Question

I create a Context Menu for a ListView. On long-clicking an item in the ListView, a context menu with two options (Edit and Delete) will appear. My purpose is that when clicking Delete, only will the selected item in the ListView be removed from the list. But I don’t know why all the items in the list are removed when this is done.

Here below is my code lines. Can you please provide a little help? It would be nice if you could give instructions based on my code.

Thank you very much in advance.

public class HistoryView extends Activity {
private static final String HISTORY_TAG = "[AppName - HistoryView] ";
private ListView mLSTHistory = null;
private ArrayList<String> lstDict = null;
private ArrayList<Integer> lstId = null;
private ArrayAdapter<String> aptList = null;
private ArrayList<String> mWordHistory = null;
private SharedPreferences prefs;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.history);
    prefs = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());

    if (prefs.getBoolean("saveHistory", true))
    {
        String strHistory = prefs.getString("history", "");
        Log.i(HISTORY_TAG, "History loaded");
        if (strHistory != null && !strHistory.equals(""))
        {
            mWordHistory = new ArrayList<String>(Arrays.asList(strHistory.split(",")));
        }
        else
        {
            mWordHistory = new ArrayList<String>();
        }
    }
    else
    {
        mWordHistory = new ArrayList<String>();
    }

    Log.d(HISTORY_TAG,"mWordHistory = " + mWordHistory.size());

    if (lstDict == null)
    {
        lstDict = new ArrayList<String>();
        lstId = new ArrayList<Integer>();
        aptList = new ArrayAdapter<String>(getApplicationContext(),R.layout.customlist);
    }
    lstDict.clear();
    lstId.clear();
    aptList.clear();
    if (mWordHistory != null && mWordHistory.size() > 0)
    {
        try
        {
            for (int i=0; i < mWordHistory.size(); i++)
            {
                Log.i(HISTORY_TAG,"item = " + mWordHistory.get(i));
                String arrPart[] = mWordHistory.get(i).split("::");
                if (arrPart.length == 3)
                {
                    //Log.i(CONTENT_TAG, "loaded content " +arrPart.length + ", wordId = " + arrPart[1]);
                    //Log.i(CONTENT_TAG, "loaded 0");
                    lstDict.add(i,arrPart[0]);
                    //Log.i(CONTENT_TAG, "loaded 1");
                    lstId.add(i,Integer.parseInt(arrPart[1]));
                    //Log.i(CONTENT_TAG, "loaded 2");
                    aptList.add(arrPart[2]);
                }
                else
                {
                    Log.i(HISTORY_TAG,"Wrong entry: " + mWordHistory.get(i));
                }
            } 
        }
        catch (Exception ex)
        {
            Log.i(HISTORY_TAG,"Wrong entry found!");
        }
    }

    mLSTHistory = (ListView) findViewById(R.id.lstHistory); 
    registerForContextMenu(mLSTHistory);
    mLSTHistory.setAdapter(aptList);

    mLSTHistory.setOnItemClickListener(new AdapterView.OnItemClickListener() 
    {
        public void onItemClick(AdapterView<?> arg0, View v, int arg2, long arg3)
        {
            Intent i = new Intent();
            i.putExtra("dict", lstDict.get(arg2));
            i.putExtra("wordId", lstId.get(arg2));
            setResult(RESULT_OK,i);
            finish();
        }
    });
}

@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.context_menu, menu);
}
@Override
public boolean onContextItemSelected(MenuItem item) {
    AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
    switch (item.getItemId()) {
        case R.id.edit:
            editItem(info.id);
            return true;
        case R.id.delete:
            deleteItem(info.id);
            return true;
        default:
            return super.onContextItemSelected(item);
    }
    }
private void deleteItem(long id) {
    // TODO Auto-generated method stub
    mWordHistory.clear();
    aptList.clear();
    mLSTHistory.setAdapter(aptList);
    SharedPreferences.Editor editor = prefs.edit();
    editor.putString("history", "");
    editor.commit();
    setResult(RESULT_OK);
    finish();
    }
private void editItem(long id) {
    //Edit item...
    }
}

---

UPDATE:

Thanks to raju, it now works (selected item removed from the list). However, the selected item is not removed from SharedPreferences. That’s why it reappears when the the list is reloaded.

I use the following code lines to save items to SharedPreferences. Could anyone tell me how to update the SharedPreferences so that it reflects the change when items are removed from the list using raju’s code lines. Thank you very much indeed.

if (prefs.getBoolean("saveHistory", true) && mWordHistory != null && mWordHistory.size() >= 1)
        prefs =   PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        StringBuilder sbHistory = new StringBuilder();
        for (String item : mWordHistory)
        {
            sbHistory.append(item);
            sbHistory.append(",");

        String strHistory = sbHistory.substring(0, sbHistory.length()-1);
        SharedPreferences.Editor editor = prefs.edit();
        editor.putString("history", strHistory);
        editor.commit();
        }

Answer 1

aptList.clear();

this line clears adapter… so all the items are being deleted..
instead use

               aptlist.remove(//the selected item);

in place of this

   deleteItem(info.id);

put

  String content =getListView().getItemAtPosition(info.position);
   aptList.remove(content);
   aptList.notifyDataSetChanged();