iOS开发教程之UIRefreshControl使用的踩坑指南

- (void) loadRefreshView
{
 // 下拉刷新
 _refreshControl = [[UIRefreshControl alloc] init];
 _refreshControl.attributedTitle = [[NSAttributedString alloc] initWithString:@"下拉刷新"];
 [_refreshControl addTarget:self action:@selector(loadData) forControlEvents:UIControlEventValueChanged];
 [self.securityCollectionView addSubview:_refreshControl];
 [self.securityCollectionView sendSubviewToBack:_refreshControl];
}

// 设置刷新状态
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
 decelerate = YES;
 if (scrollView.contentOffset.y < HEIGHT_REFRESH) {
  dispatch_async(dispatch_get_main_queue(), ^{
   _refreshControl.attributedTitle = [[NSAttributedString alloc] initWithString:@"正在刷新"];
  });
  [_refreshControl beginRefreshing];
  [self loadData];
 }
}

// 设置刷新状态
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
 if (scrollView.contentOffset.y >= HEIGHT_REFRESH) {
  _refreshControl.attributedTitle = [[NSAttributedString alloc] initWithString:@"下拉刷新"];
 }
 else if (!scrollView.decelerating) {
  _refreshControl.attributedTitle = [[NSAttributedString alloc] initWithString:@"松开刷新"];
 }
}

// 结束刷新
- (void) endRefreshControl
{
 [_refreshControl endRefreshing];
}

// 刷新的回调方法
- (void) loadData
{
 [self endRefreshControl];
 // [self performSelector:@selector(endRefreshControl) withObject:nil afterDelay:2];
}

//设置如果collection的内容没有占满整个collectionView，
//这个就不能下拉滑动，没法实现下拉；但是设置下面这个就可以实现下拉了
self.rootView.collectionView.alwaysBounceVertical = YES;

UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
refreshControl.tintColor = [UIColor grayColor];
refreshControl.attributedTitle = [[NSAttributedString alloc] initWithString:@"下拉刷新"];
[refreshControl addTarget:self action:@selector(refreshTabView) forControlEvents:UIControlEventValueChanged];
self.newsTableView.refreshControl = refreshControl;

-(void)refreshTabView
{
//添加一条数据
[self.newsData insertObject:[self.newsData firstObject] atIndex:0];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[self.newsTableView reloadData];
if ([self.newsTableView.refreshControl isRefreshing]) {
[self.newsTableView.refreshControl endRefreshing];
}
});
}

-(void)doubleClickTab:(NSNotification *)notification{
//这里有个坑 就是直接用NSInteger接收会有问题 数字不对
//因为上个界面传过来的时候封装成了对象，所以用NSNumber接收后再取值
NSNumber *index = notification.object;
if ([index intValue] == 1) {
//刷新
[self.newsTableView.refreshControl beginRefreshing];
}
}

-(void)doubleClickTab:(NSNotification *)notification{
//这里有个坑 就是直接用NSInteger接收会有问题 数字不对
//因为上个界面传过来的时候封装成了对象，所以用NSNumber接收后再取值
NSNumber *index = notification.object;
if ([index intValue] == 1) {
//刷新
//animated不要为YES，否则菊花会卡死
[self.newsTableView setContentOffset:CGPointMake(0, self.newsTableView.contentOffset.y - self.newsTableView.refreshControl.frame.size.height) animated:NO];
[self.newsTableView.refreshControl beginRefreshing];
[self.newsTableView.refreshControl sendActionsForControlEvents:UIControlEventValueChanged];
}
}