使用UIRefreshControl

应用中用到UIRefreshControl。

遇到一些问题，请大神解答。

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.searchDisplayController.delegate = self;
    UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
    [refreshControl addTarget:self action:@selector(refresh:) forControlEvents:UIControlEventValueChanged];
    [self.rearTableView addSubview:refreshControl];
}
- (void)refresh:(UIRefreshControl *)refreshControl {
    [refreshControl beginRefreshing];
    [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(endRefresh:) userInfo:nil repeats:NO];
}
- (void)endRefresh:(UIRefreshControl *)refresh
{
    [refresh endRefreshing];
}

拖拽tableView会初始化计时器，但是提前2秒。然后应用就崩溃了：
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFTimer endRefreshing]: unrecognized selector sent to instance 0x9c093c0'

NSTimer的处理selector中的方法命名不妥。改成

[NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(endRefresh) userInfo:nil repeats:NO];

- (void)endRefresh
{
    [refresh endRefreshing];
}

将refreshControl在头文件中定义成成员变量。

问题出在这里：

[NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(endRefresh:) userInfo:nil repeats:NO];

你添加了endRefresh作为计数器的selector。因此endRefresh的参数应该是一个NSTimer ，而不是UIRefreshControl

解决方法1 ：

将UIRefreshControl 作为property声明。

解决方法2 ：

修改方法如下：

- (void)refresh:(UIRefreshControl *)refreshControl
{
    [refreshControl beginRefreshing];
    [self performSelector:@selector(endRefresh:) withObject:refreshControl afterDelay:2.0f];
}

- (void)endRefresh:(UIRefreshControl *)refresh
{
    [refresh performSelectorOnMainThread:@selector(endRefreshing) withObject:nil waitUntilDone:NO];
}