ios - UICollectionViewCell and UIScrollView -

i encountered weird behavior of uiscrollview when inside uicollectionviewcell. in project have collectionview , each cell has uiscrollview contains 1 or more images. here's sample code purpose of question:

- (uicollectionviewcell *)collectionview:(uicollectionview *)cv cellforitematindexpath:(nsindexpath *)indexpath {        customcollectioncell * cell = [cv dequeuereusablecellwithreuseidentifier:@"customcell" forindexpath:indexpath];      uiimageview * imageview = [[uiimageview alloc] initwithframe:cgrectmake(20, 20, 150, 150)];      imageview.image = [uiimage imagenamed:@"someimage.png"];              [cell.scrollview addsubview:imageview];       return cell; } 

of course in project it's not same image different ones fed database.

the first collection cell added no problem. when add second cell, scrollview seems duplicate , place instance of on top. know sounds weird, can see how looks in image below:

notice how image in scrollview on left has darkened, assume it's because scrollview duplicated.

so, i'm guessing cell reused in wrong way or something.

thanks help!

a new uiimageview being added reused cell each time collectionview: cellforitematindexpath: invoked. solve this, in custom uicollectionviewcell, implement prepareforreuse method. in method, remove image view.

to accomplish this, set tag on image view. e.g.,:

 (uicollectionviewcell *)collectionview:(uicollectionview *)cv cellforitematindexpath:(nsindexpath *)indexpath {        customcollectioncell * cell = [cv dequeuereusablecellwithreuseidentifier:@"customcell" forindexpath:indexpath];      uiimageview * imageview = [[uiimageview alloc] initwithframe:cgrectmake(20, 20, 150, 150)];      imageview.image = [uiimage imagenamed:@"someimage.png"];              [cell.scrollview addsubview:imageview];       // following line of code new      cell.contentview.tag = 100;       return cell; } 

and remove image view cell, add/update prepareforreuse method in custom cell:

-(void)prepareforreuse{     uiview *myimageview = [self.contentview viewwithtag:100];     [myimageview removefromsuperview]; }