How to tell when UITableView has completed ReloadD

2019-01-01 11:57发布

I am trying to scroll to the bottom of a UITableView after it is done performing [self.tableView reloadData]

I originally had

 [self.tableView reloadData]
 NSIndexPath* indexPath = [NSIndexPath indexPathForRow: ([self.tableView numberOfRowsInSection:([self.tableView numberOfSections]-1)]-1) inSection: ([self.tableView numberOfSections]-1)];

[self.tableView scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionBottom animated:YES];

But then I read that reloadData is asynchronous, so the scrolling doesn't happen since the self.tableView, [self.tableView numberOfSections] and [self.tableView numberOfRowsinSection are all 0.

Thanks!

What's weird is that I am using:

[self.tableView reloadData];
NSLog(@"Number of Sections %d", [self.tableView numberOfSections]);
NSLog(@"Number of Rows %d", [self.tableView numberOfRowsInSection:([self.tableView numberOfSections]-1)]-1);

In the console it returns Sections = 1, Row = -1;

When I do the exact same NSLogs in cellForRowAtIndexPath I get Sections = 1 and Row = 8; (8 is right)

14条回答
怪性笑人.
2楼-- · 2019-01-01 12:37

Actually this one solved my problem:

-(void) tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {

NSSet *visibleSections = [NSSet setWithArray:[[tableView indexPathsForVisibleRows] valueForKey:@"section"]];
if (visibleSections) {
    // hide the activityIndicator/Loader
}}
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路过你的时光
3楼-- · 2019-01-01 12:42

I use this trick, pretty sure I already posted it to a duplicate of this question:

-(void)tableViewDidLoadRows:(UITableView *)tableView{
    // do something after loading, e.g. select a cell.
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // trick to detect when table view has finished loading.
    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(tableViewDidLoadRows:) object:tableView];
    [self performSelector:@selector(tableViewDidLoadRows:) withObject:tableView afterDelay:0];

    // specific to your controller
    return self.objects.count;
}
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