Cocoa memory management
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by silvio
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Published on 2010-06-17T17:20:01Z
Indexed on
2010/06/17
17:23 UTC
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At various points during my application's workflow, I need so show a view. That view is quite memory intensive, so I want it to be deallocated when it gets discarded by the user. So, I wrote the following code:
- (MyView *)myView {
if (myView != nil)
return myView;
myView = [[UIView alloc] initWithFrame:CGRectZero]; // allocate memory if necessary.
// further init here
return myView;
}
- (void)discardView {
[myView discard]; // the discard methods puts the view offscreen.
[myView release]; // free memory!
}
- (void)showView {
view = [self myView];
// more code that puts the view onscreen.
}
Unfortunately, this methods only works the first time. Subsequent requests to put the view onscreen result in "message sent to deallocated instance"
errors. Apparently, a deallocated instance isn't the same thing as nil. I thought about putting an additional line after [myView release]
that reads myView = nil
. However, that could result in errors (any calls to myView
after that line would probably yield errors).
So, how can I solve this problem?
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