Question

I have a UIViewController that should lazily load a view and then keep it in memory as it’s re-used quite often until e.g. a memory warning occurs or I want to clean it for some other reason. In order to achieve the lazy loading, I’ve overwritten the default getter. Here’s my code:

@interface MyController {
    MyView *_myView;
}
@property(nonatomic, retain) MyView *myView;
@end

@implementation MyController
@synthesize myView = _myView;
- (MyView *)myView {
    if(_myView == nil) {
        _myView = [[MyView alloc] init];
        // some more initialization
    }
    return _myView;
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // the main part of my interest, freeing myView again
    self.myView = nil;
}
@end

Now my question is basically: Is it still correct to release myView like I did in - (void)didReceiveMemoryWarning or would I have to [_myView release]; _myView = nil; or even something completely different?

Also, is this generally the correct way of using lazy initialization or should I improve something here in general?

Answer 1

Your statement for releasing the memory is absolutely correct and there is no difference between two.

self.myView = nil;

In this case the setter method for myView property will be called and similar to as below.

-(void) setMyView:(MyView*) aMyView {
   [myView release];
   myView = aMyView;
}

for the lazy loading … I guess -(void)viewDidDisappear for releasing the views and others memory related stuff and -(void) loadview to recreate them again