UIScrollView底层实现:修改bounds,就等于UIScrollView的contentOffset偏移量
#import "ViewController.h"
@interface ViewController ()<UIScrollViewDelegate>
@property (nonatomic, weak) UIView *scrollView;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
UIView *scorllView = [[UIView alloc] initWithFrame:self.view.bounds];
[self.view addSubview:scorllView];
_scrollView = scorllView;
// 添加pan手势
UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
[scorllView addGestureRecognizer:pan];
UISwitch *switchView = [[UISwitch alloc] init];
[scorllView addSubview:switchView];
// 1.UIView 添加一个pan手势
// 2.手指往上移动,内容往上走,想看下面的内容,bounds.y++
}
- (void)pan:(UIPanGestureRecognizer *)pan
{
// 获取手指偏移量
CGPoint transP = [pan translationInView:pan.view];
CGFloat offsetY = -transP.y;
// 修改bounds
CGRect bounds = _scrollView.bounds;
bounds.origin.y += offsetY;
_scrollView.bounds = bounds;
// 复位
[pan setTranslation:CGPointZero inView:pan.view];
// NSLog(@"%f",offsetY);
}
// 只要一滚动就会调用
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
NSLog(@"%@ %@",NSStringFromCGPoint(scrollView.contentOffset),NSStringFromCGRect(scrollView.bounds));
}
//
@end
02-UIScrollView底层实现
原文：http://www.cnblogs.com/ITBKYOfZLK/p/5132162.html
