iOS app crashes when sending text from one ViewController to the another - ios

Question

I want to send the text that a user inputs into the itemSearch UITextField in the SearchViewController over to MatchCenterViewController, so that it can use it in a function.
I've made the itemSearch property public by placing its IBOutlet in SearchViewController's header. It doesn't seem to send over successfully during the segue however, as it crashes when the eBayMatchCenterSearch function runs during the ShowMatchCenterSegue.
Error message:
2014-05-21 15:47:17.785 Parse+Storyboard[8787:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSPlaceholderDictionary initWithObjects:forKeys:count:]: attempt to insert nil object from objects[0]'
*** First throw call stack:
(
0 CoreFoundation 0x02a881e4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x026468e5 objc_exception_throw + 44
2 CoreFoundation 0x02a4e376 -[__NSPlaceholderDictionary initWithObjects:forKeys:count:] + 390
3 CoreFoundation 0x02a7bc29 +[NSDictionary dictionaryWithObjects:forKeys:count:] + 73
4 Parse+Storyboard 0x00004c09 -[MatchCenterViewController viewDidLoad] + 329
5 UIKit 0x0142533d -[UIViewController loadViewIfRequired] + 696
6 UIKit 0x014255d9 -[UIViewController view] + 35
7 UIKit 0x0143f942 -[UINavigationController _startCustomTransition:] + 778
8 UIKit 0x0144c8f7 -[UINavigationController _startDeferredTransitionIfNeeded:] + 688
9 UIKit 0x0144d4e9 -[UINavigationController __viewWillLayoutSubviews] + 57
10 UIKit 0x0158e0d1 -[UILayoutContainerView layoutSubviews] + 213
11 UIKit 0x01375964 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 355
12 libobjc.A.dylib 0x0265882b -[NSObject performSelector:withObject:] + 70
13 QuartzCore 0x0064b45a -[CALayer layoutSublayers] + 148
14 QuartzCore 0x0063f244 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 380
15 QuartzCore 0x0063f0b0 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 26
16 QuartzCore 0x005a57fa _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 294
17 QuartzCore 0x005a6b85 _ZN2CA11Transaction6commitEv + 393
18 QuartzCore 0x005a7258 _ZN2CA11Transaction17observer_callbackEP19__CFRunLoopObservermPv + 92
19 CoreFoundation 0x02a5036e __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 30
20 CoreFoundation 0x02a502bf __CFRunLoopDoObservers + 399
21 CoreFoundation 0x02a2e254 __CFRunLoopRun + 1076
22 CoreFoundation 0x02a2d9d3 CFRunLoopRunSpecific + 467
23 CoreFoundation 0x02a2d7eb CFRunLoopRunInMode + 123
24 GraphicsServices 0x02ce55ee GSEventRunModal + 192
25 GraphicsServices 0x02ce542b GSEventRun + 104
26 UIKit 0x01306f9b UIApplicationMain + 1225
27 Parse+Storyboard 0x00002b0d main + 141
28 libdyld.dylib 0x038e2701 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
SearchViewController.h:
#import <UIKit/UIKit.h>
#import <Parse/Parse.h>
#import <Parse/PFCloud.h>
#import "CriteriaViewController.h"
#interface SearchViewController : UIViewController
#property (weak, nonatomic) IBOutlet UIButton *nextButtonOutlet;
#property (nonatomic, copy) NSString *topCategory1;
#property (nonatomic, copy) NSString *topCategory2;
#property (nonatomic, copy) NSNumber *topCategoryId1;
#property (nonatomic, copy) NSNumber *topCategoryId2;
#property (weak, nonatomic) IBOutlet UITextField *itemSearch;
#end
SearchViewController.m:
#import "SearchViewController.h"
#import "MatchCenterViewController.h"
#import "SearchCategoryChooserViewController.h"
#interface SearchViewController ()
#property (weak, nonatomic) IBOutlet UIButton *nextButton;
#end
#implementation SearchViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
[self.nextButtonOutlet addTarget:self action:#selector(nextButton:) forControlEvents:UIControlEventTouchUpInside];
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)nextButton:(id)sender
{
if (self.itemSearch.text.length > 0) {
[PFCloud callFunctionInBackground:#"eBayCategorySearch"
withParameters:#{#"item": self.itemSearch.text}
block:^(NSDictionary *result, NSError *error) {
NSLog(#"'%#'", result);
// Parses results
NSArray *resultArray = [result objectForKey:#"results"];
// Number of Top Categories
NSDictionary *dictionary0 = [resultArray objectAtIndex:0];
NSNumber *numberOfTopCategories = [dictionary0 objectForKey:#"Number of top categories"];
// Ids of the Top Categories
NSDictionary *dictionary1 = [resultArray objectAtIndex:1];
NSArray *topCategoryIdsArray = [dictionary1 objectForKey:#"Top category Ids"];
// Names of the Top Categories
NSDictionary *dictionary2 = [resultArray objectAtIndex:2];
