Как использовать DatePickerDialog в BaseAdapter

Я работаю с классом BaseAdapter . Я хочу отобразить в нем DatePickerDialog . Когда я использую showDialog (DATE_DIALOG_ID); , я получаю сообщение об ошибке.

Пожалуйста, объясните мне это.

пакет com.OrganisemeePhone.adapter;

import java.util.ArrayList;
import java.util.Vector;

import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.provider.OpenableColumns;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.DatePicker;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.CompoundButton.OnCheckedChangeListener;




public class TaskFilterAdapter extends BaseAdapter {
    String date, month, year,setdueDate;
    //int dateFormat;
    DatePickerDialog.OnDateSetListener dateListener;

    int myYear, myMonth, myDay;
    int dateFormat;
    int starcount=0;

    public TaskFilterAdapter datedialog;

    viewholder holder;
    LayoutInflater inflator;
    ArrayList<Integer> taskId = new ArrayList<Integer>();
    ArrayList<String> task = new ArrayList<String>();
    ArrayList<String> dueDate = new ArrayList<String>();
    ArrayList<Integer> priority = new ArrayList<Integer>();
    static final int DATE_DIALOG_ID = 0;
    Vector<Boolean> VectorCheckChange = new  Vector<Boolean>(); 
    Vector<Object> taskrow = new Vector<Object>();  

    static int pos;
    Context context;
    private boolean isdaymonth;
    public TaskFilterAdapter(Context context,ArrayList<Integer> taskId, ArrayList<String> task, ArrayList<Integer> priority, ArrayList<String> duedate) {
        super();

        inflator = LayoutInflater.from(context);
        this.taskId = taskId;
        this.context=context;

        this.task = task;
        this.dueDate = duedate;
        this.priority = priority;

        //dateFormat=LoginActivity.db.getdateformat();
        getDateFormate();
        dateFormat=LoginActivity.db.getdateformat();
        getDateFormate();
        for(int i=0; i<task.size(); i++)
        {
            VectorCheckChange.add(false);
        }
    }


    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return task.size();
    }

    @Override
    public Object getItem(int arg0) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public long getItemId(int arg0) {
        // TODO Auto-generated method stub
        return 0;
    }


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

        if(convertView==null)
        {
            holder = new  viewholder();
            convertView = inflator.inflate(R.layout.task_row, null);
            holder.task = (TextView)convertView.findViewById(R.id.task_row_text);
            holder.date = (TextView)convertView.findViewById(R.id.task_row_date_text);
            holder.star = (ImageView)convertView.findViewById(R.id.task_row_star);
            holder.chk = (CheckBox)convertView.findViewById(R.id.task_row_check_box);

            holder.task.setOnClickListener(new Clicker());
            holder.chk.setOnCheckedChangeListener(new Checker());
            holder.star.setOnClickListener(new Clicker());
            holder.date.setOnClickListener(new Clicker());

            setviewAsSettings();

            setviewAsSettings();


            convertView.setTag(holder);


            }
        else
        {
            holder=(viewholder)convertView.getTag();
        }


        pos = position;

        /****************** Set Task *************************/

        holder.task.setText(task.get(position));
        holder.task.setTag(position);
        holder.star.setTag(position);
        holder.date.setTag(position);



        /***************** Set Duedate ***********************/

        setdueDate = dueDate.get(position);

        month = setdueDate.substring(5, 7);
        date = setdueDate.substring(8, 10);



        if (!date.equals("00"))
        {
            if (isdaymonth) 
            if (isdaymonth)
            {
                holder.date.setText(date + "." + month + ".");
                Log.d("taskList Adapter"," date formate day month ");

            } 
            else 
            {
                holder.date.setText(month + "." + date + ".");
                Log.d("taskList Adapter"," date formate month  day");

            }
        } 
        else
        {
            holder.date.setText("");
        }



        /***************** Set Priority ***********************/


                if (priority.get(position).equals(-1) || priority.get(position).equals(0)|| priority.get(position).equals(3)) 
                {

                    holder.star.setBackgroundDrawable(context.getResources().getDrawable(R.drawable.star_low));

                } 
                else if (priority.get(position).equals(2)) 
                {

                    holder.star.setBackgroundDrawable(context.getResources().getDrawable(R.drawable.star_med));
                }
                else if (priority.get(position).equals(1)) 
                {

                    holder.star.setBackgroundDrawable(context.getResources().getDrawable(R.drawable.star_high));
                }




        /******************* Set tag in checkBox ******************************/

        holder.chk.setTag(position);

        if(VectorCheckChange.get(position))
        {
            holder.chk.setChecked(true);
            holder.task.setPaintFlags(holder.task.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
            holder.task.setTextColor(Color.parseColor("#848484"));
            holder.date.setPaintFlags(holder.task.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
            holder.date.setTextColor(Color.parseColor("#848484"));
            holder.task.setClickable(false);
            holder.task.setEnabled(false);
        }
        else
        {
            holder.chk.setChecked(false);
            holder.task.setPaintFlags(holder.task.getPaintFlags() & ~ Paint.STRIKE_THRU_TEXT_FLAG);
            holder.task.setTextColor(Color.parseColor("#000000"));
            holder.date.setPaintFlags(holder.task.getPaintFlags() & ~ Paint.STRIKE_THRU_TEXT_FLAG);
            holder.date.setTextColor(Color.parseColor("#000000"));
            holder.task.setClickable(true);
            holder.task.setEnabled(true);
        }


        return convertView;
    }
    // updates by nilesh
    public void setviewAsSettings(){
        //check for task setting
        SharedPreferences startup_pref = 
            PreferenceManager.getDefaultSharedPreferences(context);

