Expression is not assignable error with CGRect

Question

I'm trying to create a CGRect property.

@property (nonatomic) CGRect myRect;

Then later on, I set the frame:

self.myRect = self.frame;
self.myRect.size.height = 10; // Error

I get an error saying "Expression is not assignable". Why do I get that? Can't I change the size of a CGRect?

Rajesh Maurya · Accepted Answer · 2015-06-24T08:30:30.060

1

Do it this way.

_myRect = self.frame;
_myRect.size.height = 10;

edited Jun 24 '15 at 08:30

answered Jun 24 '15 at 08:27

Rajesh Maurya

I can't create 1 that will be accessible throughout the class? – Jessica Jun 24 '15 at 08:28
Thanks!! That worked!! Why can't I use self instead? – Jessica Jun 24 '15 at 08:33
If it help make it accepted. Please check this answer for more clarification. http://stackoverflow.com/questions/5860755/how-to-gain-assignment-access-to-cgrect-elements-when-the-cgrect-is-an-instance – Rajesh Maurya Jun 24 '15 at 08:38
I was waiting for the timer to finish :) – Jessica Jun 24 '15 at 08:38

score 1 · Answer 2 · answered Jun 24 '15 at 08:43

self.myRect.size.height = 10 is equivalent to [ self myRect ].size.height = 10

You must read the CGRect property, modify it, then write it back:

CGRect r = [ self myRect ] ;
// modify r here
[ self setMyRect:r ] ;

or:

CGRect r = self.myRect ;
// modify r here
self.myRect = r ;

2 Answers2