//定義顯示部分的數量。
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collection view;
//每個UICollectionView顯示的內容。
-(UICollectionView cell *)collection view:(UICollectionView *)collection view cellForItemAtIndexPath:(NSIndexPath *)index path;
在UICollectionView中設置屬性。
//定義每個UICollectionView的大小(返回CGSize: width和height)。
-(CGSize)collection view:(UICollectionView *)collection view layout:(UICollectionView layout *)collection view layout sizeForItemAtIndexPath:(NSIndexPath *)index path;
//定義每個UICollectionView的間距(返回UIEdgeInsets: top、left、bottom和right)。
-(UIEdgeInsets)collection view:(UICollectionView *)collection view layout:(UICollectionView layout *)collection view layout insetForSectionAtIndex:(NSInteger)section;
//定義每個UICollectionView的垂直間距。
-(CG float)collection view:(UICollectionView *)collection view layout:(UICollectionView layout *)collection view layout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section;
//選擇//UICollectionView時調用的方法
-(void)collection view:(UICollectionView *)collection view didSelectItemAtIndexPath:(NSIndexPath *)index path;