UICollectionView - Not displaying cells

Question

What I'm trying to achieve is a 3x3 table with UICollectionView. But it just doesn't display any cells when running the application. It does display the background color of the CollectionView though (which I set to blue) Can someone help me here?

What I have done is create a storyboard and simply dragged a CollectionViewController onto it. This controller also brought a nested CollectionView with it. Then I simply used the settings to make its background blue and to add a cell to it of which I made the background purple (both only for testing). Finally dragged a UILabel onto it. Now when run it just displays the blue background but no cells even though they are clearly visible in the editor. I've then tried to create a custom UICollectionViewController, assign the class to the CollectionViewController instead of the standard class and did the same to the cell (assign a custom UICollectionViewCell). In the custom UICollectionViewController I implemented the following methods:

-(NSIntegear)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 1;
}

-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return 9;
}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellIdentifier = @"Cell";
    AboutYourGoalsMultiSelectionCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
    [[cell goal]setText:@"T"];

    return cell;
}

I set the identifier of the cell to "Cell" and made an outlet connection of dataSource and delegate between the CollectionView and the custom UICollectionViewController. Everything compiles fine. So what am I missing? Shouldn't it have displayed something way before doing all these tweaks by simply using the editor?

Answer 1

See my answer here, in short, you need to delete this line if you are working with a storyboard:

 // Register cell classes
    [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:reuseIdentifier];

Answer 2

A common source of error is that dataSource and delegate are not set in the Outlets

Answer 3

You have an error in the first line of your code.

-(NSIntegear)numberOfSectionsInCollectionView:(UICollectionView *)collectionView

NSIntegear should be NSInteger.

Not sure if that's the problem though because xcode shouldn't allow you to run your project with this error. I just tried following the exact same steps you mentioned (without the label) but with the above correction and it worked fine for me. Here is a screenshot:

Answer 4

Since I didn't find a direct solution to it I've tried to set up a new project and did the same changes and tweaks and surprisingly, this time, everything worked from the beginning. I then copied the storyboard to my old project, deleted all the old files and replaced it with the files from the new project. Everything is working good so far. I have no idea what the actual error was but I'm happy it's working now. Thanks to everyone who had a look at my question!

Answer 5

If you are trying to create just a simple CollectionViewController (not custom i.e. by implementation) and your cells are not displaying when application runs just follow the following steps:-

• First of all you have to create the cocoa touch class (if not created) for your UICollectionViewController. FILE -> NEW -> COCOA TOUCH CLASS then choose UICollectionViewController from drop down list of subclass.
• Now under your identity inspector section of your CollectionViewController add your class by choosing from the drop down list of Custom Class.

• Now open your created class and edit your methods like this:

  override func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
  //#warning Incomplete method implementation -- Return the number of sections
  return 1
   }
   override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
  //#warning Incomplete method implementation -- Return the number of items in the section
  return 1
  }
  

• Only edit "return" value (which is 0 by default) just simply write the number of cells/items you want to display or you have created (in this case here i only had created one Cell).

[ios] [swift3] [xcode]