这篇文章说下：MJRefresh和  EGOTableViewPullRefresh 的使用方法最下面有原理说明，若有不对或者建议请评论指出，先谢谢了：

首先是英文原文和类库下载地址：https://github.com/emreberge/EGOTableViewPullRefresh

然后创建好自己使用的tableview控件接着：

• 添加 QuartzCore.framework 到你的工程中。
• 将 EGOTableViewPullRefresh 拖到你的工程目录下。

然后在需要使用的类里写上

下拉是一个刷新的工作，所以需要我们添加的代码无非就是数据刷新的代码。

（1）在.h文件中添加如下代码

（2）在- (void)viewDidLoad函数中添加下面的代码。

（3）在对应的.m文件中添加如下方法

4、总结

总的来说，实现这一功能并不复杂，关键在于-(void)reloadTableViewDataSource这一方法。这里我试了一下，读取数据的操作必须是异步的，要不然和tableView下拉再上弹这个动作会有很明显的延迟。再一次感受到了开源类库的强大，感谢这些大神们的无私贡献，让我们这些iOS开发初学者有机会能做出漂亮的应用。

也可以设置一个基类然后其他uitableview继承它：

.h

static NSString *CELL_ID = @"cell_id";

@class BaseTableView;

@protocol BaseTableViewDelegate <NSObject>

@optional

//下拉事件

- (void)pullDown:(BaseTableView *)tableView;

//上拉事件

- (void)pullUp:(BaseTableView *)tableView;

//选中单元格事件

- (void)didSelectRowAtIndexPath:(BaseTableView *)tabelView indexPath:(NSIndexPath *)indexPath;

@end

typedefvoid(^PullDonwFinish)(void);

typedefvoid(^PullUpFinish)(void);

@interface BaseTableView :UITableView<EGORefreshTableHeaderDelegate,UITableViewDataSource, UITableViewDelegate>

{

EGORefreshTableHeaderView *_refreshHeaderView;

BOOL _reloading;

UIButton *_moreButton;

}

@property(nonatomic,retain) NSMutableArray *data;

//是否显示下拉控件

@property(nonatomic,assign)BOOL refreshHeader;

//是否有更多(下一页)

@property(nonatomic,assign)BOOL isMore;

@property(nonatomic,copy)PullDonwFinish finishBlock;

@property(nonatomic,copy)PullUpFinish pullUpBlock;

//上拉代理对象

@property(nonatomic,assign)id<BaseTableViewDelegate> refreshDelegate;

//自动执行下拉动作

-(void)launchRefreshing;

- (void)reloadTableViewDataSource;

- (void)doneLoadingTableViewData;

@end

- (id)initWithFrame:(CGRect)frame

{

self = [superinitWithFrame:frame];

if (self) {

// Initialization code

[self_initViews];

}

return self;

}

- (void)awakeFromNib {

[superawakeFromNib];

[self_initViews];

}

- (void)_initViews {

self.backgroundColor =RGB(242, 243, 240);

self.refreshHeader =YES;

self.isMore =YES;

self.delegate =self;

self.dataSource =self;

_moreButton = [UIButtonbuttonWithType:UIButtonTypeCustom];

_moreButton.frame =CGRectMake(0,0, self.width,44);

_moreButton.backgroundColor = [UIColorclearColor];

[_moreButtonsetTitle:@""forState:UIControlStateNormal];

_moreButton.titleLabel.font = [UIFontsystemFontOfSize:12.0f];

[_moreButtonsetTitleColor:[UIColorlightGrayColor] forState:UIControlStateNormal];

[_moreButtonaddTarget:selfaction:@selector(loadMoreAction)forControlEvents:UIControlEventTouchUpInside];

UIActivityIndicatorView *activityView = [[UIActivityIndicatorViewalloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];

activityView.frame =CGRectMake(90,10, 20, 20);

[activityViewstopAnimating];

activityView.tag =2013;

