Auto layout on UITableViewHeader

Question

I've filed a bug report with Apple about this issue!

I'm trying to use the new iOS 6 Auto Layout on my UITableViewHeader, but everything I throw at it comes back with the error at the end of the post.

My code:

TBMTableViewController.h

#import <UIKit/UIKit.h>

@interface TBMTableViewController : UIViewController <UITableViewDataSource, UITableViewDelegate>

@end

TBMTableViewController.m

#import "TBMTableViewController.h"
#import "UIView+Constraint.h"

@implementation TBMTableViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    UITableViewController *tableViewController = [[UITableViewController alloc] initWithStyle:UITableViewStylePlain];
    [tableViewController.tableView setTranslatesAutoresizingMaskIntoConstraints:NO];

    UITableView *tableView = tableViewController.tableView;
    [tableView setTranslatesAutoresizingMaskIntoConstraints:NO];
    [tableView setDelegate:self];
    [tableView setDataSource:self];

    [self.view addSubview:tableView];

    UIView *headerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 200.0f)];
    [headerView setTranslatesAutoresizingMaskIntoConstraints:NO];
    [tableView setTableHeaderView:headerView];

    UIButton *btn1 = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [btn1 setTranslatesAutoresizingMaskIntoConstraints:NO];
    [btn1 setTitle:@"Button 1" forState:UIControlStateNormal];
    [btn1 sizeToFit];
    [headerView addSubview:btn1];

    UIButton *btn2 = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [btn2 setTranslatesAutoresizingMaskIntoConstraints:NO];
    [btn2 setTitle:@"Button 2" forState:UIControlStateNormal];
    [btn2 sizeToFit];
    [headerView addSubview:btn2];

    NSDictionary *views = NSDictionaryOfVariableBindings(tableView, headerView, btn1, btn2);

    [self.view addVisualConstraints:@"H:|[tableView]|" forViews:views];
    [self.view addVisualConstraints:@"V:|[tableView]|" forViews:views];

    [headerView addVisualConstraints:@"H:[btn1]-|" forViews:views];
    [headerView addVisualConstraints:@"V:|-[btn1]" forViews:views];
    [headerView addVisualConstraints:@"H:[btn2]-|" forViews:views];
    [headerView addVisualConstraints:@"V:[btn1]-[btn2]" forViews:views];
    [headerView addVisualConstraints:@"[btn2(==btn1)]" forViews:views];
}

@end

UIView+Constraint.m

- (void)addVisualConstraints:(NSString *)constraintString forViews:(NSDictionary *)views {
    [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:constraintString
                                                                 options:0
                                                                 metrics:0
                                                                   views:views]];
}

Error:

2013-02-01 00:43:34.481 ConstraintTest[10217:c07] *** Assertion failure in 
-[UITableView layoutSublayersOfLayer:], 
/SourceCache/UIKit_Sim/UIKit-2380.17/UIView.m:5776
2013-02-01 00:43:34.483 ConstraintTest[10217:c07] *** Terminating app due to 
uncaught exception 'NSInternalInconsistencyException', reason: 'Auto Layout still 
required after executing -layoutSubviews. UITableView's implementation of  
-layoutSubviews needs to call super.'

*** First throw call stack:
(0x1c94012 0x10d1e7e 0x1c93e78 0xb67665 0x6639f 0x10e56b0 0x2290fc0 0x228533c  
0x2290eaf 0x1052bd 0x4db56 0x4c66f 0x4c589 0x4b7e4 0x4b61e 0x4c3d9 0x4f2d2  
0xf999c 0x46574 0x4676f 0x46905 0x4f917 0x2b15 0x13157 0x13747 0x1494b 0x25cb5  
0x26beb 0x18698 0x1befdf9 0x1befad0 0x1c09bf5 0x1c09962 0x1c3abb6 0x1c39f44  
0x1c39e1b 0x1417a 0x15ffc 0x28dd 0x2805)
libc++abi.dylib: terminate called throwing an exception
(lldb)

I've tried everything I can think of. Even Google wasn't helpful in providing an answer. I've removed the non-pertinent code such as UITableViewDataSource- and UITableViewDelegate methods for clarification. There are no nibs involved and the only thing my appDelegate does is init the TBMTableViewController and setting it as the rootViewController.

Edit: I've updated my viewDidLoad method to clarify that I want to use constraints on controls inside the UITableViewHeader, not the header itself. Same error :)

Solution

This turned out to be a really stupid error on my part. I eventually got everything working when I removed the lines:

[tableView setTranslatesAutoresizingMaskIntoConstraints:NO];

and

[headerView setTranslatesAutoresizingMaskIntoConstraints:NO];

Comments

[Lee Probert]

although this solves your problem it does raise an important question about this line of code : how the hell do you use this code to stop ambigious layout problems!?!

[A'sa Dickens]

[headerView layoutSubviews]; call that when you call addSubview

[David H]

Just for the record, I'm doing all my header in code, and using NSLayoutContraint objects. It was the second statement above that stopped my crash in iOS7.