DialogFragment

package com.example.motoharu.shoplist;

import android.app.*;
import android.content.*;
import android.os.*;
import android.view.*;



public class AlertEdit extends DialogFragment {

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
       AlertDialog.Builder bd = new AlertDialog.Builder(getActivity());
       LayoutInflater inflater = getActivity().getLayoutInflater();
       bd.setView(inflater.inflate(R.layout.alert, null))
               .setTitle("Edit")
               .setPositiveButton(R.string.save, new DialogInterface.OnClickListener() {
                   @Override
                   public void onClick(DialogInterface dialog, int which) {
                       ((MyActivity)getActivity()).doPositiveClick();
                   }
               })
                .setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        ((MyActivity)getActivity()).doNegativeClick();
                    }
                });

        return bd.create();
    }




}

EditDialog

import android.app.Activity;
import android.app.AlertDialog;
import android.app.DialogFragment;
import android.app.FragmentManager;
import android.app.Notification;
import android.content.DialogInterface;
import android.net.wifi.p2p.WifiP2pManager;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;

import java.util.ArrayList;


public class MyActivity extends Activity {
    public static ArrayList<String> goods;
    public ListView lw;
    public EditText edtxt;
    private int position;
    public AdapterView.AdapterContextMenuInfo info;
    ArrayAdapter<String> adapter;
    public static EditText alertEd;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);

         lw = (ListView) findViewById(R.id.listView);
         edtxt = (EditText) findViewById(R.id.editText);
        alertEd = (EditText) findViewById(R.id.alertEdit);


        goods = new ArrayList<String>();

        adapter  = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, goods);
        lw.setAdapter(adapter);

        lw.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> adapter, View v,
                                    int position, long id) {

            }
        });
        registerForContextMenu(lw);

        edtxt.setOnKeyListener(new View.OnKeyListener() {
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) {

                if (event.getAction()== KeyEvent.ACTION_DOWN) {
                    if (keyCode == KeyEvent.KEYCODE_ENTER) {
                        goods.add(0, edtxt.getText().toString());
                        adapter.notifyDataSetChanged();
                        edtxt.setText("");
                        return true;
                    }
                }
               return false;
            }
        });
        }

    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo info){
        super.onCreateContextMenu(menu, v, info);
        getMenuInflater().inflate(R.menu.actions, menu);

    }
    public boolean onContextItemSelected(MenuItem item) {

        position = (int) info.id;
        switch (item.getItemId()) {
            case R.id.cnt_mnu_delete:
                goods.remove(position);
                adapter.notifyDataSetChanged();
                return true;
            case R.id.cnt_mnu_edit:
                this.showDialog();


               /* AlertDialog.Builder alert = new AlertDialog.Builder(this);



// Set an EditText view to get user input
                final EditText input = new EditText(this);
                alert.setTitle("Edit");
                alert.setMessage("Change an item");
                alert.setView(input);

                alert.setPositiveButton("Save", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {
                        String value = input.getText().toString();
                        goods.set(position, value);
                        adapter.notifyDataSetChanged();
                        // Do something with value!
                    }
                });

                alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {
                       dialog.cancel();
                    }
                });

                alert.show();

*/
        }


        return super.onContextItemSelected(item);
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.my, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
public void doPositiveClick()
{
    info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
    position = (int)info.id;
    final EditText input = new EditText(this);
    String value = input.getText().toString();
    goods.set(position, value);
    adapter.notifyDataSetChanged();
}
    public void doNegativeClick()
    {

    }
public void showDialog()
{
    DialogFragment frag = new AlertEdit();
    frag.show(getFragmentManager(), "edit");
}
}