UITableView UIRefreshControl Does Not Show Its Vie

问题:

I have added the functionality of UIRefreshControl in my project that uses a UITableView. The app works by fetching entries from a web service to a tableview. Below is the code i have used to add UIRefreshControl:

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
    refreshControl.tintColor = [UIColor grayColor];
    refreshControl.attributedTitle = [[NSAttributedString alloc] initWithString:@"Updating New Entries"];
    [refreshControl addTarget:self action:@selector(pullToRefresh) forControlEvents:UIControlEventValueChanged];
    self.refreshControl = refreshControl;

    [self pullToRefresh];    
}

- (void) pullToRefresh
{
    counter = 1;
    [self fetchEntriesNew:counter]; // My code for updating table view

    [self performSelector:@selector(updateTable) withObject:nil afterDelay:2];
}

- (void)updateTable
{
    [self.tableView reloadData];
    [self.refreshControl endRefreshing];
}

Now if i pull to refresh, it refreshes by adding new entries if there are any and shows me the following view on top of the tableview:

Everything works great except when the app is launched or opened for the very first time, it does not show the view that i have showed in the above image, although it does refreshes the tableview. I want it to show the refresh control view every time it refreshes it. Can anyone point out what i am doing wrong? Thanks!

UPDATE: I have added [self refreshControl beginRefreshing] and the UIRefreshControl's spinner view is now showing but its above the first entry of the tableview. Can anyone point out how to correct it?

回答1:

This problem had really puzzled me for a while.I found that 4-inch iOS devices don't have this problem, but 3.5-inch devices do.

I tried to find out the differences between the first time that the refreshControl beginRefreshing itself and when I operated a pull gesture.It's the pull operation.

And I checked Apple's document on UIRefreshControl.It says The control does not initiate the refresh operation directly. Instead, it sends the UIControlEventValueChanged event when a refresh operation should occur.

So I thought maybe I could add something to simulate a pull gesture to trigger refreshControl's showing.

[yourScrollView(or tableView) setContentOffset:CGPointMake(0.0f, -60.0f)
                                      animated:YES];
[yourRefreshControl beginRefreshing];

It works!

PS. UIRefreshControl works with UIScrollView, too. [yourScrollView addSubview:yourRefreshControl] just works.

回答2:

I would move your [self pullToRefresh] call to viewWillAppear instead of viewDidLoad.

回答3:

There are two things that can be done to add UIRefreshControl in your tableview neither of them is added in your code

1. [self setRefreshControl:tableRefreshControl];
2. [self.m_TableView addSubview:tableRefreshControl];

Either add 1 or 2 if your class is subclass of UIViewController

If your class is subclass of UITableViewController then try to replace

self.refreshControl = refreshControl; with 2 line

回答4:

before the code：

[refreshControl beginRefresh]

insert the code：

[refreshControl layoutIfNeeded]