        Boolean viewpriority=startup_pref.getBoolean("viewpriority", true);
        Boolean viewduedate=startup_pref.getBoolean("viewduedate", true);

            if(!viewpriority){
                holder.star.setVisibility(View.INVISIBLE);
            }               
            if(!viewduedate){
                holder.date.setVisibility(View.INVISIBLE);
            }
        //check for task setting completed
    }

    public class viewholder
    {
        TextView task,date;
        ImageView star;
        CheckBox chk;

    }


    public class Clicker implements OnClickListener
    {


        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub


            int position=(Integer)v.getTag();
            int setPriority = 0;

        if(v.getId() ==  holder.date.getId())
        {


            Log.i("Date Dialog Picker", "Click Date..................... ");

            ((Activity)context).showDialog(DATE_DIALOG_ID); 

        //.showDialog(DATE_DIALOG_ID);


            //.showDialog(DATE_DIALOG_ID);



            }
        dateListener =  new DatePickerDialog.OnDateSetListener() {

            @Override
            public void onDateSet(DatePicker view, int yr, int monthOfYear,
                    int dayOfMonth) {
                // TODO Auto-generated method stub
                myYear = yr;
                myMonth = monthOfYear;
                myDay = dayOfMonth;

                }

            };  



        if(v.getId() == holder.task.getId())
        {
            Intent display_int= new Intent(context, DisplyTaskActivity.class);
            display_int.putExtra(constantcode.TASK_ID,taskId.get(position));
            v.getContext().startActivity(display_int);

            Log.i("TaskList Adapter", "Task ....position...... "+holder.star.getTag());
        }


            if(v.getId() == holder.star.getId())
            {

                 if (priority.get(position).equals(-1) || priority.get(position).equals(0) || priority.get(position).equals(3)) 
                   {
                     priority.set(position, 2);
                     setPriority = 2;

                    holder.star.setBackgroundDrawable(context.getResources().getDrawable(R.drawable.star_low));

                    Log.d("TaskList Adapter", "----- Grey ----");
                   } 
                   else if (priority.get(position).equals(2)) 
                   {
                       priority.set(position, 1);
                       setPriority = 1;

                    holder.star.setBackgroundDrawable(context.getResources().getDrawable(R.drawable.star_med));

                    Log.d("TaskList Adapter", "----- Yellow ----");
                   }
                   else if (priority.get(position).equals(1)) 
                   {
                       priority.set(position, 0);
                       setPriority = 0;

                    holder.star.setBackgroundDrawable(context.getResources().getDrawable(R.drawable.star_high));

                    Log.d("TaskList Adapter", "----- Orange ----");
                   }


                  String  updateQuery = "update tbl_tasks set priority =" + setPriority + " where taskId="+ taskId.get(position);
                  LoginActivity.db.execNonQuery(updateQuery);


                   taskrow = LoginActivity.db.getTaskRow(taskId.get(position));

                    if(taskrow.get(2).toString().contains("'"))
                    {
                        taskrow.set(2, taskrow.get(2).toString().replace("'", "''"));
                    }

                    String insertQuery = "insert into tbl_update_tasks(taskId,listId,description,priority,dueDate,reminderId,senderId,receiverId,taskCategoryType,fadeDate,assignedId)values("+ taskrow.get(0) + ","+ taskrow.get(1)+ ",'"+ taskrow.get(2)+ "',"+ taskrow.get(3)+ ",'"+ taskrow.get(4)+ "',"+ taskrow.get(5)+ ","+ taskrow.get(6)+ ","+ taskrow.get(7)+ ",'"+ taskrow.get(8)+ "','"+ taskrow.get(9)+ "',"+ taskrow.get(10)+ ");";
                    LoginActivity.db.execNonQuery(insertQuery);
                   notifyDataSetChanged();
            }

                //Log.w("taskfilterAdapter","position....... "+v.getTag());
        }


    }

      Dialog onCreateDialog(int id){
            switch(id) {
            case DATE_DIALOG_ID:

                return new DatePickerDialog(this.context, dateListener, myYear, myMonth,myDay);

            }

            return null;

        }

    /* public class datedialogclicker extends Activity
    {


        @Override
        protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState);



            holder.date.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub

                    Log.v("New Class....", "Click OnClick.....");
                    showDialog(DATE_DIALOG_ID); 
                }

            });

            dateListener =  new DatePickerDialog.OnDateSetListener() {

                @Override
                public void onDateSet(DatePicker view, int yr, int monthOfYear,
                        int dayOfMonth) {
                    // TODO Auto-generated method stub
                    myYear = yr;
                    myMonth = monthOfYear;
                    myDay = dayOfMonth;

                    }

                };  



        }
         protected Dialog onCreateDialog(int id){
                switch(id) {
                case DATE_DIALOG_ID:

                    return new DatePickerDialog(context, dateListener, myYear, myMonth,myDay);

                }

                return null;

            }
    }*/

    public class Checker implements OnCheckedChangeListener
    {

        @Override
        public void onCheckedChanged(CompoundButton buttonView,
                boolean isChecked) {
            // TODO Auto-generated method stub

            int posi=(Integer)buttonView.getTag();

            if(isChecked)
            {
                VectorCheckChange.set(posi, true);              
            }
            else
            {
                VectorCheckChange.set(posi, false);
            }

            notifyDataSetChanged();


        }

    }
    // update by nilesh
    public void getDateFormate() {

        // Get the app's shared preferences
        SharedPreferences startup_pref = PreferenceManager
                .getDefaultSharedPreferences(context);

        // Get the value for the run counter
        isdaymonth = startup_pref.getBoolean(constantcode.ISDAYMONTH, true);
    }


}