加载数据后立即显示tableView popover [英] Show tableView popover as soon as data is loaded

问题描述

我想从一开始就显示一个TableView的Popover，当应用程序加载时。问题是tableView没有任何内容。我正在使用该方法：

i want to show a my Popover with a TableView just from the beginning, when the app loads. Problem is that the tableView doesn't have any content then. I am using that method:

 UIBarButtonItem *barItem = [self.toolbar.items objectAtIndex:0];
[self.popoverController presentPopoverFromBarButtonItem:barItem permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];

现在，我的想法是在tableView完成数据获取时触发一个委托方法，但不幸的是没有任何事情发生：

Now, my idea was to have a delegate method which is fired when the tableView finished fetching the data, but unfortunately nothing happens:

RootViewController.h ：

@protocol RootDelegate <NSObject>
@optional
 -(void)didFinishLoading;
@end

RootViewController.m ：

- (void)viewDidLoad
{
[super viewDidLoad];
[self.tableView initWithFrame:self.tableView.frame style:UITableViewStyleGrouped];
self.clearsSelectionOnViewWillAppear = NO;
[self setTitle:@"Zielscheiben"];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(dataSaved:) name:@"DataSaved" object:nil];

[[self delegate] didFinishLoading];
}

DetailViewController.m （符合协议）

 - (void)didFinishLoading
 {
    UIBarButtonItem *barItem = [self.toolbar.items objectAtIndex:0];
    [self.popoverController presentPopoverFromBarButtonItem:barItem permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];

  }

推荐答案

视图方法是线程化的，所以在viewDidLoad的末尾调用会发生在不可预测的时间，显然在这之前，表被填满。我看不到任何委托方法引用事件表已填满，所以我最好的猜测是保留代码并延迟其执行：

The table view methods are threaded so your call at the end of viewDidLoad will happen at an unpredictable time, apparently here before the table is filled. I can't see any delegate method refering to the event "table is filled", so my best guess would be to keep your code and delay its execution :

[[self delegate] performSelector:@selector(didFinishLoading) withObject:nil afterDelay:1]

假设1秒将足以使表被填充。

assuming 1 second will be enough for the table to be filled.

您可以探索的另一个选项是在cellForRowAtIndexPath中的某个时间点火，当您计算表已经有足够的数据，但这在某种程度上更复杂。

Another option you could explore is to fire it sometime in cellForRowAtIndexPath when you reckon the table has got enough data, but this is somehow more complex.

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