Prevent NSRangeException in subarrayWithRange
I have this code which allows me to pa开发者_StackOverflowss in an index, and selectively retrieve, a number of images in an array for a certain range length - depending on orientation.
When in portrait the range should be be 20 items per index, and i have 43 items altogether. However when i pass in the last index, i get an out of range exception for index 59 beyond bounds of [0..42].
NSArray *tempArray = [self imageData];
UIDeviceOrientation devOr = [[UIDevice currentDevice] orientation];
int kItemsPerView;
if (UIDeviceOrientationIsPortrait(devOr)) {
kItemsPerView = 20;
}else {
kItemsPerView = 14;
}
NSRange rangeForView = NSMakeRange( index * kItemsPerView, kItemsPerView );
NSArray *subArray = [[tempArray subarrayWithRange:rangeForView] retain];
NSMutableArray *imagesForView = [NSMutableArray arrayWithArray:subArray];
[subArray release];
return imagesForView;
How can i prevent this?
Thanks.
if ((index * kItemsPerView + kItemsPerView) >= tempArray.count)
rangeForView = NSMakeRange( index * kItemsPerView, tempArray.count-index*kItemsPerView );
Alternate approach, just use MIN()
function for determining the end of the range.
Example:
NSRange range;
range.location = index * kItemsPerView;
range.length = MIN(kItemsPerView, tempArray.count - range.location);
NSArray *imagesForView = [tempArray subarrayWithRange:range];
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