UICollectionView自定义单元格以填充宽度在Swift中

Question

我一直试图弄清楚如何让细胞填充宽度,正如你在图片中看到的那样,细胞之间的宽度太大了.我使用只有一个imageView的自定义单元格.

我试图从故事板中自定义它,但我想没有选择,或者它应该以编程方式完成.

我的UICollectionViewController:

 @IBOutlet var collectionView2: UICollectionView!

    let recipeImages = ["angry_birds_cake", "creme_brelee", "egg_benedict", "full_breakfast", "green_tea", "ham_and_cheese_panini", "ham_and_egg_sandwich", "hamburger", "instant_noodle_with_egg.jpg", "japanese_noodle_with_pork", "mushroom_risotto", "noodle_with_bbq_pork", "starbucks_coffee", "thai_shrimp_cake", "vegetable_curry", "white_chocolate_donut"]

    override func viewDidLoad() {
        super.viewDidLoad()

        // Uncomment the following line to preserve selection between presentations
        // self.clearsSelectionOnViewWillAppear = false

        // Do any additional setup after loading the view.

    }


    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

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 recipeImages.count
    }

    override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! RecipeCollectionViewCell

        // Configure the cell
        cell.recipeImageView.image = UIImage(named: recipeImages[indexPath.row])

        return cell
    }

Answer 1

你需要以编程方式执行此操作.

UICollectionViewDelegateFlowLayout在视图控制器中实现并提供大小collectionView:layout:sizeForItemAtIndexPath:

func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        sizeForItemAt indexPath: IndexPath) -> CGSize {
        let kWhateverHeightYouWant = 100
        return CGSizeMake(collectionView.bounds.size.width, CGFloat(kWhateverHeightYouWant))
}

您还需要collectionView.collectionViewLayout.invalidateLayout()在视图控制器内部调用,viewWillLayoutSubviews()以便在主视图的尺寸发生变化时(例如,在旋转时),重新布置集合视图.

Swift 4更新

func collectionView(_ collectionView: UICollectionView,
                            layout collectionViewLayout: UICollectionViewLayout,
                            sizeForItemAt indexPath: IndexPath) -> CGSize {
            let kWhateverHeightYouWant = 100
            return CGSize(width: collectionView.bounds.size.width, height: CGFloat(kWhateverHeightYouWant))
}

Answer 2

在视图控制器覆盖viewDidLayoutSubviews方法内

@IBOutlet weak var collectionView: UICollectionView!

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()

    if let layout = collectionView.collectionViewLayout as? UICollectionViewFlowLayout {
        let itemWidth = view.bounds.width / 3.0
        let itemHeight = layout.itemSize.height
        layout.itemSize = CGSize(width: itemWidth, height: itemHeight)
        layout.invalidateLayout()
    }
}

(collectionView属性是你的collectionView)

Answer 3

使用以下代码设置宽度UICollectionViewCell.

func collectionView(_ collectionView: UICollectionView,
                    layout collectionViewLayout: UICollectionViewLayout,
                    sizeForItemAt indexPath: IndexPath) -> CGSize {        
    return CGSize(width: screenWidth/3, height: screenWidth/3);
}

Answer 4

同样在Swift 3中,

确保您的视图控制器符合以下条件:

UICollectionViewDelegate,
UICollectionViewDataSource,
UICollectionViewDelegateFlowLayout