Swift ios 9: Section header change position after

Question

I have plain UITableView with many sections and rows. Sections work fine. But sometimes after reload data of table, section change position. For example it was happened when i change tabs. What could be the problem?

Image before changed tabs:

Image after changed tabs:

Update: Add code below:

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    self.dishesListTableView.reloadData()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}


func customizeCollectionView() {
    self.collectionView.delegate = self
    self.collectionView.dataSource = self
    self.collectionView.dataProviderDelegate = self.dishesListDataProvider
    self.collectionView.showsHorizontalScrollIndicator = false
    self.collectionView.decelerationRate = UIScrollViewDecelerationRateFast
    self.collectionView.registerClass(HPCollectionViewCell.self, forCellWithReuseIdentifier: HPCollectionViewCellConstants.reuseIdentifier)
}

//MARK: - UITableViewDelegate
func customziseDishesListTableView(){
    self.dishesListTableView.delegate = self
    self.dishesListTableView.dataSource = self

    self.dishesListTableView.registerNib(UINib(nibName: DishesListSingleTableViewCell.nibName, bundle: nil), forCellReuseIdentifier: DishesListSingleTableViewCell.nibName)
    self.dishesListTableView.registerNib(UINib(nibName: DishesListSinglePizzaTableViewCell.nibName, bundle: nil), forCellReuseIdentifier: DishesListSinglePizzaTableViewCell.nibName)

    self.dishesListTableView.estimatedRowHeight = 123
    self.dishesListTableView.rowHeight = UITableViewAutomaticDimension

    if self.dishesListDataProvider.isPizza() {
        self.dishesListTableView.separatorColor = UIColor.clearColor()
    }else{
        self.dishesListTableView.separatorColor = UIColor.expSilverColor()
    }
}

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return self.dishesListDataProvider.countOfDishes(section)
}

func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    return self.dishesListDataProvider.countOfKitchenTypes()
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    if self.dishesListDataProvider.getDishItemByIndex(indexPath.section, indexDish: indexPath.row).isPizza() {
        let cell = tableView.dequeueReusableCellWithIdentifier(DishesListSinglePizzaTableViewCell.nibName, forIndexPath: indexPath) as! DishesListSinglePizzaTableViewCell
        cell.customizeView(self.dishesListDataProvider.getDishItemByIndex(indexPath.section, indexDish: indexPath.row), dishesListSingleTableViewCellProtocol: self, indexPath: indexPath)
        return cell
    }else{
        let cell = tableView.dequeueReusableCellWithIdentifier(DishesListSingleTableViewCell.nibName, forIndexPath: indexPath) as! DishesListSingleTableViewCell

        cell.customizeView(self.dishesListDataProvider.getDishItemByIndex(indexPath.section, indexDish: indexPath.row), dishesListSingleTableViewCellProtocol: self, indexPath: indexPath)
        return cell
    }
}

func tableView(tableView: UITableView, willDisplayFooterView view: UIView, forSection section: Int) {
    self.collectionView.scrollToIndex(section, animated: true)
    self.collectionView.changeSelectionForCellAtIndexPath(NSIndexPath(forItem: section, inSection: 0))
}

func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
    let sectionView = NSBundle.mainBundle().loadNibNamed(DishesListSectionView.nibName, owner: self, options: nil)[0] as! DishesListSectionView

    sectionView.customizeView(self.dishesListDataProvider.getKitchenItemByIndex(section).kitchenTypeTitle)

    return sectionView
}
//MARK: - UIScrollViewDelegate
func scrollViewDidScroll(scrollView: UIScrollView) {
    if currentSectionIndex != self.dishesListTableView.indexPathsForVisibleRows![0].section {
        currentSectionIndex = self.dishesListTableView.indexPathsForVisibleRows![0].section
        self.collectionView.scrollToIndex(currentSectionIndex, animated: true)
        self.collectionView.changeSelectionForCellAtIndexPath(NSIndexPath(forItem: currentSectionIndex, inSection: 0))
    }

}

Answer 1

I know it's an old thread but uncheck the Adjust Scroll View Insets doesn't help. I had this problem and solved it by reload table twice.

Answer 2

The solutions here didn't fix my problem, so I'm leaving one more possible solution that helped me.

Set the estimatedSectionHeaderHeight, it seems that my tableView wasn't being able to calculate the initial position of my first section without it.

Answer 3

In my project ,this error happened when i pull up tableView to request more data then reload the data after requesting. I need create many sections after requesting the data and it may effect the performance if i reloadData twice. More than, i found that if i scroll up or down the tableView, the position of section's headerView get right. So i fix this bug(my condition) i requesting the data by this:

[_tableView reloadData];
CGPoint offSetOrigin     = _tableView.contentOffset;
CGPoint offSetSecond     = CGPointMake(0, offSet.y-1);
_tableView.contentOffset = offSetSecond;
_tableView.contentOffset = offSet;

Answer 4

This is because of UI viewcontroller property. Please first select UIViewController From Storyboard , Attribute Inspector

Answer 5

Calling reloadData() twice also works for me, but I would suggest calling tableView.layoutSubviews() after reloadData(), which also works for me.

Answer 6

tableView.reloadData()
tableView.layoutIfNeeded()
tableView.beginUpdates()
tableView.endUpdates()

This help me out.

Double reloadData will cause flickering while this solution won't.