Unable to add window -- token null is not valid is your activity running

Question

I am trying to put a feature of a custom popup menu that shows up when the user clicks on the floating icons.

Floating icon code:

public class copy_actions_service extends Service
{
    ImageView copy_ImageView;
    WindowManager windowManager;
    WindowManager.LayoutParams layoutParams;

    @Override
    public IBinder onBind(Intent arg0)
    {
        // TODO Auto-generated method stub
        return null;
    }
    
    @Override
    
    public void onCreate()
    {
        windowManager=(WindowManager)getSystemService(WINDOW_SERVICE);
        
        copy_ImageView=new ImageView(this);
        copy_ImageView.setImageResource(R.drawable.ic_launcher);
        copy_ImageView.setAlpha(245);
        copy_ImageView.setOnClickListener(new OnClickListener()
        {
            
            @Override
            public void onClick(View arg0)
            {
                showCustomPopupMenu();
            }
        });
        
        layoutParams=new WindowManager.LayoutParams(
                WindowManager.LayoutParams.WRAP_CONTENT,
                WindowManager.LayoutParams.WRAP_CONTENT,
                WindowManager.LayoutParams.TYPE_PHONE,
                WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
                PixelFormat.TRANSLUCENT);
        
        layoutParams.gravity=Gravity.TOP|Gravity.CENTER;
        layoutParams.x=0;
        layoutParams.y=100;
        
        windowManager.addView(copy_ImageView, layoutParams);

    }
    
    private void showCustomPopupMenu()
    {
        LayoutInflater layoutInflater=(LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view=layoutInflater.inflate(R.layout.xxact_copy_popupmenu, null);
        
        PopupWindow popupWindow=new PopupWindow();
        popupWindow.setContentView(view);
        popupWindow.setWidth(LinearLayout.LayoutParams.WRAP_CONTENT);
        popupWindow.setHeight(LinearLayout.LayoutParams.WRAP_CONTENT);
        popupWindow.setFocusable(true);

        popupWindow.showAtLocation(view, Gravity.NO_GRAVITY, 0, 0);             
    }
}

The problem starts when I click on the float button app it stops and this error is shown:

11-23 02:18:58.217: E/AndroidRuntime(3231): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?

How can I show a popup menu with icons? Can someone help me with this?