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objective-cmethodscgrect

Calling a complicated method from another method in Objective C

I've seen many cases here where someone asks how to call one extremely simply-named method from another method, and gets a simple answer.

However, I have a CGRect method

- (void)drawRect:(CGRect)rect { /* code that draws circles */}

which successfully draws nmax circles for me. I also have a button method that successfully updates an "nmax" displayed on the screen. 

- (IBAction)changeIntValue:(id)sender {nmax=nmax+100;}

Only problem is that I want it to redraw the screen for me as well. I cannot for the life of me figure out, even after Ring some FM's, the syntax to "re-call" this rect down again in my changeIntValue method.

Any help greatly appreciated. While I'm typing, if anyone has a reference with exhaustive info on syntax, that would be helpful. References at developer.apple.com and most tutorials veer off into giving specific examples likeThisExample. I hand-wrote some notes off a youtube lecture which gave syntax, but lost the reference.

Solution

  • You can cause an item to redraw using 

    [view setNeedsDisplay];

    where view is obviously your view. This causes the view to be redrawn in the UI thread, and your view drawing code should then call your drawRect methods as appropriate.