How to refresh Android listview?

Question

How to refresh an Android ListView after adding/deleting dynamic data?

Answer 1

Consider you have passed a list to your adapter.
Use:

list.getAdapter().notifyDataSetChanged()

to update your list.

Answer 2

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..

Answer 3

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!!!

Answer 4

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;

}

Answer 5

The easiest is to just make a new Adaper and drop the old one:

myListView.setAdapter(new MyListAdapter(...));

Answer 6

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.