Convert Arraylist to Array, data of Arraylist is of custom class type

Question

I have retrieved data from database and added to Arraylist using a class called AddDetails. In AddDetails class I am assigning all values. Then I have sent that ArrayList to activity class where I need to display that data in ListView. Now while copying data from ArrayList to Array I am getting error like class not found or while displaying on list view it is just showing some garbage value.

The code is as follows:

 private class SearchTask extends AsyncTask<Void, Void, Void>{
@Override
   protected Void doInBackground(Void... arg0) {
    // TODO Auto-generated method stub

     DatabaseHandler db = new DatabaseHandler();          

     String Place = etSearch.getText().toString();
     AddDetails details = new AddDetails(Place);
     alSearchResult = db.searchResultByPlace(details);
     arrStr = new String[alSearchResult.size()];

     try
     {
    arrStr = (String[]) alSearchResult.toArray();               
       ArrayAdapter<String> adapter = new ArrayAdapter<String>(SearchActivity.this,           android.R.layout.simple_list_item_multiple_choice, arrStr);

    lsSearchResult.setAdapter(adapter);
      }

      catch(Exception e)
      {
        Log.e("Error:" + e.toString());
      }


    return null;
}





 protected ArrayList<AddDetails> searchResultByPlace(AddDetails details)
{
ArrayList<AddDetails> alSearchData = null;
try
{
     String place = details.getPlace();

      Cursor c = mDataBase.rawQuery("SELECT * FROM " + ESTATE_DETAILS + " WHERE " +           strSearchType + " =  " + "'" + place + "'", null);
    c.moveToFirst();
    if(c.getCount() > 0)
    {
     alSearchData = new ArrayList<AddDetails>();
    if (c.moveToFirst()) 
    {
    do {
        details = new AddDetails();  
                    details.setID(Integer.parseInt(c.getString(0)));
            details.setPlace(c.getString(1));                        
                    details.setArea(c.getString(2));
            details.setType(c.getString(3));
            details.setPhoneNumber(c.getString(4));                                                                                                                                 

         // Adding contact to list
        alSearchData.add(details);
    } while (c.moveToNext());
   }

}

c.close();
}
catch(SQLException e)
{
Log.e("Error:", e.toString());
}

return alSearchData;

}

you can use the arraylist to display data in listview why do you need to convert arraylist to array? — Raghunandan
– Raghunandan, Commented Jun 13, 2013 at 7:19
what are you convert into array..?? just use that arraylist for listview.. — Sagar Maiyad
– Sagar Maiyad, Commented Jun 13, 2013 at 7:20
"it is just showing some garbage value." Did you override toString method in the AddDetails class ? — Alexis C.
– Alexis C., Commented Jun 13, 2013 at 7:21
when I try to display directly from Arraylist (See my code in Blackbelt's answer) it is showing com.example.realestate.AddDetails@40e253d8 data details are coming from AddDetails class. — Prax
– Prax, Commented Jun 13, 2013 at 9:11

Blackbelt · Accepted Answer · 2013-06-13 07:23:21Z

1

change

   arrStr = (String[]) alSearchResult.toArray();

with

   arrStr = alSearchResult.toArray(new String[0]);

answered Jun 13, 2013 at 7:23

Blackbelt

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3 Comments

Raghunandan Over a year ago

this lsSearchResult.setAdapter(adapter) in doInbackground should be moved to onpostExecute()

Prax Over a year ago

No use blackbelt, getting java.lang.ArrayStoreException: source[0] of type com.example.realestate.AddDetails cannot be stored in destination array of type java.lang.String[]

Prax Over a year ago

In some example I saw that, so just tried to convert into String array. Now tried to assign arraylist to list ArrayAdapter<AddDetails> adapter = new ArrayAdapter<AddDetails>(SearchActivity.this, android.R.layout.simple_list_item_1,alSearchResult); lsSearchResult.setAdapter(adapter); ********** It is displaying com.example.realestate.AddDetails@40e253d8 in list view

Chirag Jain · Accepted Answer · 2013-06-13 07:32:22Z

1

Please do not access your listView lsSearchResult in background thread. Pass your result to onPostExecute().

Try to use following Code :

private class SearchTask extends AsyncTask<Void, Void, ArrayList<String>>{
@Override
   protected ArrayList<String> doInBackground(Void... arg0) {

     DatabaseHandler db = new DatabaseHandler();          

     String Place = etSearch.getText().toString();
     AddDetails details = new AddDetails(Place);
     alSearchResult = db.searchResultByPlace(details);

     return alSearchResult;
}

protected void onPostExecute(ArrayList<String> result) {
     ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(SearchActivity.this,android.R.layout.simple_list_item_1, result);
     lsSearchResult.setAdapter(arrayAdapter); 
}

answered Jun 13, 2013 at 7:32

Chirag Jain

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2 Comments

Prax Over a year ago

The value is coming but not able to display

Chirag Jain Over a year ago

are you getting some type of error or it is just not showing anything ?

Aashish Bhatnagar · Accepted Answer · 2013-06-13 07:23:11Z

0

ArrayList<String> stock_list = new ArrayList<String>();
    stock_list.add("stock1");
    stock_list.add("stock2");
    String[] stockArr = new String[stock_list.size()];
    stockArr = stock_list.toArray(stockArr);
    for(String s : stockArr)
        System.out.println(s);

this is helpful for arraylist to array conversion also you can use arraylist directly with the arrayadapter no need to convert it to array

answered Jun 13, 2013 at 7:23

Aashish Bhatnagar

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