how to implement UIView method in ANSI-C++?

Question

I have something like this:

// main.m
@interface MYView : UIView { @public int counter; } @end;
@implementation MYView 
- (void)drawRect:(CGRect)rect {
}
@end

now I would like to remove drawRect method (or any other method) from implementation here, and move it to C++ file utility.cpp.

The reason why I need this, is that I must use some C++ library, that will not compile in Objective-C++. And I need to use that library intensively so that just switching back and forth is not convenient.

I know I can simly do this:

- (void)drawRect:(CGRect)rect {
    call_cpp_function(rect);
}

but maybe I can just completely define the method in c++? Something like this:

void __magic_declaration__ MYView::drawRect(CPPTYPE(CGRect))
// note, this line is completely my own imagination, this is just to illustrate what I want.

The reason why I need this, is that I must use some C++ library, that will not compile in Objective-C++. — exebook, Apr 29 '13 at 08:37
Sorry, I got that from your question. Why are you drawing with C++ code (or is drawing only one simple example)? — David Rönnqvist, Apr 29 '13 at 08:40
Yes, I need to hook up many methods and callbacks to something like interpreted language written in C++. — exebook, Apr 29 '13 at 08:49

score 3 · Accepted Answer · edited May 23 '17 at 10:25

3

It is possible, if not exactly what you'd call pleasant. See this answer in which a view is constructed and drawn in pure C.

edited May 23 '17 at 10:25

Community

1
1

answered Apr 29 '13 at 09:20

Simon

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Hey look, it's my answer! You beat me to it, hah. – Richard J. Ross III Apr 30 '13 at 03:31
Yes I know it's yours. You're world famous now for going to deep roots) – exebook Apr 30 '13 at 03:37

score 2 · Answer 2 · answered Apr 29 '13 at 08:41

You can't do this. The closest you can get is calling C++ code from an ObjC method as you mentioned.

Technically you might be able to hack something up that adds the method dynamically using the ObjC runtime API, but that will be much clunkier, harder, and slower.

how to implement UIView method in ANSI-C++?

2 Answers2