ios - How to identify specific cell in UICollectionview -

i want set color black color cell1,cell4,cell7 ,...n & white color cell2,cell5,cell8 ,...n note: number of cell not fixed.

how can implement this??

i assume cellforitematindexpath knows how cell number (i.e. 1, 2, 3, 4 on picture) nsindexpath passed method. can decide on color use obtaining remainder of division 3, this:

// decode index path cell number picture int cellnumber = [self getcellnumberfromindexpath:indexpath]; // figure out color if (cellnumber % 3 == 1) {     // 1, 4, 7, etc     ... // use black color } else if (cellnumber % 3 == 2) {     // 2, 5, 8, etc     ... // use white color }