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标题: ios - UICollectionView 中的动画自定义布局 [打印本页]

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作者: 菜鸟教程小白    时间: 2022-12-12 12:34
标题: ios - UICollectionView 中的动画自定义布局

我需要创建一个如下图所示的 UICollectionView。

我已经能够使水平滚动，但无法使 UI 像图片一样。有什么帮助吗？谢谢。

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Best Answer-推荐答案

这就是你想要的，你只需要一个自定义的 UICollectionViewFlowLayout，并重写方法 -(NSArray *)layoutAttributesForElementsInRectCGRect)rect 来改变单元格显示属性.

这是每个主要操作中带有注释的布局代码

@implementation HorizonSclaeLayout

-(instancetype)init{
     self = [super init];
     if (self) {
         self.scrollDirection = UICollectionViewScrollDirectionHorizontal;
     }
     return self;
 }

 static const CGFloat kMaxDistancePercentage = 0.3f;
 static const CGFloat kMaxRotation = 0;//(CGFloat)(70.0 * (M_PI / 180.0));
 static const CGFloat kMaxZoom = 0.6f;

 -(NSArray<UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRectCGRect)rect{
     //1 the visible rectangle of the collection view, calculated using the content offset of the view and the bounds size.
     CGRect visibleRect = (CGRect){
         .origin = self.collectionView.contentOffset,
         .size = self.collectionView.bounds.size
     };

     //2 the maximum distance away from the center, which defines the distance from the center at which each cell is fully rotated
     CGFloat maxDistance = visibleRect.size.width/2;
     NSArray *array = [super layoutAttributesForElementsInRect:rect];

     for (UICollectionViewLayoutAttributes *attributes in array) {
         //3 find the distance of the cell from the center of the current visible rectangle
         CGFloat distance = CGRectGetMidX(visibleRect) - attributes.center.x;

         //4 normalize this distance against the maximum distance to give a percentage of how far the view is along the line from the center to the maximum points in either direction
         CGFloat normalizedDistance = distance / maxDistance;
         normalizedDistance = MIN(normalizedDistance, 1.0f);
         normalizedDistance = MAX(normalizedDistance, -1.0f);

         //5 calculate the rotation and zoom
         CGFloat rotation = normalizedDistance * kMaxRotation;
         CGFloat zoom = 1.0f + ((1.0f - ABS(normalizedDistance))*kMaxZoom);

         //6 create the required transform by first setting m34 so that when the rotation is done
         // skew is applied to make it have the appearance of coming out of and going into the screen
         CATransform3D transform = CATransform3DIdentity;
         transform.m34 = - 1.0 / 550.0;
         transform = CATransform3DRotate(transform, rotation, 0.0f, 1.0f, 0.0f);
         transform = CATransform3DScale(transform, zoom, zoom, 0.0f);
         attributes.transform3D = transform;
     }
     return array;
 }

 -(CGSize)itemSize{
     return CGSizeMake(60, 60 * 1.2);
 }

 -(CGFloat)minimumLineSpacing{
     return 30;
 }

 -(BOOL)shouldInvalidateLayoutForBoundsChangeCGRect)newBounds{
     return YES;
 }
 @end

关于ios - UICollectionView 中的动画自定义布局，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41207199/

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