[_moreButtonaddSubview:activityView];

self.tableFooterView =_moreButton;

}

-(void)launchRefreshing

{

if (_reloading) {

_reloading = NO;

[UIViewanimateWithDuration:0.4animations:^{

[selfsetContentOffset:CGPointMake(0, -80)];

}completion:^(BOOL finished) {

if (finished) {

//设置停止拖拽

[_refreshHeaderViewperformSelector:@selector(egoRefreshScrollViewDidEndDragging:)withObject:selfafterDelay:0.2];

}

}];

}else{

//下拉之前还原_refreshHeaderView的state

[_refreshHeaderViewsetState:EGOOPullRefreshNormal];

[UIViewanimateWithDuration:0.4animations:^{

[selfsetContentOffset:CGPointMake(0, -80)];

}completion:^(BOOL finished) {

if (finished) {

[_refreshHeaderViewsetState:EGOOPullRefreshPulling];

//设置停止拖拽

[_refreshHeaderViewperformSelector:@selector(egoRefreshScrollViewDidEndDragging:)withObject:selfafterDelay:0.2];

}

}];

}

}

- (void)setRefreshHeader:(BOOL)refreshHeader {

_refreshHeader = refreshHeader;

if (self.refreshHeader) {

if (_refreshHeaderView ==nil) {

//创建下拉控件

_refreshHeaderView = [[EGORefreshTableHeaderViewalloc] initWithFrame:CGRectMake(0.0f,0.0f - self.bounds.size.height,self.frame.size.width,self.bounds.size.height)];

_refreshHeaderView.delegate =self;

_refreshHeaderView.backgroundColor = [UIColorclearColor];

[_refreshHeaderViewrefreshLastUpdatedDate];

}

[selfaddSubview:_refreshHeaderView];

}else {

if (_refreshHeaderView.superview !=nil) {

[_refreshHeaderViewremoveFromSuperview];

}

}

}

//上拉按钮的点击事件

- (void)loadMoreAction {

if (self.pullUpBlock !=nil) {

self.pullUpBlock();

}

//调用代理对象的协议方法

if ([self.refreshDelegaterespondsToSelector:@selector(pullUp:)]) {

[self.refreshDelegatepullUp:self];

}

[_moreButtonsetTitle:@"正在加载..."forState:UIControlStateNormal];

UIActivityIndicatorView *activityView = (UIActivityIndicatorView *)[_moreButtonviewWithTag:2013];

[activityViewstartAnimating];

}

- (void)setIsMore:(BOOL)isMore {

_isMore = isMore;

if (self.isMore) {

[_moreButtonsetTitle:@"加载更多数据"forState:UIControlStateNormal];

_moreButton.enabled =YES;

}else {

[_moreButtonsetTitle:@"没有更多数据"forState:UIControlStateNormal];

_moreButton.enabled =NO;

}

UIActivityIndicatorView *activityView = (UIActivityIndicatorView *)[_moreButtonviewWithTag:2013];

[activityViewstopAnimating];

}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

{

[tableView deselectRowAtIndexPath:indexPathanimated:YES];

}

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

{

return self.data.count;

}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

UITableViewCell *cell = [tableViewdequeueReusableCellWithIdentifier:CELL_ID];

if (!cell) {

cell = [[UITableViewCellalloc] initWithStyle:UITableViewCellStyleDefaultreuseIdentifier:CELL_ID];

}

return cell;

}

/*________________________下拉控件相关方法________________________________*/

#pragma mark -

#pragma mark Data Source Loading / Reloading Methods

- (void)reloadTableViewDataSource{

_reloading = YES;

}

//收起下拉刷新

- (void)doneLoadingTableViewData{

_reloading = NO;

[_refreshHeaderViewegoRefreshScrollViewDataSourceDidFinishedLoading:self];

