UITableView bug in iOS8 when selecting items with estimatedHeight different from rowHeight - ios

Question

I am working on a project that is both iOS7 and iOS8. And I ran into this bug on iOS8, where the tableview will "jump" when selecting an item.
This bug is only there when estimated height is set and it differs from the row height.
Here are two gifs of the same code in iOS8 and iOS7. First iOS8:
And now in iOS7:
I have made a sample project showing the bug here: https://github.com/bjarkehs/TableViewiOS8Bug
I am not sure if I am simply missing something, but I am stuck with this issue and I haven't been able to find anything on this.
Here are my tableView methods:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 3;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if (section == 1) {
return 30;
}
return 20;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"cell"];
}
cell.textLabel.text = [NSString stringWithFormat:#"%# %ld", #"Wat", indexPath.row];
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 45.f;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 50.f;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[self.navigationController pushViewController:[UIViewController new] animated:YES];
}
Here is an example viewcontroller where the calculated height is not hardcoded, showing the same issue:
#import "ViewController.h"
#interface ViewController ()
#property (weak, nonatomic) IBOutlet UITableView *tableView;
#end
#implementation ViewController {
NSMutableArray *_items;
CGFloat _estimatedHeight;
}
- (void)viewDidLoad {
[super viewDidLoad];
self.tableView.delegate = self;
self.tableView.dataSource = self;
_estimatedHeight = 70.f;
CGFloat randomOffset = 30.f;
_items = [NSMutableArray new];
for (NSInteger i = 0; i < 3; i++) {
NSMutableArray *tempItems = [NSMutableArray new];
for (NSInteger j = 0; j < 30; j++) {
NSInteger offset = arc4random_uniform(randomOffset);
[tempItems addObject:#(_estimatedHeight + (randomOffset/2) - offset)];
}
[_items addObject:tempItems];
}
// Do any additional setup after loading the view.
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 3;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if (section == 1) {
return 30;
}
return 20;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"cell"];
}
cell.textLabel.text = [NSString stringWithFormat:#"%# %ld", #"Wat", indexPath.row];
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return _estimatedHeight;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return [[[_items objectAtIndex:indexPath.section] objectAtIndex:indexPath.row] floatValue];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[self.navigationController pushViewController:[UIViewController new] animated:YES];
}
#end

Answer 1

Your implementation for Estimated Height For At Index isn't something I've seen before. Have a look at this where I detailed using this pattern...
Estimated Height Example