Android - Creating a on click listener to a Button and a extended ImageView on the same activity

I have these things, in a activity i set a onTouchListener to my ImageDraw, that extends the ImageView class, with this listener I perform actions like zoom and pan with gestures

But in this activity i have a button to, but when a set the onClickListener to the button i get i NullPointerException.

Without setting the onClickListener everything works fine.

My ImageDraw class is:

public class ImageDraw extends ImageView{
private Paint   mPaint = new Paint();
List<Point> pts = new ArrayList<Point>() ;

public ImageDraw(Context context) {
    super(context);

}
//used to send the location of the points to draw on the screen
//must be called before every redraw to update the points on the screen
public void SetPointsToDraw(List<Point> pts)
{
    this.pts = pts;
}


public ImageDraw(Context context, AttributeSet attrs)
{
    super(context,attrs);
}
public ImageDraw(Context context, AttributeSet attrs, int defStyle)
{
    super(context, attrs, defStyle);
}

@Override
public void o开发者_Go百科nDraw(Canvas canvas)
{
    super.onDraw(canvas);

    Paint paintColor = mPaint;
    paintColor.setColor(Color.YELLOW);
    paintColor.setStrokeWidth(3);


    if(pts.size() > 0)
    {
        canvas.drawCircle(pts.get(0).x, pts.get(0).y, 7, paintColor);   
    }
    if (pts.size() > 1)
    {
        for (int i = 1 ; i < pts.size(); i++) {
            paintColor.setColor(Color.YELLOW);
            canvas.drawCircle(pts.get(i).x, pts.get(i).y, 7, paintColor);
            paintColor.setColor(Color.RED);
            canvas.drawLine(pts.get(i-1).x, pts.get(i-1).y, pts.get(i).x, pts.get(i).y, paintColor);
        }
    }


}

}

Edited:

Here is where i set the onClickListener to the button, and its here where te excpetion is throw. Exactly on the btnNew.SetOnTouchListener

        Button btnNew = (Button) findViewById(R.id.btnNew);
    try
    {
    btnNew.setOnTouchListener(new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {

            Intent intent = new Intent(getApplicationContext(), NewWaypoint.class);
            startActivity(intent);
            return false;
        }
    });
    }
    catch(Exception e)
    {
        String teste = e.toString();
    }

My best guess right now is that you don't set the content view in the activity. can you post your stack trace and activity code?

I've meet the similar question, but I found that I forget to setcontentView in the activity. Hope it can help you.