplicity all you have to do here is provide a method to create NEW element view objects - you are not intercepting the re-use process AT ALL! It basically only knows how to put the data into an existing view object - but it is lacking the knowledge of how to handle checked/unchecked boxes!
Your solution: write your own BaseAdapter extension and do what has to be done: implement "getView" (and some other methods like getItem, getItemId and getCount). It's not hard at all!
This API Demo uses a BaseAdapter and the mExpanded state here is basically identical to your checkbox states!
Good luck!
You might need to call notifyDataSetChanged when you modify the data.
The problem is probably that you're calling setChecked from within the onItemClickListener. One hacky way around this is to do the following before and after you call setChecked from within your listener:
chkBox.setClickable(false);
chkBox.setChecked(false);
checkBox.setClickable(true);
This will prevent your onItemClickListener from getting called when you manually call setChecked.