ios - UICollectionView embed in a UINavigationController,but the UICollectionViewCell frame is wrong -

i have uinavigationcontroller control 2 viewcontrollers,vc1 , vc2.

the pic shows vc2. , there has uicollectionview vc2.view's subview,also there has uicollectioncell embed in uicollectionview ,as can see below.

but when push vc1 vc2 ,the uicollectioncell's frame not correct. code write :

   //vc2.m    uicollectionviewflowlayout *l = [[uicollectionviewflowlayout alloc]init];    l.itemsize = cgsizemake(self.bounds.size.width, self.bounds.size.height);    l.minimumlinespacing = 6.0f;    l.sectioninset = uiedgeinsetsmake(0, 0, 0, 6.0);    l.scrolldirection = uicollectionviewscrolldirectionhorizontal;    uicollectionview *parallaxcollection = [[uicollectionview alloc]initwithframe:frame collectionviewlayout:l];    [parallaxcollection registerclass:[collectioncell class] forcellwithreuseidentifier:@"collectioncell"];    [self addsubview:parallaxcollection]; 

and frame of cell (0,-32,320,568) in initwithframe:(cgrect)frame:

//collectioncell.m -(id)initwithframe:(cgrect)frame{      self = [super initwithframe:frame];      }     return self; } 

what's wrong me?

try resize subviews after init it. developer library says:

layoutsubviews - implement method if need more precise control on layout of subviews either constraint or autoresizing behaviors provide.

use

-(void)layoutsubviews