下拉刷新和上拉加载更多（第三方框架MJRefresh）

 #import "RootViewController.h"
 #import "MJRefresh.h"
 @interface RootViewController ()<UITableViewDataSource,UITableViewDelegate,MJRefreshBaseViewDelegate>
 {
     UITableView *_tableView ;
     NSMutableArray *datas;
     MJRefreshHeaderView *headerView;
     MJRefreshFooterView *footerView;
 }
 @end

 @implementation RootViewController

 - (void)dealloc
 {
     [headerView free];
     [footerView free];
 }

 - (void)viewDidLoad {
     [super viewDidLoad];
     //初始化tableView
     [self initializeTableView];
     // 初始化数据
     [self initializeData];
 }

 - (void)initializeTableView
 {
     _tableView = [[UITableView alloc] initWithFrame:[[UIScreen mainScreen] bounds] style:UITableViewStylePlain];
     _tableView.dataSource = self;
     [self.view addSubview:_tableView];
     // 初始化刷新控件
     [self initializeRefreshView];
 }

 - (void)initializeRefreshView
 {
     // 下拉刷新
     headerView = [MJRefreshHeaderView header];
     headerView.scrollView = _tableView;
     headerView.delegate = self;

     // 上拉加载更多
     footerView = [MJRefreshFooterView footer];
     footerView.delegate = self;
     footerView.scrollView = _tableView;
 }

 /**
  *  刷新控件进入开始刷新状态的时候调用
  */
 - (void)refreshViewBeginRefreshing:(MJRefreshBaseView *)refreshView
 {
     if ([refreshView isKindOfClass:[MJRefreshHeaderView class]]) {
         //下拉刷新
         [self loadNewData];
     }else{
         [self loadMoreData];
     }
 }
 /*
  * 刷新数据
  */
 - (void)loadNewData
 {
     static int count = ;
     NSMutableArray *array = [NSMutableArray array];
     //每次刷新五条数据
     for (int i = ; i < ; i++) {
         NSString *str = [NSString stringWithFormat:@"第%d次刷新",count];
         [array addObject:str];
     }
     // 把新数据加到datas前面
     NSMutableArray *newArray = [[NSMutableArray alloc] initWithArray:array];
     [newArray addObjectsFromArray:datas];
     datas = newArray;
     [_tableView reloadData];
     [headerView endRefreshing];
     count++;
 }

 /*
  * 加载更多数据
  */
 - (void)loadMoreData
 {
     static int count = ;
     NSMutableArray *array = [NSMutableArray array];
     for (int j = ; j < ; j++) {
         NSString *str = [NSString stringWithFormat:@"第%d次加载更多",count];
         [array addObject:str];
     }
     [datas addObjectsFromArray:array];
     [_tableView reloadData];
     [footerView endRefreshing];
     count++;
 }

 - (void)initializeData
 {
     datas = [NSMutableArray arrayWithObjects:@"A",@"B", @"C", @"D", @"E", @"F", @"G", @"H", @"I", @"J", @"K", @"L", @"M", @"N", @"O", @"P", @"Q", @"R", @"S", @"T", @"U", @"V", @"W", @"X", @"Y", @"Z",  nil];
 }

 #pragma mark -配置UITableViewDataSource数据
 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
 {
     return [datas count];
 }

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
 {
     static NSString *identify = @"cell";
     UITableViewCell *cell = [_tableView dequeueReusableCellWithIdentifier:identify];
     if (!cell) {
         cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identify];

     }
     cell.textLabel.text = datas[indexPath.row];
     return cell;
 }

 @end