ParallaxHeaderView效果

#import "ViewController.h"
#import <Masonry/Masonry.h>

static CGFloat ParallaxHeaderHeight = 235;

@interface ViewController ()<UITableViewDataSource, UITableViewDelegate, UIScrollViewDelegate>

@property (nonatomic,strong) UITableView *tableView;
@property (strong, nonatomic) UIImageView *parallaxHeaderView;
@property (strong, nonatomic) MASConstraint *parallaxHeaderHeightConstraint;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    [self.navigationController setNavigationBarHidden:YES animated:NO];
    [self.view addSubview:self.tableView];
    [self initParallaxHeaderView];
}

- (UITableView *)tableView {
    if (!_tableView) {
        _tableView = [[UITableView alloc] initWithFrame:self.view.bounds style:UITableViewStylePlain];
        _tableView.backgroundColor = [UIColor clearColor];
        _tableView.delegate = self;
        _tableView.dataSource = self;
        _tableView.estimatedRowHeight = 0;
        _tableView.sectionHeaderHeight = 0.0;
        _tableView.sectionFooterHeight = 0.0;
        _tableView.estimatedSectionHeaderHeight = 0.0;
        _tableView.estimatedSectionFooterHeight = 0.0;
        _tableView.contentInset = UIEdgeInsetsMake(ParallaxHeaderHeight, 0, 0, 0);
        [_tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:NSStringFromClass([UITableViewCell class])];
    }
    return _tableView;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return 20;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:NSStringFromClass([UITableViewCell class]) forIndexPath:indexPath];
    cell.textLabel.text = [NSString stringWithFormat:@"第%ld条测试数据",indexPath.row];
    return cell;
}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
    if (scrollView.contentOffset.y < -ParallaxHeaderHeight) {
        _parallaxHeaderHeightConstraint.mas_equalTo(-scrollView.contentOffset.y);
    }
}

- (void)initParallaxHeaderView {
    _parallaxHeaderView = [[UIImageView alloc] init];
    [self.view insertSubview:self.parallaxHeaderView belowSubview:self.tableView];
    _parallaxHeaderView.contentMode = UIViewContentModeScaleAspectFill;
    _parallaxHeaderView.image = [UIImage imageNamed:@"zrx4.jpg"];
    
    [_parallaxHeaderView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.right.mas_equalTo(self.view);
        make.top.mas_equalTo(self.mas_topLayoutGuideBottom);
        _parallaxHeaderHeightConstraint = make.height.mas_equalTo(ParallaxHeaderHeight);
    }];
}

@end