超简单的UITableView下拉放大的动画

来源：互联网发布：软件项目质量控制编辑：程序博客网时间：2024/06/05 02:07
很多主流的app都会有这个动画,然后用最简单的思想实现了一下,就是按照tableView的contentOffset,直接进行缩放,效果还不错.
这里写图片描述
#import "ViewController.h"#import <Masonry/Masonry.h>@interface ViewController ()<UITableViewDataSource, UITableViewDelegate>@property (nonatomic, strong) UITableView *tableView;@property (nonatomic, strong) UIImageView *imageView;@property (nonatomic, strong) UITableViewCell *headerCell;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    //让automaticallyAdjustsScrollViewInsets为NO,是为了当有导航栏的时候,防止系统自动设置tableView的contentInset,这里并没有加navigationController    //self.automaticallyAdjustsScrollViewInsets = NO;    [self.view addSubview:self.tableView];    // Do any additional setup after loading the view, typically from a nib.}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}- (UITableView *)tableView{    if (!_tableView) {        _tableView = [[UITableView alloc] initWithFrame:self.view.frame];        _tableView.delegate = self;        _tableView.dataSource = self;        [_tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:@"cell"];    }    return _tableView;}- (UIImageView *)imageView{    if (!_imageView) {        _imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"user_bg"]];        _imageView.clipsToBounds = YES;    }    return _imageView;}- (UITableViewCell *)headerCell{    if (!_headerCell) {        _headerCell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"headerCell"];        //创建第一个view当做背景,令其clipsToBounds属性为yes,让imageView超出view的部分切掉        UIView *view = [[UIView alloc] init];        view.backgroundColor = [UIColor whiteColor];        view.clipsToBounds = YES;        //给view加上左,右,下三个方向上的约束        [_headerCell.contentView addSubview:view];        [view mas_makeConstraints:^(MASConstraintMaker *make) {            make.left.equalTo(_headerCell.contentView);            make.right.equalTo(_headerCell.contentView);            make.bottom.equalTo(_headerCell.contentView);        }];        [view addSubview:self.imageView];        [self.imageView mas_makeConstraints:^(MASConstraintMaker *make) {            make.edges.equalTo(view);        }];    }    return _headerCell;}#pragma mark - UITableViewDataSource- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{    return 20;}- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{    if (indexPath.row == 0) {        return self.headerCell;    }    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cell"];    cell.textLabel.text = [NSString stringWithFormat:@"zhhh%ld",indexPath.row];    return cell;}- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{    if (indexPath.row == 0) {        return 200;    }    return 44;}#pragma mark - UIScrollViewDelegate- (void)scrollViewDidScroll:(UIScrollView *)scrollView{    //利用contentOffset.y进行动画    if (scrollView.contentOffset.y < 0) {        self.imageView.transform = CGAffineTransformMakeScale(1 - (scrollView.contentOffset.y / self.view.frame.size.width), 1 - (scrollView.contentOffset.y / self.view.frame.size.width));    }}@end
0 0