我有一个包含用户帖子的tableview。每个帖子都有一张图片,用户名和帖子本身。刷新控件的操作是使用来自Parse的数据重新加载表。一切都很完美,除了我拉动刷新时的极端延迟。我不知道是不是因为每个单元格中的图片或其他内容。如果有人知道为什么会这样,请告诉我。如果有人需要,我会发布代码。
-(void)viewDidLoad {
refreshControl = [[UIRefreshControl alloc] init];
[refreshControl addTarget:self action:@selector(retrieveFromParse) forControlEvents:UIControlEventValueChanged];
refreshControl.backgroundColor = [UIColor whiteColor];
refreshControl.tintColor = [UIColor colorWithRed:0.3878 green:0.5686 blue:1.0 alpha:0.9];
[userPostsTable addSubview:refreshControl];
}
-(void) retrieveFromParse {
PFQuery *quoteQuery = [PFQuery queryWithClassName:@"Quotes"];
quoteQuery.cachePolicy = kPFCachePolicyCacheThenNetwork;
[quoteQuery orderByDescending:@"createdAt"];
[quoteQuery getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) {
if (!error) {
NSString *category = [object objectForKey:@"Category"];
if (category == nil) {
quoteLabel.font = [UIFont fontWithName:@"Helvetica Neue Light Italic" size:15];
}
else {
quoteLabel.font = [UIFont fontWithName:@"Helvetica Neue" size:15];
}
quoteString = [object objectForKey:@"quoteContent"];
quoteLabel.text = quoteString;
quoteIdString = object.objectId;
[refreshControl endRefreshing];
}
else {
[refreshControl endRefreshing];
}
}];
PFQuery *userPostsQuery = [PFQuery queryWithClassName:@"userPosts"];
userPostsQuery.cachePolicy = kPFCachePolicyCacheThenNetwork;
[userPostsQuery setLimit:300];
[userPostsQuery whereKey:@"quoteObjectId" matchesKey:@"objectId" inQuery:quoteQuery];
if (segmentedControl.selectedSegmentIndex == 0) {
[userPostsQuery orderByDescending:@"createdAt"];
}
else {
[userPostsQuery orderByDescending:@"likeCount"];
}
[userPostsQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (!error) {
userPostsArray = [[NSArray alloc] initWithArray:objects];
[userPostsTable reloadData];
[refreshControl endRefreshing];
}
else {
[refreshControl endRefreshing];
}
}];
}
答案 0 :(得分:1)
您正在后台线程中检索对象。
getFirstObjectInBackgroundWithBlock:
此外,您正在尝试从后台线程更新UI。您只需要从主线程更新UI:
调用所有与UI相关的调用,如:
[userPostsTable reloadData];
[refreshControl endRefreshing];
仅限主线。
使用:
dispatch_async(dispatch_get_main_queue(), ^{
// Update UI
});
答案 1 :(得分:0)
假设您的代码段是UITableViewController
的一部分,则不应将refreshControl
添加为subview
的{{1}}。
tableView