CODEWITHSUNDEEP
iosobjective-cuicollectionview
Payal Maniyar
Payal Maniyar

Reputation: 4402

cellForItemAtIndexPath is not called for collectionView

I have taken UICollectionView in storyboard. I have set datasource and delegate also. below method is called

 - (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
 return 4;
}

But - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath is not called.

Attaching screenshot of properties of UICollectionView. Any idea about this problem?image 1

enter image description here

Now collectionView is visible if I hide the navigationBar. In have set top constraint Myheader Collection View.top = Top Layout Guide.bottom + 64 thought it is at top of controller. and I am receiving follwing warning after completion of method -- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath.

Warning: nable to simultaneously satisfy constraints. Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. ( "<_UILayoutSupportConstraint:0x7fda80dcff20 V:[_UILayoutGuide:0x7fda830006f0(0)]>", "<_UILayoutSupportConstraint:0x7fda80daca10 V:|-(0)-[_UILayoutGuide:0x7fda830006f0] (Names: '|':UIView:0x7fda80efb580 )>", "", "" )

Will attempt to recover by breaking constraint

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger. The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in may also be helpful.

Upvotes: 3

Views: 5520

Answers (3)

Payal Maniyar
Payal Maniyar

Reputation: 4402

[myCollectionView setContentInset:UIEdgeInsetsMake(100, 0, 0, 0)];

Above line solves my problem.

Upvotes: 0

Badal Shah
Badal Shah

Reputation: 7612

I think you didn't set flow out correctly.

So, it will not go to - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath method . so, set break point and check each and every flow layout method.

Sequence call of flow layout method ,

1 st in viewdidload customflowlayout will be called like , //if you have set

 UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
    [flowLayout setScrollDirection:UICollectionViewScrollDirectionVertical];
    float ratio = self.aCollectionView.frame.size.width/3;
    [flowLayout setItemSize:CGSizeMake(ratio, ratio)];
    [flowLayout setMinimumInteritemSpacing:0];
    [flowLayout setMinimumLineSpacing:0];

2nd , in your case this method also called

- (NSInteger)collectionView:(UICollectionView *)view numberOfItemsInSection:(NSInteger)section

3rd - you need to check from this line , // you have set it correctly or not

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    float width = collectionView.frame.size.width/3;//120
    float height = collectionView.frame.size.height/4;//120
    return CGSizeMake(width-17,height-14);
}

4th , this method called

- (UIEdgeInsets)collectionView:
(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
    return UIEdgeInsetsMake(14.0, 14.0, 0.0, 14.0);
}

and last here cellforitem method is called . so, your this method not called so, problem is in above method try to set break point and change cell size and edge insect and etc and then try,

5th , if all above set correct then , below method called.

- (UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:(NSIndexPath *)indexPath

Upvotes: 4

Mike Gledhill
Mike Gledhill

Reputation: 29213

I had a similar issue a few years ago with my UITableView, and the solution was to drag'n'drop from my control to the parent view, in the Storyboard.

Just setting the values in my Objective-C code didn't seem to be enough...

enter image description here

Full details here:

Setting DataSource and delegate

Upvotes: 0

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