BAD_ACCESS when expanding table view cell using 64-bit iPhone

[jpgupta]

Hi - Love the control, just thought I'd share an issue that took me a while to figure out! Unfortunately I don't really know how to solve it but hopefully it'll help

When compiling with the "Standard Architectures + 64 bit" setting on my iPhone 5S, it crashes with a BAD_ACCESS exception when expanding a table view cell.

It occurs on SKSTableView.m line 705 (the objc_setAssociatedObject call in setSubRow: )

The problem, as far as I can see, is that under 64 bit architectures the subRowObj is being treated as a long instead of an int (which it is on 32 bit) as shown below

I've changed my project settings to exclude 64 bit architectures (as in the sample app you provided) and its working fine now

[sakkaras]

Thanks for the issue, i did not test the control for the 64-bit devices, my bad. But i will check the issue and fix the problem.

[martinr448]

See http://stackoverflow.com/a/21562526/1187415 for an analysis of the problem and a possible solution for 64-bit mode.

[sakkaras]

I temporarily fixed the issue by setting the subRow property as NSString not NSNumber. The explanation in the stackoverflow question helped me much, thank you. I will close this issue for now, but this problem will be in my mind.

[martinr448]

The bug is not fixed. It still crashes on 64-bit.

The problem is not that subRow is a NSNumber. The problem is that NSIndexPath ("self" in the setSubRow: method) is possibly a "tagged pointer" and setting an associated object on a tagged pointer crashes.

[sakkaras]

I may understand the problem wrong. However, i test the table in 64-bit iPhone simulator, it works fine. So, i considered it as resolved. You try it in simulator or the real device?

[martinr448]

I tested it in the 64-bit iPhone Simulator, and it crashes immediately if you expand a row. I changed the build architectures to "Standard Architectures (including 64-bit)" first, otherwise it is compiled for 32-bit only. - I cloned your repository and will try to check-in my fix. But I am still new to git and github, so this may take some time ...

[sakkaras]

Sorry about my answer, i forgot to change the build architecture (it does not include 64-bit). So, the problem does still exists.

[widmore]

Is it resolved?

[tufnica]

ok guys , there is simple and elegant solution to solve this :)
little explanation :
On iOS for arm64, the isa field of Objective-C objects is no longer a pointer.
Some of the bits still encode the pointer to the object's class. But neither OS X nor iOS actually uses all 64 bits of virtual address space. The Objective-C runtime may use these extra bits to store per-object data like its retain count or whether it has been weakly referenced.
They changed "this" to 64bit becouse performance. Re-purposing these otherwise unused bits increases speed and decreases memory size. On iOS 7 the focus is on optimizing retain/release and alloc/dealloc.
from that REASON DON'T

1. read obj->isa directly. The compiler will complain if you do. Trust the Compiler. The Compiler is your friend. Use [obj class] or object_getClass(obj) instead.
   2.Don't write obj->isa directly. Use object_setClass() instead.

from that reason you need to change "way" you setting in 2 methods .
example .

• (NSInteger)subRow
  {
  id myclass = [SKSTableView class];

  id subRowObj = objc_getAssociatedObject(myclass, SubRowObjectKey);
  return [subRowObj integerValue];
  }

• (void)setSubRow:(NSInteger)subRow
  {
  id subRowObj = [NSNumber numberWithInteger:subRow];

  id myclass = [SKSTableView class];

  objc_setAssociatedObject(myclass, nil, subRowObj, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

}
so put example for setSubRow and subRow , id myclass = [SKSTableView class];
objc_getAssociatedObject(myclass, SubRowObjectKey);
and
for objc_setAssociatedObject(myclass, nil, subRowObj, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

self-->isa IS PROBLEM on arm64 on iOS .

This works for 32bits and 64bit arch :)

[devil9677]

thank u so much this solve my problem in 64 bit and 32 bit

[devil9677]

love u boss solved my problem

[pradeepramalingam]

even after replacing the code I've got the same issue! any other solutions?

[mjspawn]

The code works for me

[Lorwy]

Thank u so much this solve my crash in iOS7.x

[kirti301290]

Hi
i am using this control is works fins but facing one issue i have added one button in cellForSubRowAtIndexPath when i clicked button the i got wrong row and subrow below is mu code

• (UITableViewCell )tableView:(UITableView *)tableView cellForSubRowAtIndexPath:(NSIndexPath *)indexPath
  {
  UIButton *btn=(UIButton)[cell.contentView viewWithTag:15];
  [btn addTarget:self action:@selector(DeleteClicked:) forControlEvents:UIControlEventTouchUpInside];
  }
  -(void)DeleteClicked:(UIButton*)sender
  {
  CGPoint point=[sender convertPoint:CGPointZero toView:tbl_Preview];
  indexpath=[tbl_Preview indexPathForRowAtPoint:point];
  // i got wrong indexpath
  }

[AresDev]

Same problem in iOS7 and it worked, Thks!