Try putting a short sleep into your onTouchEvent handler, about 16ms is good. If I remember correctly (from previous posts in this forum) your app is getting hammered by all the Touch events, they are coming much more frequently than the maximum possible screen refresh/redraw rate.
-- RichardC On Oct 18, 4:56 am, Dianne Hackborn <[email protected]> wrote: > The move event you receive contains as close as possible to the most recent > location (it is retrieved immediately before dispatching to the app). > You don't say how much lag you are seeing, so it is hard to offer advice -- > is it more laggy than in other standard parts of the UI like list views? Is > it the same? If it is the same, this is probably just a lower-level > characteristic of the device -- there can be a lot of filtering/processing > going on in the touch firmware to generate clean points, for example. > > If the lag you are seeing is worse than the rest of the UI, it most likely > is an issue in your app, unrelated to the simple dispatching code here. > Perhaps some part of the drawing is very slow, etc. You could try > profiling it to see what is going on. > > > > On Sat, Oct 17, 2009 at 8:04 PM, Matt Hall <[email protected]> wrote: > > > Hi everyone, > > > I noticed when developing on an HTC Magic (G2) that when moving your > > finger on the screen the location of the touch events trail your > > finger pretty significantly. To test this I wrote a very simple app > > that just draws a rectangle where you're touching. Even in this simple > > case the rectangle can trail the finger on screen by a fair amount. > > Here's the View that handles the touches and draws the rectangle: > > > public class TouchTestView extends View { > > private float x; > > private float y; > > private Paint paint = new Paint(); > > public static final int SIZE = 40; > > > public TouchTestView(Context context) { > > super(context); > > paint.setColor(Color.RED); > > } > > > �...@override > > public boolean onTouchEvent(MotionEvent event) { > > switch (event.getAction()) { > > case MotionEvent.ACTION_DOWN: > > x = event.getX(); > > y = event.getY(); > > invalidate(); > > return true; > > case MotionEvent.ACTION_MOVE: > > x = event.getX(); > > y = event.getY(); > > invalidate(); > > return true; > > case MotionEvent.ACTION_UP: > > x = -1; > > y = -1; > > invalidate(); > > return true; > > } > > return super.onTouchEvent(event); > > } > > > �...@override > > protected void onDraw(Canvas canvas) { > > canvas.drawRect(x - SIZE, y - SIZE, x + SIZE, y + SIZE, > > paint); > > } > > } > > > So my question is: Is there a significant built in time delay between > > the generation of the touch event and it's reception in the running > > activity? If so, is there any tricks or methods to get those events in > > a faster or more direct way? In our application the delay is causing > > some pretty unfortunate performance results. > > > Thanks for any advice or help, > > Matt > > -- > Dianne Hackborn > Android framework engineer > [email protected] > > Note: please don't send private questions to me, as I don't have time to > provide private support, and so won't reply to such e-mails. All such > questions should be posted on public forums, where I and others can see and > answer them. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~----------~----~----~----~------~----~------~--~---
