简单实现下拉刷新数据

#import "AppDelegate.h"
#import "SearchController.h"
@interface AppDelegate ()<UITableViewDataSource>
@property (nonatomic,strong)UITableView *table;
@property (nonatomic,strong)NSMutableArray *datas;
@property (nonatomic,strong)UIRefreshControl *refreshControl;
@end

@implementation AppDelegate

- (void)dealloc
{
    self.datas = nil;
    self.table = nil;
    self.refreshControl = nil;
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.backgroundColor = [UIColor whiteColor];


    [self setupViews];
    [self setupWithArray];
    
    [self.window makeKeyAndVisible];
    return YES;
    
}
/**
 *  初始化数组
 */
- (void)setupWithArray
{
    NSArray *array = @[@"A",@"B",@"C",@"D",@"E",@"F"];
    self.datas = [array mutableCopy];
}
/**
 *  添加控件
 */
- (void)setupViews
{
    self.table = [[UITableView alloc] initWithFrame:[[UIScreen mainScreen] bounds] style:UITableViewStylePlain];
    self.table.dataSource = self;
    [self.window addSubview:self.table];
    
    self.refreshControl = [[UIRefreshControl alloc] init];
    [self.refreshControl addTarget:self action:@selector(refreshControlChange:) forControlEvents:UIControlEventValueChanged];
    [self.table addSubview:self.refreshControl];

}

#pragma mark - 配置数据源
/**
 *  @return 返回显示行数
 */
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return self.datas.count;
}
/**
 *  显示内容
 */
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *identify = @"cell";
    UITableViewCell *cell = [self.table dequeueReusableCellWithIdentifier:identify];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identify];
    }
    cell.textLabel.text = self.datas[indexPath.row];
    return cell;
}
/**
 *  每次下拉刷新，就添加新数据
 */
- (void)refreshControlChange:(UIRefreshControl *)sender
{
    static int count = 1;
    NSString *str = [NSString stringWithFormat:@"第%d次加数据",count];
    NSArray *array = @[str];
    NSMutableArray *newArray = [array mutableCopy];
    [newArray addObjectsFromArray:self.datas];
    self.datas = newArray;
    count++;
    /**  UITableView重新加载  */
    [self.table reloadData];
    /**   结束刷新 */
    [self.refreshControl endRefreshing];
}
@end

刷新前                                                 刷新后