上拉刷新下拉加载

import “ViewController.h”

@interface ViewController ()

@property (nonatomic, strong) UIScrollView * scrollView;

@end

@implementation ViewController

• (UIScrollView *)scrollView {

  if (!_scrollView) {
  _scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
  _scrollView.contentSize = CGSizeMake(0, 900);
  _scrollView.backgroundColor = [UIColor grayColor];
  _scrollView.delegate = self;

  UIView * greenView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 900)];greenView.backgroundColor = [UIColor greenColor];[_scrollView addSubview:greenView];

  }
  return _scrollView;
  }

• (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView {

  //下拉刷新

  if (scrollView.contentOffset.y < -100) {

  [UIView animateWithDuration:1.0 animations:^{    self.scrollView.contentInset = UIEdgeInsetsMake(100, 0, 0, 0);} completion:^(BOOL finished) {    NSLog(@"发起下拉刷新");    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{        [UIView animateWithDuration:1.0 animations:^{            self.scrollView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0);        }];    });}];

  }

  //上拉加载

  if (scrollView.bounds.size.height + scrollView.contentOffset.y >scrollView.contentSize.height) {

  [UIView animateWithDuration:1.0 animations:^{    self.scrollView.contentInset = UIEdgeInsetsMake(0, 0, 50, 0);} completion:^(BOOL finished) {    NSLog(@"发起上拉加载");    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{        [UIView animateWithDuration:1.0 animations:^{            self.scrollView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0);        }];    });}];

  }

}

• (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view, typically from a nib.
  [self.view addSubview:self.scrollView];

}

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }

@end