}

#pragma mark -

#pragma mark UIScrollViewDelegate Methods

- (void)scrollViewDidScroll:(UIScrollView *)scrollView{

[_refreshHeaderViewegoRefreshScrollViewDidScroll:scrollView];

}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{

[_refreshHeaderViewegoRefreshScrollViewDidEndDragging:scrollView];

//偏移量.y + tableView.height =内容的高度

//h是上拉超出来的尺寸

float h = scrollView.contentOffset.y + scrollView.height - scrollView.contentSize.height;

if (h > 30 &&self.isMore) {

[selfloadMoreAction];

}

}

#pragma mark -

#pragma mark EGORefreshTableHeaderDelegate Methods

//下拉到一定距离，手指放开时调用

- (void)egoRefreshTableHeaderDidTriggerRefresh:(EGORefreshTableHeaderView*)view{

[selfreloadTableViewDataSource];

//停止加载，弹回下拉

// [self performSelector:@selector(doneLoadingTableViewData)

//               withObject:nil afterDelay:3.0];

if (self.finishBlock !=nil) {

self.finishBlock();

}

if ([self.refreshDelegaterespondsToSelector:@selector(pullDown:)]) {

[self.refreshDelegatepullDown:self];

}

}

- (BOOL)egoRefreshTableHeaderDataSourceIsLoading:(EGORefreshTableHeaderView*)view{

return_reloading;// should return if data source model is reloading

}

//取得下拉刷新的时间

- (NSDate *)egoRefreshTableHeaderDataSourceLastUpdated:(EGORefreshTableHeaderView*)view{

return [NSDatedate]; // should return date data source was last changed

}

@end

浅谈下拉刷新和上拉加载更多原理：

下文出自：  http://blog.csdn.net/hmt20130412/article/details/32695305

很多App中,新闻或者展示类都存在下拉刷新和上拉加载的效果,网上提供了实现这种效果的第三方类(详情请见MJRefresh和  EGOTableViewPullRefresh ),用起来很方便,但是闲暇之余,我们可以思考下,这种效果实现的原理是什么,我以前说过,只要是动画都是骗人的,只要不是硬件问题大部分效果都能在系统UI的基础上做出来.

@下面是关键代码分析:

// 下拉刷新的原理
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView
{if (scrollView.contentOffset.y < - 100) {

  [UIView animateWithDuration:1.0 animations:^{

      //  frame发生偏移,距离顶部150的距离(可自行设定)
      self.tableView.contentInset = UIEdgeInsetsMake(150.0f, 0.0f, 0.0f, 0.0f);
  } completion:^(BOOL finished) {

      /**
       *  发起网络请求,请求刷新数据
       */  }];}
}// 上拉加载的原理
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{NSLog(@"%f",scrollView.contentOffset.y);NSLog(@"%f",scrollView.frame.size.height);NSLog(@"%f",scrollView.contentSize.height);/***  关键-->*  scrollView一开始并不存在偏移量,但是会设定contentSize的大小,所以contentSize.height永远都会比contentOffset.y高一个手机屏幕的*  高度;上拉加载的效果就是每次滑动到底部时,再往上拉的时候请求更多,那个时候产生的偏移量,就能让contentOffset.y + 手机屏幕尺寸高大于这*  个滚动视图的contentSize.height*/if (scrollView.contentOffset.y + scrollView.frame.size.height >= scrollView.contentSize.height) {

  NSLog(@"%d %s",__LINE__,__FUNCTION__);
  [UIView commitAnimations];

  [UIView animateWithDuration:1.0 animations:^{
      //  frame发生的偏移量,距离底部往上提高60(可自行设定)
      self.tableView.contentInset = UIEdgeInsetsMake(0, 0, 60, 0);
  } completion:^(BOOL finished) {

      /**
       *  发起网络请求,请求加载更多数据
       *  然后在数据请求回来的时候,将contentInset改为(0,0,0,0)
       */
  }];}
}