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[UITableView]reloadDataの完了後に処理を無理なく行いたい

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やりたかったこと:例

// UITableViewのdataSourceを変更する
……

// dataSource変更後のNSIndexPathを作成する
[NSIndexPath indexPathForRow:row inSection:section];

// 新しいdataSourceに反映させたあとでスクロールさせたい
[_tableView  reloadData]
[_tableView scrollToRowAtIndexPath:indexpath atScrollPosition:UITableViewScrollPositionMiddle animated:YES];

でやってしまうと、scrollToRowAtIndexPathが呼ばれるときは
reloadDataが完了される前のdataSourceで実行されてしまう。
だからといってNSThreadで待ったり、フラグだNotificationだするのはナンセンス

解決方法:UITableViewの拡張

@implementation UITableView (UITableViewAddition)

-(void)reloadDataAndWait:(void(^)(void))waitBlock {
    [self reloadData];
    if(waitBlock){
        waitBlock();
    }
}
@end

使用方法:例

NSLog(@"numberofsection%d",_tableView.numberOfSections);

[_tableView  reloadDataAndWait:^{
    NSLog(@"numberofsection%d",_tableView.numberOfSections);
    [_tableView scrollToRowAtIndexPath:indexpath atScrollPosition:UITableViewScrollPositionMiddle animated:YES];
}];

ちゃんとreload後に処理されていることがわかる。

参考にしたURL
http://stackoverflow.com/questions/15218861/call-function-only-after-reloaddata-has-finished

corocorococoro
100人中5人くらいが嬉しいC#,objective-cのニッチなTipsを投稿出来れば
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