UICollectionView

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    // 他是苹果官方提供的一种瀑布流效果

    UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];

    // 不同于tableView,它用item进行显示,所有需要先设置每个item有大

    flowLayout.itemSize = CGSizeMake(75, 110);

    UICollectionView *collectView = [[UICollectionView alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height) collectionViewLayout:flowLayout];

    // 和tableView很像

    // 行间距

    flowLayout.minimumLineSpacing = 10;

    // 列间距

    flowLayout.minimumInteritemSpacing = 10;

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    // 通过注册的方式创建cell

    // 注册对象类型,重用标志

  

  [collectView registerClass:[MyCell class] forCellWithReuseIdentifier:@"reuse"];

    collectView.contentInset = UIEdgeInsetsMake(0, 20, 0, 20);

    [self createData];

    flowLayout.headerReferenceSize = CGSizeMake(0, 300);

//    flowLayout.footerReferenceSize = CGSizeMake(0, 300);

    [collectView registerClass:[MyCollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"headerView"];

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// 单例

#import "User.h"

@implementation User

+(User *)shareUSer{

    static User *user;

    static dispatch_once_t oneToken;

    dispatch_once(&oneToken, ^{

        user = [[User alloc] init];

    });

    return user;

}

@end

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