更改 View 时 iOS 应用程序崩溃

Question

我正在构建一个有很多 View 的应用程序。有一次，按下按钮后， View 从一个 View 变回初始 View Controller 。初始 View Controller 只有在创建新类时添加的默认代码，它唯一的用途是保存用于切换到其他 View 的按钮。带有按钮的 View 有一个文本字段、一个“退出”按钮和几个标签。如果我在 未触及 textField 的情况下按下“退出”按钮，一切顺利，我将返回到原始 View Controller ，在那里我可以继续。但是，如果我决定在 textField 上编辑(甚至只是打开键盘)，然后按下退出按钮，应用程序就会崩溃，出现 sigabrt 错误。这是我得到的错误代码。

2016-01-28 17:16:59.666 AutoTutor[64646:2461958] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[ATPractice answerBox:]: unrecognized selector sent to instance 0x7fb58855d1e0'
*** First throw call stack:
(
0   CoreFoundation                      0x0000000104579e65 __exceptionPreprocess + 165
1   libobjc.A.dylib                     0x0000000103ff2deb objc_exception_throw + 48
2   CoreFoundation                      0x000000010458248d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3   CoreFoundation                      0x00000001044cf90a ___forwarding___ + 970
4   CoreFoundation                      0x00000001044cf4b8 _CF_forwarding_prep_0 + 120
5   UIKit                               0x0000000104928194 -[UIApplication sendAction:to:from:forEvent:] + 92
6   UIKit                               0x0000000104a976fc -[UIControl sendAction:to:forEvent:] + 67
7   UIKit                               0x0000000104a979c8 -[UIControl _sendActionsForEvents:withEvent:] + 311
8   UIKit                               0x00000001052ff506 -[UITextField _resignFirstResponder] + 298
9   UIKit                               0x0000000104b346ea -[UIResponder _finishResignFirstResponder] + 292
10  UIKit                               0x00000001052ff330 -[UITextField _finishResignFirstResponder] + 49
11  UIKit                               0x0000000104b34799 -[UIResponder resignFirstResponder] + 140
12  UIKit                               0x00000001052ff1fd -[UITextField resignFirstResponder] + 136
13  UIKit                               0x00000001049c9605 -[UIView(Hierarchy) _removeFirstResponderFromSubtree] + 161
14  UIKit                               0x00000001049c9b32 __UIViewWillBeRemovedFromSuperview + 71
15  UIKit                               0x00000001049c9950 -[UIView(Hierarchy) removeFromSuperview] + 99
16  UIKit                               0x0000000104a93493 __71-[UIPresentationController _initViewHierarchyForPresentationSuperview:]_block_invoke596 + 739
17  UIKit                               0x0000000104a8d756 -[UIPresentationController transitionDidFinish:] + 111
18  UIKit                               0x0000000104c62e0b -[_UICurrentContextPresentationController transitionDidFinish:] + 42
19  UIKit                               0x0000000104a91159 __56-[UIPresentationController runTransitionForCurrentState]_block_invoke_2 + 183
20  UIKit                               0x000000010532cd20 -[_UIViewControllerTransitionContext completeTransition:] + 101
21  UIKit                               0x0000000104a8a90f -[UITransitionView notifyDidCompleteTransition:] + 252
22  UIKit                               0x0000000104a8a620 -[UITransitionView _didCompleteTransition:] + 1344
23  UIKit                               0x0000000104a8cd8c -[UITransitionView _transitionDidStop:finished:] + 104
24  UIKit                               0x00000001049b02af -[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 241
25  UIKit                               0x00000001049b065e -[UIViewAnimationState animationDidStop:finished:] + 80
26  QuartzCore                          0x0000000107370fa0 _ZN2CA5Layer23run_animation_callbacksEPv + 308
27  libdispatch.dylib                   0x0000000107f8e49b _dispatch_client_callout + 8
28  libdispatch.dylib                   0x0000000107f762af _dispatch_main_queue_callback_4CF + 1738
29  CoreFoundation                      0x00000001044d9d09 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
30  CoreFoundation                      0x000000010449b2c9 __CFRunLoopRun + 2073
31  CoreFoundation                      0x000000010449a828 CFRunLoopRunSpecific + 488
32  GraphicsServices                    0x0000000107a2aad2 GSEventRunModal + 161
33  UIKit                               0x0000000104926610 UIApplicationMain + 171
34  AutoTutor                           0x000000010379a8ef main + 111
35  libdyld.dylib                       0x0000000107fc292d start + 1
36  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb) 

ATPractice 是用于带有文本字段的 View Controller 的类的名称，answerBox 是文本字段的名称。任何帮助将不胜感激。

初始viewController的.m文件:

#import "ViewController.h"



@interface ViewController ()

@end

@implementation ViewController


- (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

里面没有任何内容，这是默认内容。

初始viewController的.h文件:

#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>

@interface ViewController : UIViewController
{

}

@end

同样，默认内容。

使用退出按钮的 .m 文件查看 Controller

#import "ATPractice.h"
#import "DDMathParser.h"
#import <AVFoundation/AVFoundation.h>

@interface ATPractice ()

@end

@implementation ATPractice

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
}

- (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

带有一些额外导入的默认内容。

使用退出按钮的 .h 文件查看 Controller

#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#import <AVFoundation/AVFoundation.h>

@interface ATPractice : UIViewController <UITextFieldDelegate>
{
IBOutlet UILabel *instructionsLabel;
IBOutlet UILabel *questionLabel;
IBOutlet UILabel *percentageLabel;
IBOutlet UILabel *levelLabel;

IBOutlet UIImageView *imageView;
IBOutlet UITextField *answerBox;

IBOutlet UIScrollView *zoomView;

NSInteger questionInt;
NSInteger levelInt;
}
@end

只是一些 IBOutlets 和 NSIntegers。

Answer 1

检查您的 Nib / Storyboard，确保没有任何杂散连接。看起来您的 UITextField 上可能有一个用于其操作之一的操作。