UIView setNeedsDisplay with NSThread/NSTimer

grzesiek · 07-07-2010, 01:06 PM

Hi!

I have UIView, which shows simple line chart (it's drawing in drawRect method with CGContext methods). I want refresh this chart between 5 seconds while UIView is visible. How can I do this? Could you show me very simple code example?

I'm asking for that, because when I'm using timer with [self setNeedsDisplay] my app cause crash sometimes (and debugger console is empty). I was trying call [self setNeedsDisplay] with [self performSelectorOnMainView....] and [NSThread detachNewThreadSelector..] and [self performSelector.. withObject... afterDelay...].. every time my app is crashing..

Sorry for my poor language.

Regards,
Greg

**JasonR** · 07-07-2010, 01:26 PM

You can only call UI methods from the main thread. Calling then from any other thread will crash. Look into performSelectorOnMainThread if you need to trigger the call from another thread.

grzesiek · 07-07-2010, 01:47 PM

So, I should use something like that: [self performSelectorOnMainThread:@selector(setNeedsDisp lay) withObject:nil waitUntilDone:YES] ? Can I use this in thread fired with same UIView?