我的视图控制器中有两个UISegmentedControls，单击提交按钮后，我收到下面的错误。我相信无论是一个UISegmentedControls，或两个文本字段在我的故事板没有正确发送他们的数据。然而，我似乎无法弄清楚是什么导致了这一点。
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSPlaceholderDictionary initWithObjects:forKeys:count:]: attempt to insert nil object from objects[4]'
*** First throw call stack:
(
0 CoreFoundation 0x02a7a1e4 __exceptionPreprocess + 180
1 libobjc.A.dylib 0x026388e5 objc_exception_throw + 44
2 CoreFoundation 0x02a40376 -[__NSPlaceholderDictionary initWithObjects:forKeys:count:] + 390
3 CoreFoundation 0x02a6dc29 +[NSDictionary dictionaryWithObjects:forKeys:count:] + 73
4 Parse+Storyboard 0x000055db -[CriteriaViewController submitButton:] + 395
5 libobjc.A.dylib 0x0264a880 -[NSObject performSelector:withObject:withObject:] + 77
6 UIKit 0x012fa3b9 -[UIApplication sendAction:to:from:forEvent:] + 108
7 UIKit 0x012fa345 -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 61
8 UIKit 0x013fbbd1 -[UIControl sendAction:to:forEvent:] + 66
9 UIKit 0x013fbfc6 -[UIControl _sendActionsForEvents:withEvent:] + 577
10 UIKit 0x013fb243 -[UIControl touchesEnded:withEvent:] + 641
11 UIKit 0x01339ddd -[UIWindow _sendTouchesForEvent:] + 852
12 UIKit 0x0133a9d1 -[UIWindow sendEvent:] + 1117
13 UIKit 0x0130c5f2 -[UIApplication sendEvent:] + 242
14 UIKit 0x012f6353 _UIApplicationHandleEventQueue + 11455
15 CoreFoundation 0x02a0377f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
16 CoreFoundation 0x02a0310b __CFRunLoopDoSources0 + 235
17 CoreFoundation 0x02a201ae __CFRunLoopRun + 910
18 CoreFoundation 0x02a1f9d3 CFRunLoopRunSpecific + 467
19 CoreFoundation 0x02a1f7eb CFRunLoopRunInMode + 123
20 GraphicsServices 0x02cd75ee GSEventRunModal + 192
21 GraphicsServices 0x02cd742b GSEventRun + 104
22 UIKit 0x012f8f9b UIApplicationMain + 1225
23 Parse+Storyboard 0x000024ed main + 141
24 libdyld.dylib 0x038d4701 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)
CriteriaViewController.m:
#import "CriteriaViewController.h"
@interface CriteriaViewController ()
@property (weak, nonatomic) IBOutlet UISegmentedControl *itemConditionSegment;
@property (weak, nonatomic) IBOutlet UISegmentedControl *itemLocationSegment;
@end
@implementation CriteriaViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
UISegmentedControl *conditionSegmentedControl = [[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:@"Only New", @"Any", nil]];
conditionSegmentedControl.frame = CGRectMake(87, 190, 157, 30);
conditionSegmentedControl.selectedSegmentIndex = 0;
conditionSegmentedControl.tintColor = [UIColor blackColor];
[conditionSegmentedControl addTarget:self action:@selector(ConditionSegmentControlAction:) forControlEvents: UIControlEventValueChanged];
[self.view addSubview:conditionSegmentedControl];
UISegmentedControl *locationSegmentedControl = [[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:@"Fast Shipping", @"Large Selection", nil]];
locationSegmentedControl.frame = CGRectMake(67, 275, 200, 301);
locationSegmentedControl.selectedSegmentIndex = 0;
locationSegmentedControl.tintColor = [UIColor blackColor];
[locationSegmentedControl addTarget:self action:@selector(LocationSegmentControlAction:) forControlEvents: UIControlEventValueChanged];
[self.view addSubview:locationSegmentedControl];
// Submit button
UIButton *submitButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; // Create Round Rect Type button.
submitButton.frame = CGRectMake(100, 100, 100, 100); // define position and width and height for the button.
[submitButton setTitle:@"Submit" forState:UIControlStateNormal];
[submitButton addTarget:self action:@selector(submitButton:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:submitButton];
}
- (void)ConditionSegmentControlAction:(UISegmentedControl *)segment
{
if(segment.selectedSegmentIndex == 0)
{
// set condition to new
self.itemCondition = @"new";
}
else if (segment.selectedSegmentIndex == 1)
{
// set condition to all
self.itemCondition = @"all";
}
}
- (void)LocationSegmentControlAction:(UISegmentedControl *)segment
{
if(segment.selectedSegmentIndex == 0)
{
// set location to us
self.itemLocation = @"US";
}
else if (segment.selectedSegmentIndex == 1)
{
// set clocation to worldwide
self.itemLocation = @"Worldwide";
}
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
//add all the info to users respective new category object
- (IBAction)submitButton:(id)sender
{
//if (self.minPrice.text.length > 0 && self.maxPrice.text.length > 0) {
[PFCloud callFunctionInBackground:@"userCategorySave"
withParameters:@{@"categoryId": self.chosenCategory,
@"minPrice": self.minPrice,
@"maxPrice": self.maxPrice,
@"itemCondition": self.itemCondition,
@"itemLocation": self.itemLocation}
block:^(NSString *result, NSError *error) {
if (!error) {
NSLog(@"Criteria successfully saved.");
[self performSegueWithIdentifier:@"SearchCategoryChooserToMatchCenterSegue" sender:self];
}
}];
//}
}
- (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
@{@"categoryId": self.chosenCategory,
@"minPrice": self.minPrice,
@"maxPrice": self.maxPrice,
@"itemCondition": self.itemCondition,
@"itemLocation": self.itemLocation}
这是一个创建NSDictionary的文字构造。编译器将其转换为对initWithObjects:forKeys:count的调用。方法坚持要传递的所有对象都存在—否则将抛出您所看到的断言。您可以在调用堆栈中看到事件序列-
+[NSDictionary dictionaryWithObjects:forKeys:count:] + 73
-[CriteriaViewController submitButton:] + 395
submitButton被调用，在那里它试图创建一个字典，这崩溃了。
如果相关数据不存在，可以更改accessor方法以返回NSNull对象，或者确保您实际上有/lazy load所有这些值的数据