CODEWITHSUNDEEP
cocoansviewnstimerappkit
supersurabbit
supersurabbit

Reputation: 441

NSTimer no effect...?

I tried to call [self setNeedsDisplay:YES] in a NSTimer selector in order to trigger the drawRect method.

At first, I put the NSTimer init code in a button func:

-(IBAction)buttonPush:(id)sender
{
   myTimer = [NSTimer scheduledTimerWithTimeInterval:1.0
    target:self
  selector:@selector(myTimerAction:)
  userInfo:nil
  repeats:YES];
}

-(void)myTimerAction:(NSTimer *) timer
{  
[self setNeedsDisplay:YES];
}

The "setNeedsDisplay" is called normally but the code inside the drawRect is never called:

- (void)drawRect:(NSRect)dirtyRect 
{
NSLog(@"drawRect");
}

Then I tried to move the NSTimer init code to "- (id)initWithFrame:(NSRect)frame", then everything works just fine. (the drawRect is called correctly every 1 sec).

What's the difference between the two methods above? What should I do if I want to trigger the Timer in a button?

Upvotes: 1

Views: 635

Answers (2)

ThomasW
ThomasW

Reputation: 17317

Since it works when you use initWithFrame:, the problem is probably that buttonPush: isn't hooked up correctly. Try setting a breakpoint in buttonPush: an see if it is actually called when you click the button.

Upvotes: 0

ettore
ettore

Reputation: 688

Just wondering, in what class does that code reside? I would assume the buttonPush: action is inside a controller, correct?

If so, then you should have:

-(void)myTimerAction:(NSTimer *) timer
{
  [[self view] setNeedsDisplay:YES];
}

because setNeedsDisplay: is a method of NSView, not NSViewController.

(BTW probably the reason why it works if you put it inside initWithFrame: is because that one is a NSView initializer: I'm guessing that when you move the code there you are also moving the myTimerAction: method, which then has "self" referring correctly to the view.)

Upvotes: 1

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