public void onListItemClick(ListView parent, View v, int position, long id) {
    Toast.makeText(this,
        "You have selected " + lv_arr[position],
        Toast.LENGTH_SHORT).show();
}

<activity android:name=".WhiteListView"/>

@Override
    public void onListItemClick( ListView parent, View v, int position, long id)  {
        Intent lancon = new Intent(this, viewContact.class);
        //lancon.putExtra("id", id);
        //or
        c.moveToPosition(position);
        id = c.getInt(0);
        c.close();
        lancon.putExtra("id", id);
        this.startActivity(lancon);
        finish();
    }

this._id = this.getIntent().getLongExtra("id", 0);