如何在IOS开发中表视图的下拉刷新控制

#import "ViewController.h" 
 @interface ViewController () 
@end 
@implementation ViewController 
- (void)viewDidLoad { 
 [super viewDidLoad]; 
 self.Logs = [[NSMutableArray alloc]init];//初始化数据 
 NSDate * date = [[NSDate alloc]init];//初始化日期 
 [self.Logs addObject:date];//把日期插入数据中 
 UIRefreshControl * rc = [[UIRefreshControl alloc]init];//初始化UIRefreshControl 
 rc.attributedTitle = [[NSAttributedString alloc]initWithString:@"下拉刷新"];//设置下拉框控件标签 
 [rc addTarget:self action:@selector(refreshAction) forControlEvents:UIControlEventValueChanged];//添加下拉刷新事件 
 self.refreshControl = rc; 
 // Do any additional setup after loading the view, typically from a nib. 
} 
- (void)didReceiveMemoryWarning { 
 [super didReceiveMemoryWarning]; 
 // Dispose of any resources that can be recreated. 
} 
//下拉刷新事件 
-(void)refreshAction 
{ 
 if(self.refreshControl.refreshing) 
 { 
  self.refreshControl.attributedTitle = [[NSAttributedString alloc]initWithString:@"加载中"];//设置下拉框控件标签 
  NSDate * date = [[NSDate alloc]init]; 
  [self.Logs addObject:date];//每次刷新添加当前日期 
  [self.refreshControl endRefreshing];//结束刷新 
  self.refreshControl.attributedTitle = [[NSAttributedString alloc]initWithString:@"下拉刷新"]; 
  [self.tableView reloadData]; 
 } 
} 
#pragma mark 
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView 
{ 
 return 1; 
} 
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 
{ 
 return [self.Logs count]; 
} 
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
 UITableViewCell * Cell = [tableView dequeueReusableCellWithIdentifier:@"cell"]; 
 NSDateFormatter * dateFormat =[[NSDateFormatter alloc]init];//NSDate的转换类，可将NSDate转换为其它格式，或者转换为NSDate格式 
 [dateFormat setDateFormat:@"yyyy-MM-dd HH:mm:ss zzz"];//设定时间格式 
 Cell.textLabel.text = [dateFormat stringFromDate:[self.Logs objectAtIndex:indexPath.row]]; 
 Cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator; 
 return Cell; 
} 
@end