uicollectionView

http://zyc-to.blog.163.com/blog/static/1715240020140131946702/

http://blog.csdn.net/ljh910329/article/details/42421923

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.


    self.view.backgroundColor = UIColor.greenColor;

    static NSString * CellIdentifier = @"GradientCell";


    UICollectionViewFlowLayout *flowLayout=[[UICollectionViewFlowLayout alloc] init];
    [flowLayout setScrollDirection:UICollectionViewScrollDirectionVertical];

    _collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(10, 30, 300, 300) collectionViewLayout:flowLayout];

    _collectionView.backgroundColor = [UIColor whiteColor];
    [_collectionView registerClass:[JZLImageLabelCollectionViewCell class] forCellWithReuseIdentifier:CellIdentifier];

    [_collectionView registerClass:[JZLCollectionHeaderView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"header"];

    _collectionView.delegate = self;
    _collectionView.dataSource = self;

    [self.view addSubview:_collectionView];

}

#pragma mark - UICollectionViewDataSource Methods

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 3;
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return 16;
}

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
    UICollectionReusableView *reusableView = nil;

    if (kind == UICollectionElementKindSectionHeader) {
        // 定制头部视图的内容

        JZLCollectionHeaderView *headerV = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"header" forIndexPath:indexPath];

        headerV.titleLable.text = @"-----头-----";
        reusableView = headerV;
    }

    return reusableView;
}

// The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString * CellIdentifier = @"GradientCell";

    JZLImageLabelCollectionViewCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];

//    cell.backgroundColor = [UIColor colorWithRed:((10 * indexPath.row) / 255.0) green:((20 * indexPath.row)/255.0) blue:((30 * indexPath.row)/255.0) alpha:1.0f];


    [cell.imageView setImage:[UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"%ld", (long)indexPath.row] ofType:@"png"]]];

    cell.label.text = [NSString stringWithFormat:@"{%ld,%ld}",(long)indexPath.section, (long)indexPath.row];


    return cell;
}

#pragma mark --UICollectionViewDelegateFlowLayout Methods

//设置顶部的大小
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section{

    CGSize size={collectionView.frame.size.width,50};

    return size;

}

// 定义每个UICollectionView 的 margin
-(UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
    CGFloat edgeFloat = 10;
    return UIEdgeInsetsMake(edgeFloat, edgeFloat, edgeFloat, edgeFloat);
}

// 定义每个UICollectionView 的大小
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return CGSizeMake((collectionView.frame.size.width - 80) / 4.0, (collectionView.frame.size.width - 80) / 4.0);
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section
{

    return 10.0;
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section
{
    return 10;
}

#pragma mark - UICollectionViewDelegate Methods

- (BOOL)collectionView:(UICollectionView *)collectionView shouldHighlightItemAtIndexPath:(NSIndexPath *)indexPath
{
    return YES;
}

// UICollectionView被选中时调用的方法
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell * cell = (UICollectionViewCell *)[collectionView cellForItemAtIndexPath:indexPath];
//    cell.backgroundColor = [UIColor whiteColor];

    [collectionView deselectItemAtIndexPath:indexPath animated:YES];

    NSLog(@"%@", indexPath);
}

// 返回这个UICollectionView是否可以被选择
-(BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    return YES;
}

// 头视图

#import <UIKit/UIKit.h>

@interface JZLCollectionHeaderView : UICollectionReusableView

@property (nonatomic, strong) UILabel *titleLable;

@end

// cell样式

#import <UIKit/UIKit.h>

@interface JZLImageLabelCollectionViewCell : UICollectionViewCell

@property (nonatomic, strong) UIImageView *imageView;

@property (nonatomic, strong) UILabel *label;

@end