ios - Adding UICollectionViewLayout programmatically issue -

i'm trying implements this library without using storyboard (first step implementing library) , because i'm creating uicollectionview programmatically.

    - (void)viewdidload {     [super viewdidload];     // additional setup after loading view.     //self.view.backgroundcolor = [uicolor whitecolor];     [self.view addsubview:self.collectionview];      [_collectionview registernib:[uinib nibwithnibname:@"mycell" bundle:nil] forcellwithreuseidentifier:@"cell3"];     [_collectionview setbackgroundcolor:[uicolor colorwithred:0.945 green:0.945 blue:0.945 alpha:1] ];     [_collectionview settransform:cgaffinetransformmakescale(-1, 1)];      rfquiltlayout* layout = (id)[_collectionview collectionviewlayout];     layout.direction = uicollectionviewscrolldirectionvertical;     layout.blockpixels = cgsizemake(100, 100); }   - (uicollectionview *)collectionview {     if (!_collectionview) {         cgrect collectionviewframe = self.view.bounds;         collectionviewframe.size.height -= (self.navigationcontroller.viewcontrollers.count > 1 ? 0 : (cgrectgetheight(self.tabbarcontroller.tabbar.bounds))) + 0;         //        fmmosaiclayout *mosaiclayout = [[fmmosaiclayout alloc] init];         ////        _collectionview = [[uicollectionview alloc] initwithframe:collectionviewframe collectionviewlayout:mosaiclayout]; //                rfquiltlayout* layout = (id)[_collectionview collectionviewlayout]; //                layout.direction = uicollectionviewscrolldirectionvertical; //                layout.blockpixels = cgsizemake(100, 100);         _collectionview = [[uicollectionview alloc] initwithframe:collectionviewframe collectionviewlayout:[[rfquiltlayout alloc] init]];         _collectionview.delegate = self;         _collectionview.datasource = self;      }     return _collectionview; } 

but didn't worked , nothing shown in view (no error , empty view that's all) using debugger i've notified uicollectionview method never called

first of all, collectionview method not called because using _collectionview instead self.collectionview in viewdidload method. need write self every property call setter , getter methods.

second, if want add custom layout without storyboard of xib, need set programmatically:

rfquiltlayout* layout = [[rfquiltlayout alloc] init]; layout.direction = uicollectionviewscrolldirectionvertical; layout.blockpixels = cgsizemake(100, 100); self.collectionview.collectionviewlayout = layout;