在尝试了几个(而且很冒险的)解决方案后,我通过编写我自己的UICollectionView
布局来解决这个问题。以前的解决方案我尝试:
- 添加自定义的UIView上层建筑的
UICollectionView
并试图伪造原始细胞通过覆盖它,调光背景,动画,新的UIView
- 移动动画细胞,而无需创建一个全新的布局
我试图避免它,但是在编码之后,它比我原先想象的要少得多。
这里是我的代码,有兴趣的人:
.H:
@interface FMStackedLayout : UICollectionViewLayout
@property(nonatomic,assign) CGPoint center;
@property(nonatomic,assign) NSInteger cellCount;
-(id)initWithSelectedCellIndexPath:(NSIndexPath *)indexPath;
@end
.M:
#define ITEM_WIDTH 128.0f
#define ITEM_HEIGHT 180.0f
static NSUInteger const RotationCount = 32;
static NSUInteger const RotationStride = 3;
static NSUInteger const PhotoCellBaseZIndex = 100;
@interface FMStackedLayout()
@property(strong,nonatomic) NSArray *rotations;
@property(strong,nonatomic) NSIndexPath *selectedIndexPath;
@end
@implementation FMStackedLayout
#pragma mark - Lifecycle
-(id)initWithSelectedCellIndexPath:(NSIndexPath *)indexPath{
self = [super init];
if (self) {
self.selectedIndexPath = indexPath;
[self setup];
}
return self;
}
-(id)initWithCoder:(NSCoder *)aDecoder{
self = [super init];
if (self){
[self setup];
}
return self;
}
-(void)setup{
NSMutableArray *rotations = [NSMutableArray arrayWithCapacity:RotationCount];
CGFloat percentage = 0.0f;
for (NSUInteger i = 0; i < RotationCount; i++) {
// Ensure that each angle is different enough to be seen
CGFloat newPercentage = 0.0f;
do {
newPercentage = ((CGFloat)(arc4random() % 220) - 110) * 0.0001f;
} while (fabsf(percentage - newPercentage) < 0.006);
percentage = newPercentage;
CGFloat angle = 2 * M_PI * (1.0f + percentage);
CATransform3D transform = CATransform3DMakeRotation(angle, 0.0f, 0.0f, 1.0f);
[rotations addObject:[NSValue valueWithCATransform3D:transform]];
}
self.rotations = rotations;
}
#pragma mark - Layout
-(void)prepareLayout{
[super prepareLayout];
CGSize size = self.collectionView.frame.size;
self.cellCount = [self.collectionView numberOfItemsInSection:0];
self.center = CGPointMake(size.width/2.0, size.height/2.0);
}
-(CGSize)collectionViewContentSize{
return self.collectionView.frame.size;
}
-(UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath{
UICollectionViewLayoutAttributes *attributes = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
attributes.size = CGSizeMake(ITEM_WIDTH, ITEM_HEIGHT);
attributes.center = self.center;
if (indexPath.item == self.selectedIndexPath.item) {
attributes.zIndex = 100;
}else{
attributes.transform3D = [self transformForPersonViewAtIndex:indexPath];
}
return attributes;
}
-(NSArray *)layoutAttributesForElementsInRect:(CGRect)rect{
NSMutableArray *attributes = [NSMutableArray array];
for (NSInteger i = 0; i < self.cellCount; i++) {
NSIndexPath *indexPath = [NSIndexPath indexPathForItem:i
inSection:0];
[attributes addObject:[self layoutAttributesForItemAtIndexPath:indexPath]];
}
return attributes;
}
#pragma mark - Private
-(CATransform3D)transformForPersonViewAtIndex:(NSIndexPath *)indexPath{
NSInteger offset = (indexPath.section * RotationStride + indexPath.item);
return [self.rotations[offset % RotationCount] CATransform3DValue];
}
@end
然后,在你的UICollectionView,你叫
MyLayout *stackedLayout = [[MyLayout alloc] initWithSelectedCellIndexPath:indexPath];
[stackedLayout invalidateLayout];
[self.collectionView setCollectionViewLayout:stackedLayout
animated:YES];
单元格之间的动画将由自定义布局处理。
这不是一个答案。看起来你有答案,但不想分享。 – Fiveagle
@Mark Struzinski你能分享一下你的解决方案吗? –
这是一段相当长的代码,但我并没有因为任何特殊原因而退缩。我已经将其发布给任何感兴趣的人。不知道为什么在这里有downvotes。最终解决方案使用了Apple文档中详细记录的方法:http://developer.apple.com/library/ios/#documentation/uikit/reference/UICollectionViewLayout_class/Reference/Reference.html。我一直在试图避免它,因为它的工作量很大。 –