Updating the List View When the Adapter Data Changes

Updating the list view when the adapter data changes

substitute:

mMyListView.invalidate();

for:

((BaseAdapter) mMyListView.getAdapter()).notifyDataSetChanged(); 

If that doesnt work, refer to this thread:
Android List view refresh

Updating the list view when the adapter data changes, in visual-studio android sdk

The problem is that tables instance (in c# section) is the one that gets updated but TableItemAdapter keeps a separate List internally and that's the one that should get updated instead.

Then NotifyDataSetChanged() will work! So...

My custom adapter

public class TableItemAdapter : BaseAdapter<Table>
{
    List<Table> items;
    ...
    public void Update(IEnumerable<Table> tables)
    {
        items.Clear();
        items.AddRange(aItems);
        NotifyDataSetChanged();
    }
}

c#

...
tables.Add(new Table() { Name = "Table A1" });
lvAdapter.Update(tables); // <-- call this everytime tables change

The code can be optimized, so that only one list of objects is used, by adding a method in the custom adapter to return its List<Table> items and using that instead of creating another List for tables.

How to refresh Android listview?

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.

ListView adapter data change without ListView being notified

You have to do all your updating of Adapter data on the UI thread so the synchronized block isn't necessary. It's also useless since your synchronizing on the AsyncTask which is created new each time it's executed.

Another problem is that you are calling notifyDataSetChanged external to the Adapter. You should call it at the end of your setListItems method. That shouldn't be causing errors though since it's being executed on the UI thread but it should not be called in that way.

You should make sure that your getReports method is not modifying the backing store of the Adapter in any way. Since it is running on a separate thread it cannot modify anything the Adapter has access too. Even if it's protected by locks. What you need to do is in your doInBackground method is generate the list of updates or a new list, etc., and pass that into onPostExecute which then commits the new data to the Adapter on the UI thread. So, if your getReports function is changing report_list and your Adapter has a reference to report_list you are doing it wrong. getReports must create a new report_list and then pass that back to your Adapter when it's finished creating it on the UI thread.

To reiterate, you can only modify data the Adapter and subsequently the ListView has access too on the UI thread. Using synchronization/locks does not change this requirement.

Updating background of ListView Items when Adapter data changes

You have to update the cursor using adapter.changeCursor when data changes. See this answer: https://stackoverflow.com/a/1986071/198996

Refresh List View (Custom adapter)

public View getView(int position, View convertView, ViewGroup parent) {

View row = inflater.inflate(R.layout.no_icon_list_row,parent,false);

return row;
   } 
} 

not right.you can modify below:

public View getView(int position, View convertView, ViewGroup parent) {

if(convertView == null){
      convertView = inflater.inflate(R.layout.no_icon_list_row,parent,false);
}

TextView myTitle = (TextView) convertView.findViewById (R.id.noIconListTitles);

return convertView, 
   } 

last. if you want refresh data just invoke adapter.notifyDataSetChanged.Hope help you.

How to update ListView after updating database?

Change following code:

public class SettingsActivity extends AppCompatActivity {
private Context context;
private DogDatabaseHelper dbHelper;
private ListView mListView;
private ArrayList<String> names = new ArrayList<String>();
@Override
public void onCreate(Bundle savedInstance){
    super.onCreate(savedInstance);
    setContentView(R.layout.settings);
    mListView = (ListView)findViewById(R.id.listforall);
    context = this;

    DogDatabaseHelper dbHelper = new DogDatabaseHelper(getApplicationContext());
    SQLiteDatabase db = dbHelper.getWritableDatabase();
    Cursor cursor = db.rawQuery("select name from dog",null);
    int count = cursor.getColumnIndex("name");
    if(cursor.moveToFirst()){

        do{
            names.add(cursor.getString(cursor.getColumnIndex("name")));
        }while (cursor.moveToNext());
        AdapterForNames namesAdapter = new AdapterForNames(this,names);
        namesAdapter.notifyDataSetChanged();
        mListView.setAdapter(namesAdapter);

        mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
                Intent intent = new Intent(SettingsActivity.this,SetupActivity.class);
                intent.putExtra("name",names.get(position));
                startActivity(intent);
            }
        });
    }
}

With below code:

public class SettingsActivity extends AppCompatActivity {
    private Context context;
    private DogDatabaseHelper dbHelper;
    private ListView mListView;
    private ArrayList<String> names = new ArrayList<String>();
    @Override
    public void onCreate(Bundle savedInstance){
        super.onCreate(savedInstance);
        setContentView(R.layout.settings);
        context = this;
        AdapterForNames namesAdapter = new AdapterForNames(this,names);
        mListView = (ListView)findViewById(R.id.listforall);
        mListView.setAdapter(namesAdapter);
        mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
                Intent intent = new Intent(SettingsActivity.this,SetupActivity.class);
                intent.putExtra("name",names.get(position));
                startActivity(intent);
            }
        });

        DogDatabaseHelper dbHelper = new DogDatabaseHelper(getApplicationContext());
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        Cursor cursor = db.rawQuery("select name from dog",null);
        int count = cursor.getColumnIndex("name");
        if(cursor.moveToFirst()){
            do{
                names.add(cursor.getString(cursor.getColumnIndex("name")));
                namesAdapter.notifyDataSetChanged();
            } while (cursor.moveToNext());
        }
    }

Hope it helps!

How to refresh ListView custom adapter data from the event listener that is in the adapter in Android?

I got the answer, actually it is too simple. What I need to do is just add this code inside the click listener of done button in the custom adapter.

This is the click listener of the doneBtn in custom adapter:

doneBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dbHelper.markAsDone(values.get(position).getId());
                //How can I update the listview items here ?
                if(values!=null)
                {
                    Task oldTask = values.get(position);
                    oldTask.setDone(Boolean.TRUE);
                    values.set(position,oldTask);
                    notifyDataSetChanged();
                }

            }
        });

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