ios - Uicollectionview weird gap -

i have collection view custom flow layout , wonder why have space (right side):

it may hard notice here, though, may see gray gap between right side , cell.

here how override standard collection view flow layout remove horizontals gaps:

@implementation calendarflowlayout  - (nsarray *) layoutattributesforelementsinrect:(cgrect)rect {     nsarray *answer = [super layoutattributesforelementsinrect:rect];     nslog(@"layout blck passed");     for(int = 1; < [answer count]; ++i) {         uicollectionviewlayoutattributes *currentlayoutattributes = answer[i];         uicollectionviewlayoutattributes *prevlayoutattributes = answer[i - 1];         nsinteger maximumspacing = 0;         nsinteger origin = cgrectgetmaxx(prevlayoutattributes.frame);          if(origin + maximumspacing + currentlayoutattributes.frame.size.width < self.collectionviewcontentsize.width) {             cgrect frame = currentlayoutattributes.frame;             frame.origin.x = origin + maximumspacing;             currentlayoutattributes.frame = frame;         }     }     return answer; }  @end 

cell size calculated follow:

- (cgsize)collectionview:(uicollectionview *)collectionview                   layout:(uicollectionviewlayout *)collectionviewlayout   sizeforitematindexpath:(nsindexpath *)indexpath{       return cgsizemake(screen_width/7, (screen_height-navbar_height-status_bar_height)/6); } 

those macros above that:

#define screen_width  [[uiscreen mainscreen] bounds].size.width 

it has been tested , return correct output.

also, if set width screen_width/3, there no gap.

how remove it? why happen?

375 / 3 = 125

375 / 7 = 53.57142857142857

you can't light half pixel, rounding down, leaving gap. make sure size multiple of subview size (or add pixel rightmost object if it's not).