NSArray *topCategoryNamesArray = [dictionary2 objectForKey:#"Top category names"];
// Number of Top Categories matching User Categories
NSDictionary *dictionary3 = [resultArray objectAtIndex:3];
NSNumber *numberOfMatches = [dictionary3 objectForKey:#"Number of matches"];
// Names of Top Categories matching User Categories
NSDictionary *dictionary4 = [resultArray objectAtIndex:4];
NSArray *userCategoriesThatMatchSearch = [dictionary4 objectForKey:#"User categories that match search"];
// Defines where each topCategory name will come from
self.topCategory1 = [topCategoryNamesArray objectAtIndex:0];
if ([numberOfTopCategories intValue] == 2) {
self.topCategory2 = [topCategoryNamesArray objectAtIndex:1];
}
// Defines where each topCategory ID will come from
self.topCategoryId1 = [topCategoryIdsArray objectAtIndex:0];
if ([numberOfTopCategories intValue] == 2) {
self.topCategoryId2 = [topCategoryIdsArray objectAtIndex:1];
}
if (!error) {
// Decides which segue is taken based on results
// if 1 match found clear categoryResults and top2 array
if ([numberOfMatches intValue] == 1 ){
[self performSegueWithIdentifier:#"ShowMatchCenterSegue" sender:self];
}
// if 2 matches found
else if ([numberOfMatches intValue] == 2){
[self performSegueWithIdentifier:#"ShowUserCategoryChooserSegue" sender:self];
//default to selected categories criteria -> send to matchcenter -> clear categoryResults and top2 array
}
// if no matches found, and 1 top category is returned
else if ([numberOfMatches intValue] == 0 && [numberOfTopCategories intValue] == 1) {
[self performSegueWithIdentifier:#"ShowCriteriaSegue" sender:self];
}
// if no matches are found, and 2 top categories are returned
else if ([numberOfMatches intValue] == 0 && [numberOfTopCategories intValue] == 2) {
[self performSegueWithIdentifier:#"ShowSearchCategoryChooserSegue" sender:self];
}
}
}];
}
}
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([segue.identifier isEqualToString:#"ShowMatchCenterSegue"]) {
MatchCenterViewController *controller = (MatchCenterViewController *) segue.destinationViewController;
// Send over the search query
controller.itemSearch.text = self.itemSearch.text;
}
else if([segue.identifier isEqualToString:#"ShowSearchCategoryChooserSegue"]){
SearchCategoryChooserViewController *controller = (SearchCategoryChooserViewController *) segue.destinationViewController;
// Send over the search query as well as both categories to the Category Chooser VC
controller.itemSearch.text = self.itemSearch.text;
controller.topCategory1 = self.topCategory1;
controller.topCategory2 = self.topCategory2;
controller.topCategoryId1 = self.topCategoryId1;
controller.topCategoryId2 = self.topCategoryId2;
}
else if([segue.identifier isEqualToString:#"ShowCriteriaSegue"]){
CriteriaViewController *controller = (CriteriaViewController *) segue.destinationViewController;
// Send over the search query as well as the specific category to CriteriaVC to use
controller.itemSearch = self.itemSearch.text;
controller.chosenCategory = self.topCategoryId1;
}
}
#end
MatchCenterViewController.h:
#import <UIKit/UIKit.h>
#import <Parse/Parse.h>
#import "AsyncImageView.h"
#import "SearchViewController.h"
#interface MatchCenterViewController : UIViewController <UITableViewDataSource>
#property (nonatomic) IBOutlet UITextField *itemSearch;
#property (nonatomic, strong) NSArray *imageURLs;
#end
MatchCenterViewController.m:
#import "MatchCenterViewController.h"
#import <UIKit/UIKit.h>
#interface MatchCenterViewController () <UITableViewDataSource, UITableViewDelegate>
#property (weak, nonatomic) IBOutlet UITableView *matchCenter;
#property (strong, nonatomic) NSArray *itemsArray;
#end
#implementation MatchCenterViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
//perform search with criteria just submitted
[PFCloud callFunctionInBackground:#"eBayMatchCenterSearch"
withParameters:#{#"item": self.itemSearch.text,
#"minPrice": #"250",
#"maxPrice": #"400",
#"itemCondition": #"New",
// #"itemLocation": #"US",
}
block:^(NSString *result, NSError *error) {
if (!error) {
NSLog(#"The result is '%#'", result);
}
}];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
#end

Answer 1

itemSearch is an IBOutlet and therefore won't be instantiated until the view loads. Setting its text value in prepareForSegue means you're setting the text value of nil.
Create a NSString property in your destination controller and set that during the segue. Then copy it to itemSearch.text in viewDidLoad.