这是目标C中的保留周期吗？

Question

I've declared a property on my UICollectionViewCell like this:

@property (nonatomic, copy) void(^onSelection)(BOOL selected);

I override -setSelected: like this:

- (void)setSelected:(BOOL)selected {
    [super setSelected:selected];

    if (self.onSelection != NULL) {
        self.onSelection(selected);
    }
}

Then in -cellForItemAtIndexPath: i configure like this

cell.onSelection = ^(BOOL selected) {
    //the compiler is telling me this might be a retain cycle but i dont think so...
    cell.tintColor = [UIColor redColor];
};

Is this a retain cycle?

Thanks!

Answer 1

Yes it is. Instead you should use a weak+strong combo.

__weak typeof(cell) weakCell = cell;
cell.onSelection = ^(BOOL selected) {
    __strong typeof(weakCell) strongCell = weakCell;
    //the compiler is telling me this might be a retain cycle but i dont think so...
    strongCell.tintColor = [UIColor redColor];
};

In your particular case you don't even need this block because you can update cell in subclass inside of setSelected: or handle tableView:didSelectRowAtIndexPath: in your table view controller.