Best Way to Refresh Adapter/ListView on Android

Question

My book, "Hello Android" gives this as a way of using a custom db helper, setting up a cursor, and then setting up an adapter as follows:

Cursor cursor
CustomDatabaseHelper test = new CustomDatabaseHelper(this);
try {
        cursor = getData();
        showData(cursor);
} finally {
        test.close();
}

With this however, everytime I need to refresh the data set, I need to keep running this block of code (which gets a bit difficult inside an onClick() for a button due to "this" not being available.

Is this the best way to refresh the data set, or should I look towards removing the .close and issue an adapter.notifyDataSetChanged()? If I do this, sometimes I get a force close as (and I can't remember at the moment) but sometimes it cannot Delete properly - I think this may be because the database is currently open and it tries to open again.

Should we also be declaring the variables for the Cursors, DatabaseHelpers and Adapter in the Class (outside of the OnCreate) so that they are accessible to all the functions?

I realise this is just poor programming at this stage, but Im trying to get some pointers as to the best way of doing things.

Just a sidenote: Things are a bit different if you use content providers and LoaderManager. See: http://stackoverflow.com/a/19657500/1087411 — Anderson, Apr 13 '14 at 11:55

score 104 · Answer 1 · edited Jul 05 '16 at 01:41

104

You should use adapter.notifyDataSetChanged(). What does the logs says when you use that?

edited Jul 05 '16 at 01:41

ThomasW

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answered Nov 16 '10 at 12:54

Macarse

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1

Thanks Macarse, That does work, but only if I don't do a .close on the database helper. I think also what happens if I don't do the .close, the system tries to open too many databases and falls over. Should the database be open across the lifecycle of the activity then? – Simon Nov 16 '10 at 13:14
You should use http://developer.android.com/reference/android/app/Activity.html#startManagingCursor(android.database.Cursor) to manage your cursor inside an Activity. – Macarse Nov 16 '10 at 21:07

score 17 · Answer 2 · edited Aug 31 '13 at 13:03

17

Simply add these code before setting Adapter it's working for me:

    listView.destroyDrawingCache();
    listView.setVisibility(ListView.INVISIBLE);
    listView.setVisibility(ListView.VISIBLE);

Or Directly you can use below method after change Data resource.

   adapter.notifyDataSetChanged()

edited Aug 31 '13 at 13:03

Stefano Munarini

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answered Sep 14 '11 at 13:23

sravan

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This does apply on Buttons as well : // Force refresh myButton.setVisibility(Button.INVISIBLE); myButton.setVisibility(Button.VISIBLE); – hornetbzz Sep 09 '12 at 01:47
1

for what purpose you have to refresh your button ? – sravan Sep 10 '12 at 05:44
after a filter and then its reverse is applied. – hornetbzz Sep 10 '12 at 07:56

score 15 · Answer 3 · answered Mar 31 '17 at 19:52

15

Best Way to Refresh Adapter/ListView on Android

Not only calling notifyDataSetChanged() will refresh the ListView data, setAdapter() must be called before to load the information correctly:

  listView.setAdapter(adapter);
  adapter.notifyDataSetChanged();

answered Mar 31 '17 at 19:52

Jorgesys

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if you use setAdaper, you dont need to use notifyDataSetChanged – Arda Kaplan Nov 03 '18 at 09:55

score 12 · Answer 4 · answered Dec 03 '10 at 18:00

12

Following code works perfect for me

EfficientAdapter adp = (EfficientAdapter) QuickList.getAdapter();
adp.UpdateDataList(EfficientAdapter.MY_DATA);
adp.notifyDataSetChanged();
QuickList.invalidateViews();
QuickList.scrollBy(0, 0);

answered Dec 03 '10 at 18:00

Hims

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Calling notifyDataSetChanged() was not sufficient for me. invalidateViews() instead works. – Luca Carlon Oct 12 '16 at 14:42

score 2 · Answer 5 · answered Aug 29 '16 at 10:10

2

adapter.notifyDataSetChanged();

answered Aug 29 '16 at 10:10

Dinesh Saini

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Please edit with more information. Code-only and "try this" answers are discouraged, because they contain no searchable content, and don't explain why someone should "try this". – abarisone Aug 29 '16 at 14:22
on Search you want to refresh adapter ? – Dinesh Saini Aug 30 '16 at 05:43

score 2 · Answer 6 · answered Oct 18 '18 at 02:44

If nothing works, just create the adapter instance again with the new set of results or the updated set of results. Then you can see the new view.

XYZAdapter adbXzy = new XYZAdapter(context, 0, listData);
xyzListView.setAdapter(adbXzy);

adbXzy.notifyDataSetChanged();

score 0 · Answer 7 · answered Mar 02 '16 at 12:45

0

If you are using LoaderManager try with this statement:

getLoaderManager().restartLoader(0, null, this);

answered Mar 02 '16 at 12:45

adev

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score 0 · Answer 8 · edited Sep 26 '16 at 00:12

Perhaps their problem is the moment when the search is made in the database. In his Fragment Override cycles of its Fragment.java to figure out just: try testing with the methods:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_x, container, false); //Your query and ListView code probably will be here
    Log.i("FragmentX", "Step OnCreateView");// Try with it
    return rootView; 
}

Try it similarly put Log.i ... "onStart" and "onResume".

Finally cut the code in "onCreate" e put it in "onStart" for example:

@Override
public void onStart(){
    super.onStart();
    Log.i("FragmentX","Step OnStart");
    dbManager = new DBManager(getContext());
    Cursor cursor = dbManager.getAllNames();
    listView = (ListView)getView().findViewById(R.id.lvNames);
    adapter = new CustomCursorAdapter(getContext(),cursor,0);// your adapter
    adapter.notifyDataSetChanged();
    listView.setAdapter(adapter);
}

score 0 · Answer 9 · edited Mar 23 '17 at 10:27

0

Just write in your Custom ArrayAdaper this code:

private List<Cart_items> customListviewList ;

refreshEvents(carts);

public void refreshEvents(List<Cart_items> events)
{
    this.customListviewList.clear();
    this.customListviewList.addAll(events);
    notifyDataSetChanged();
}

edited Mar 23 '17 at 10:27

Harsh Wardhan

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answered Mar 23 '17 at 08:39

SAOUD SALIH HASSAN

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score -4 · Answer 10 · answered Aug 29 '16 at 10:08

-4

just write in your Custom ArrayAdaper this code:

public void swapItems(ArrayList<Item> arrayList) {
    this.clear();
    this.addAll(arrayList);
}

answered Aug 29 '16 at 10:08

Yerassyl

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Best Way to Refresh Adapter/ListView on Android

10 Answers10