效果圖.gif
#import "ViewController.h"
@interface ViewController ()<UITableViewDelegate>
{
}
@property (nonatomic , strong) UIImageView *headerImageView; /**< <#description#> */
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
UIView *titleView = [[UIView alloc] init];
self.navigationItem.titleView = titleView;
NSLog(@"%@",NSStringFromCGRect(self.navigationItem.titleView.frame));
self.headerImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 40, 40)];
self.headerImageView.layer.cornerRadius = 20.f;
self.headerImageView.layer.masksToBounds = YES;
self.headerImageView.image = [UIImage imageNamed:@"head"];
// 保證用戶(hù)頭像水平居中
self.headerImageView.center = CGPointMake(titleView.center.x, 0);
[titleView addSubview:self.headerImageView];
UITableView *tableView = [[UITableView alloc] initWithFrame:CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height)];
tableView.backgroundColor = [UIColor whiteColor];
[self.view addSubview:tableView];
tableView.delegate = self;
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat offsetY = scrollView.contentOffset.y + scrollView.contentInset.top;
CGFloat scale = 1.f;
// 放大
if (offsetY < 0) {
scale = MIN(1.5, 1 - offsetY / 300);
} else if (offsetY > 0) {
// 縮小
scale = MAX(0.45, 1 - offsetY / 300);
}
//進(jìn)行縮放
self.headerImageView.transform = CGAffineTransformMakeScale(scale, scale);
// 保證縮放后y坐標(biāo)不變
CGRect frame = self.headerImageView.frame;
frame.origin.y = -self.headerImageView.layer.cornerRadius / 2;
self.headerImageView.frame = frame;
}
@end
