Warning: Attempt to present <MachinesDetailViewController: 0x1e5bfc50> on <UITabBarController: 0x1f867d90> whose view is not in the window hierarchy - window

Question

Im trying to get a scanned QR code to display a view controller with information about the item the code represents. When I try and segue to the detail view controller, it comes up with:
Warning: Attempt to present <MachinesDetailViewController: 0x1e5bfc50> on <UITabBarController: 0x1f867d90> whose view is not in the window hierarchy!
The MainViewController is withing a main tab bar controller, but the detail view controller is within a navigation controller which is withing the tab bar controller.
Heres my MainViewController.m where this is sitting.
//
// FirstViewController.m
// Fitness Plus+
//
// Created by Tom Brereton on 26/01/13.
// Copyright (c) 2013 Tom Brereton. All rights reserved.
//
#import "MainViewController.h"
#import "MachinesDetailViewController.h"
#interface MainViewController ()
#end
#implementation MainViewController
#synthesize resultText, machineKeys, codeInt, machineArea, machineName;
- (IBAction)scanButton:(id)sender {
NSLog(#"ehe");
// ADD: present a barcode reader that scans from the camera feed
ZBarReaderViewController *reader = [[ZBarReaderViewController alloc] init];
reader.readerDelegate = self;
reader.supportedOrientationsMask = ZBarOrientationMaskAll;
ZBarImageScanner *scanner = reader.scanner;
// TODO: (optional) additional reader configuration here
// EXAMPLE: disable rarely used I2/5 to improve performance
[scanner setSymbology: ZBAR_I25
config: ZBAR_CFG_ENABLE
to: 0];
NSLog(#"Got here");
// present and release the controller
[self presentViewController: reader
animated: YES
completion:nil];
}
- (void) imagePickerController: (UIImagePickerController*) reader
didFinishPickingMediaWithInfo: (NSDictionary*) info
{
// ADD: get the decode results
id<NSFastEnumeration> results =
[info objectForKey: ZBarReaderControllerResults];
ZBarSymbol *symbol = nil;
for(symbol in results)
// EXAMPLE: just grab the first barcode
break;
NSLog(#"Naht Here");
// EXAMPLE: do something useful with the barcode data
// Scan the machines.plist array and print it to the console.
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"machines" ofType:#"plist"];
NSDictionary *machineDict = [NSDictionary dictionaryWithContentsOfFile:filePath];
machineKeys = [machineDict objectForKey:#"Exercises"];
machineArea = [machineDict objectForKey:#"Area"];
resultText.text = symbol.data;
//Convert code into integer value and put it inside codeInt
codeInt = [symbol.data intValue];
NSLog(#"Scanned Value: %#", [machineKeys objectAtIndex:codeInt]);
// EXAMPLE: do something useful with the barcode image
[self performSegueWithIdentifier:#"showDetailFromMain" sender:reader];
// ADD: dismiss the controller (NB dismiss from the *reader*!)
[self dismissViewControllerAnimated:YES completion:nil];
}
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)reader {
if ([[segue identifier] isEqualToString:#"showDetailFromMain"]) {
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil];
MachinesDetailViewController *machineViewController = [storyboard instantiateViewControllerWithIdentifier:#"showMachineDetailViewController"];
machineViewController = [segue destinationViewController];
machineName = [machineKeys objectAtIndex:codeInt];
[machineViewController setMachineNameLabel: machineName];
}
}
- (void) viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
The ZBar stuff is just relating to the QR scanning API.
And here is the MachineDetailsViewController.m.
//
// MachinesDetailViewController.m
// Fitness Plus+
//
// Created by Tom Brereton on 27/01/13.
// Copyright (c) 2013 Tom Brereton. All rights reserved.
//
#import "MachinesDetailViewController.h"
#interface MachinesDetailViewController ()
#property(nonatomic, copy) NSString *title;
#end
#implementation MachinesDetailViewController
#synthesize machineLabel, machineName, instructionsLabel, typeLabel, mainMuscleLabel, otherMuscleLabel, equipmentLabel, machineDictionary, machineArray, mainMuscleLabelString, instructionLabelString, typeLabelString, otherMuscleLabelString, equipmentLabelString, title, machineNameLabel;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
// Set the Label text with the selected machine name
machineName = machineNameLabel;
mainMuscleLabel.text = mainMuscleLabelString;
otherMuscleLabel.text = otherMuscleLabelString;
equipmentLabel.text = equipmentLabelString;
typeLabel.text = typeLabelString;
instructionsLabel.text = instructionLabelString;
self.navigationItem.title = machineName;
NSLog(#"got it");
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
Thanks, if you need more info just ask.
Tom

Answer 1

Struggled with the exact same issue,
my solution was to call the segue this way:
[reader dismissViewControllerAnimated:YES completion:^{
NSLog(#"Perform segue");
[self performSegueWithIdentifier:#"showDetailFromMain" sender:self];
}];
I also had to connect the segue to the view and not to a single button.
Hope this works for you.