iOS开发笔记之UICollectionView的简单使用

        UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
        layout.itemSize = CGSizeMake(500 * Width_Ratio, 590 * Width_Ratio);  // item尺寸
        layout.minimumLineSpacing = 24 * Width_Ratio;  // 行最小间距
        layout.minimumInteritemSpacing = 20 * Width_Ratio;  // 列最小间距
        layout.sectionInset = UIEdgeInsetsMake(31 * Width_Ratio, (Screen_Width - 1024 * Width_Ratio)/2, 31 * Width_Ratio, (Screen_Width - 1024 * Width_Ratio)/2);  // section四边缩进
        layout.headerReferenceSize = CGSizeMake(Screen_Width, 535 * Width_Ratio);  // headerView的尺寸
        
        UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, Screen_Width, Screen_Height) collectionViewLayout:layout];
        collectionView.backgroundColor = UIColorFromHex(0xf4f4f4);
        collectionView.showsVerticalScrollIndicator = NO;
        collectionView.dataSource = self;
        collectionView.delegate = self;
        collectionView.alwaysBounceVertical = YES;
        [collectionView registerClass:[ClawCollectionViewCell class] forCellWithReuseIdentifier:kHomeViewControllerCellIdenfider];
        [collectionView registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"collectionHeaderView"];
        [self.view addSubview:collectionView];
        

#pragma mark - UICollectionViewDataSource

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    return self.list.count;  // item数量
}

- (__kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
    ClawCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:kHomeViewControllerCellIdenfider forIndexPath:indexPath];
    
    return cell;
}
// header/footer View
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath {
    UICollectionReusableView *reusableview = nil;
    reusableview = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"collectionHeaderView" forIndexPath:indexPath];
        
    return reusableview;
}

#pragma mark - UICollectionViewDelegate
// 点击item
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
   
}