Question

我要求通过单击“向右”按钮将UICollectionView单元格滚动到数组中的下5个项目，然后单击“向左”按钮显示前5次。

任何人都可以通过提出任何建议来帮助我迅速做到这一点。

下面是编写的代码，在水平滚动中显示集合视图上的列表。

override func viewDidLoad() {

        super.viewDidLoad()

        self.arrFalconList = ["ic_falcon_1","ic_falcon_2","ic_falcon_3","ic_falcon_4","ic_falcon_5","ic_falcon_6","ic_falcon_7"]
    }



func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return self.arrFalconList.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let aFalconCell = collectionView.dequeueReusableCell(withReuseIdentifier: "FalconCollectionViewCell", for: indexPath) as! FalconCollectionViewCell

        aFalconCell.imgFalcon.image = UIImage(named: self.arrFalconList[indexPath.row])
        aFalconCell.lblFalcon.text = self.arrFalconList[indexPath.row]
        aFalconCell.imgFalcon.layer.cornerRadius = ((aFalconCell.imgFalcon.frame.width) / 2)
        aFalconCell.imgFalcon.clipsToBounds = true

        if aFalconCell.isSelected {
            aFalconCell.imgFalcon.layer.borderColor = UIColor.init(red: 241.0/255.0, green: 55.0/255.0, blue: 61.0/255.0, alpha: 1.0).cgColor
            aFalconCell.imgFalcon.layer.borderWidth = 2
        }else{
            aFalconCell.imgFalcon.layer.borderColor = UIColor.clear.cgColor
            aFalconCell.imgFalcon.layer.borderWidth = 0
        }


        return aFalconCell

    }

请分享您的答案以处理“左”和“左” “右”按钮点击事件。

Answer 1

我找到了查询的解决方案。

下面的代码有助于满足要求。

@IBAction func btnLeftArrowAction(_ sender: Any) {
        let collectionBounds = self.collectionView.bounds
        let contentOffset = CGFloat(floor(self.collectionView.contentOffset.x - collectionBounds.size.width))
        self.moveCollectionToFrame(contentOffset: contentOffset)

    }

    @IBAction func btnRightArrowAction(_ sender: Any) {

        let collectionBounds = self.collectionView.bounds
        let contentOffset = CGFloat(floor(self.collectionView.contentOffset.x + collectionBounds.size.width))
        self.moveCollectionToFrame(contentOffset: contentOffset)

    }

    func moveCollectionToFrame(contentOffset : CGFloat) {

        let frame: CGRect = CGRect(x : contentOffset ,y : self.collectionView.contentOffset.y ,width : self.collectionView.frame.width,height : self.collectionView.frame.height)
        self.collectionView.scrollRectToVisible(frame, animated: true)
    }

Answer 2

akash在Objective-C中的答案，除了我做了一点微小的改变：我需要一次滚动一个单元格，而不是一直向左或向右滚动。如果您需要该功能，请更改

float cellWidth = self.collectionView.visibleCells[0].bounds.size.width;

与

float collectionViewWidth = self.collectionView.bounds;

- (IBAction)scrollLeftAction:(id)sender
{
    float cellWidth = self.collectionView.visibleCells[0].bounds.size.width;
    float contentOffset = (float)(floor(self.collectionView.contentOffset.x - cellWidth));
    [self moveCollectionViewToFrame:contentOffset];
}

- (IBAction)scrollRightAction:(id)sender
{
    float cellWidth = self.collectionView.visibleCells[0].bounds.size.width;
    float contentOffset = (float)(floor(self.collectionView.contentOffset.x + cellWidth));
    [self moveCollectionViewToFrame:contentOffset];
}

- (void)moveCollectionViewToFrame:(CGFloat)contentOffset
{
    CGRect frame = CGRectMake(contentOffset, self.collectionView.contentOffset.y, self.collectionView.frame.size.width, self.collectionView.frame.size.height);
    [self.collectionView scrollRectToVisible:frame
                                    animated:YES];
}

Answer 3

你可以试试这段代码

let I = 1
   func next_btn_clicked()
{
 clooectionview.setContentOffset(CGPoint(x: (i) * clooectionview.frame.size.width, y: 0), animated: true)
I = I + 1
 }

将UICollectionView的滚动单元格滚动到左侧和右侧。点击左侧和右侧的正确方向右键动作

3 个答案: