1）頭視圖和尾部視圖的添加
UICollectionReusableView *headerView = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"headerView" forIndexPath:indexPath];
UICollectionReusableView *footerView = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@"footerView" forIndexPath:indexPath];
2）內嵌（需求就是UICollectionView沒有像Tableview一樣的TabHeaderView），想要制造一個
contentInset
3）沒有注冊
[_collectionView registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"headerView"];
[_collectionView registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionFooter withReuseIdentifier:@"footerView"];
2.使用UICollectionView遇到的復用問題
1）頭視圖的使用
for (UIView *view in headerView.subviews) {
[view removeFromSuperview];
}
for (UIView *view in footerView.subviews) {
[view removeFromSuperview];
}
2）cell的復用
KnowledgeBasePopCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"KnowledgeBasePopCell" forIndexPath:indexPath];
3.使用UICollectionView不走代理的問題
1）item尺寸計算錯誤
2）禁止使用0.01這種尺寸
//每個item之間的間距
-(CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section{
return 0.01;
}
//定義每個Section 的 margin
-(UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{
return UIEdgeInsetsMake(0.01,0.01,0.01,0.01);
}
上述兩個是不走-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
3）在window上添加view，view上添加UICollectionView，是不走-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
使用各種手勢沖突判斷解決方法，但是都沒有效果
是UICollectionViewCell視圖？
是UICollectionView類？
都不能捕捉到點擊事件
解決方法：
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{
if ([touch.view isDescendantOfView:self.collectionView]) {
return NO;
}
return YES;
}
4。使用UICollectionView組頭也可以懸停
UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
//header
flowLayout.sectionHeadersPinToVisibleBounds = YES;
//footer
flowLayout.sectionFootersPinToVisibleBounds = YES;
問題：這僅在iOS9中才支持這種設置
by:ml