EXC_BAD_ACCESS 无法识别的选择器发送到实例

Question

//adds a button to scroll list  
-(void) addNode:(NSString *) atitle{  
     UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];  
     [btn setTitle:atitle forState:UIControlStateNormal];  
     [btn addTarget:self action:@selector(buttonTouched:)   forControlEvents:UIControlEventTouchUpInside]; // handle touch  
     [buttons addObject:btn];  
....
}

//a data button was pressed  
-(void) buttonTouched:(id)sender{  
   int index = [buttons indexOfObject:sender];  
   NSString *key = [sender titleLabel].text;  
}  

@interface MainViewController : UIViewController <FlipsideViewControllerDelegate>

-(id) init{  
    self = [super init];  
    ...  
}  

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.  
- (void)viewDidLoad {  
 [super viewDidLoad];  
 [[NSNotificationCenter defaultCenter] postNotificationName:@"ViewDidLoad" object:nil];  
}  

-(void) awakeFromNib{  
 [self loadData]; // loads some data  
  //calls addNode for a bunch of dynamic data
}  

---

出现此错误：

2010-07-29 10:19:45.428 DataManager[2945:207] -[NSCFString buttonTouched:]: unrecognized selector sent to instance 0x593abb0  
2010-07-29 10:19:45.429 DataManager[2945:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSCFString buttonTouched:]: unrecognized selector sent to instance 0x593abb0'  
*** Call stack at first throw:  
(  
 0   CoreFoundation                      0x02399919 __exceptionPreprocess + 185  
 1   libobjc.A.dylib                     0x024e75de objc_exception_throw + 47  
 2   CoreFoundation                      0x0239b42b -[NSObject(NSObject)   doesNotRecognizeSelector:] + 187  
 3   CoreFoundation                      0x0230b116 ___forwarding___ + 966  
 4   CoreFoundation                      0x0230acd2 _CF_forwarding_prep_0 + 50  
 5   UIKit                               0x002bde14 -[UIApplication  sendAction:to:from:forEvent:] + 119  
 6   UIKit                               0x003476c8 -[UIControl sendAction:to:forEvent:] + 67  
 7   UIKit                               0x00349b4a -[UIControl(Internal) _sendActionsForEvents:withEvent:] + 527  
 8   UIKit                               0x003486f7 -[UIControl touchesEnded:withEvent:] + 458  
 9   UIKit                               0x00535070 _UIGestureRecognizerUpdateObserver + 3687  
 10  CoreFoundation                      0x0237ad1b __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 27  
 11  CoreFoundation                      0x0230f987 __CFRunLoopDoObservers + 295  
 12  CoreFoundation                      0x022d8c17 __CFRunLoopRun + 1575  
 13  CoreFoundation                      0x022d8280 CFRunLoopRunSpecific + 208  
 14  CoreFoundation                      0x022d81a1 CFRunLoopRunInMode + 97  
 15  GraphicsServices                    0x02bfe2c8 GSEventRunModal + 217  
 16  GraphicsServices                    0x02bfe38d GSEventRun + 115  
 17  UIKit                               0x002cbb58 UIApplicationMain + 1160  
 18  DataManager                         0x00002940 main + 102  
 19  DataManager                         0x000028d1 start + 53  
)  
terminate called after throwing an instance of 'NSException'  
Program received signal:  “SIGABRT”.  
kill  
kill  

The Debugger has exited due to signal 15 (SIGTERM).The Debugger has exited due to signal 15 (SIGTERM). 

Answer 1

在将操作添加到按钮之前，我确实添加了 [self keep]; ，现在它可以工作了！

-(void) addNode:(NSString *) atitle{  
UIButton *btn = [UIButton   buttonWithType:UIButtonTypeRoundedRect];  
    [btn setTitle:atitle forState:UIControlStateNormal];  
    [self retain];  
    [btn addTarget:self action:@selector(buttonTouched:) forControlEvents:UIControlEventTouchUpInside]; // handle touch  

有什么理由吗？
self 是处理一切的 UIViewController （至少我是这么认为的）

Answer 2

如果您使用 ARC 编译并通过以下方式以编程方式设置选择器：

[_backButton addTarget:self action:@selector(btnPressed:) forControlEvents:UIControlEventTouchUpInside];

EXC_BAD_ACCESS 会发生在我身上，因为我创建了一个父视图，然后将子视图添加到另一个视图。子视图（带有按钮）有其父版本。一切看起来都很好，直到选择按钮然后崩溃。

选择器的任何异常很可能都是类发布问题。 Retain 不应该用作解决方法（当然，在 ARC 编译中，您不能使用保留）。应检查代码以查找将释放对象父对象的函数中可能存在的寡指针。

希望有帮助。

Answer 3

buttons 是您初始化的数组吗（我假设您使用的是仅适用于数组的 addObject）？您说它应该将其添加到滚动列表中（我猜您的意思是滚动视图），但是您给出的错误使得您看起来像是将其传递到字符串对象中。

要添加到滚动视图，您可以这样做：

[someScrollview addSubview:btn];

另外，我没有看到在将对象添加到滚动视图时设置对象框架的任何地方。这是在将其添加为子视图之前需要执行的操作。

对我来说效果很好（注意，你应该在某个地方初始化并释放可变数组，我只是很快就做到了）：

控制台输出= 2010-07-29 15：54：54.563 Torch [52222：207]是的嗨和0

代码我用过的：

NSMutableArray *buttons; // in your .h interface

@property (nonatomic, retain) NSMutableArray *buttons; // in your .h

@synthesize buttons; // in your .m

(...)

-(IBAction) pushMyButtons {  
buttons = [[NSMutableArray alloc] init];

UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];  
[btn setTitle:@"Hi" forState:UIControlStateNormal];  
[btn setFrame:CGRectMake(65, 300, 200, 23)];
[btn addTarget:self action:@selector(buttonTouched:)   forControlEvents:UIControlEventTouchUpInside]; // handle touch  
[buttons addObject:btn];
[self.view addSubview:btn];  
}

//a data button was pressed  
-(void) buttonTouched:(id)sender{  

int index = [buttons indexOfObject:sender];  
NSString *key = [sender titleLabel].text; 
NSLog(@"Yep %@ and %d", key, index);

}