KVO机制抛出错误？

我实现了一个照片编辑应用程序，其中我有一个摄像头拍摄的图像，一个是输出图像，我是在拍摄图像旁边显示的。每当我改变我捕捉的图像缩放或旋转，然后我想通知这个更改outputImage。对于这个塞纳里奥我写下面的代码，KVO机制抛出错误？

-(void)imageCapturedByCameraAPI:(UIImage *)theCapturedImage{ 
[[arOverlayVC view] removeFromSuperview]; 
capturedImageView.image = theCapturedImage; 
[self.view addSubview:imageEditorView]; 

rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotatePiece:)]; 
[capturedImageView addGestureRecognizer:rotationGesture]; 
**//KVO added for rotation** 
[capturedImageView addObserver:self forKeyPath:@"transform.rotate" options:NSKeyValueObservingOptionNew context:NULL]; 

pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scalePiece:)]; 
[pinchGesture setDelegate:self]; 
[capturedImageView addGestureRecognizer:pinchGesture]; 
**//KVO added for scaling** 
[capturedImageView addObserver:self forKeyPath:@"transform.scale" options:NSKeyValueObservingOptionNew context:NULL]; 

} 

    - (void)rotatePiece:(UIRotationGestureRecognizer *)gestureRecognizer { 
[self adjustAnchorPointForGestureRecognizer:gestureRecognizer]; 

if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) { 
    [gestureRecognizer view].transform = CGAffineTransformRotate([[gestureRecognizer view] transform], [gestureRecognizer rotation]); 
    [self editedImage]; 
    [gestureRecognizer setRotation:0]; 
} 
} 

- (void)scalePiece:(UIPinchGestureRecognizer *)gestureRecognizer { 
if([gestureRecognizer state] == UIGestureRecognizerStateBegan) { 
    lastScale = [gestureRecognizer scale]; 
} 

if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || 
    [gestureRecognizer state] == UIGestureRecognizerStateChanged) { 

    CGFloat currentScale = [[[gestureRecognizer view].layer valueForKeyPath:@"transform.scale"] floatValue]; 

    const CGFloat kMaxScale = 2.0; 
    const CGFloat kMinScale = 1.0; 

    CGFloat newScale = 1 - (lastScale - [gestureRecognizer scale]); 
    newScale = MIN(newScale, kMaxScale/currentScale); 
    newScale = MAX(newScale, kMinScale/currentScale); 
    CGAffineTransform transform = CGAffineTransformScale([[gestureRecognizer view] transform], newScale, newScale); 
    [gestureRecognizer view].transform = transform; 
    lastScale = [gestureRecognizer scale]; 
} 
} 

    - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer { 
// if the gesture recognizers are on different views, don't allow simultaneous recognition 

if (gestureRecognizer.view != otherGestureRecognizer.view) 
    return NO; 

// if either of the gesture recognizers is the long press, don't allow simultaneous recognition 
if ([gestureRecognizer isKindOfClass:[UILongPressGestureRecognizer class]] || [otherGestureRecognizer isKindOfClass:[UILongPressGestureRecognizer class]]) 
    return NO; 

return YES; 
    } 

- (void)adjustAnchorPointForGestureRecognizer:(UIGestureRecognizer *)gestureRecognizer { 
if (gestureRecognizer.state == UIGestureRecognizerStateBegan) { 
    UIView *piece = gestureRecognizer.view; 
    CGPoint locationInView = [gestureRecognizer locationInView:piece]; 
    CGPoint locationInSuperview = [gestureRecognizer locationInView:piece.superview]; 

    piece.layer.anchorPoint = CGPointMake(locationInView.x/piece.bounds.size.width, locationInView.y/piece.bounds.size.height); 
    piece.center = locationInSuperview; 
} 
    }

现在我的观察方法是，

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context 
    { 
if(object == capturedImageView && ([keyPath isEqualToString:@"transform.rotate"] || [keyPath isEqualToString:@"transform.scale"])) { 
    NSLog(@"KVO detected"); 
    } 
    }

我发现了以下错误，

一个实例类NSConcreteValue的0x189f40被同时键释放价值观察员仍然登记在案。观察信息被泄露，甚至可能被错误地附加到其他一些对象。在NSKVODeallocateBreak上设置一个断点，在调试器中停止。下面是当前观测信息：（背景：为0x0，物业：0x189ff0>

一个实例类NSConcreteValue的0x188cb0被释放，而键值观察家仍用它注册的观测信息被泄露，甚至可能误成了。连接到其他一些对象设置上NSKVODeallocateBreak断点停在这里的调试下面是当前观测信息：。（背景：为0x0，物业：0x188d80>

*终止应用程序由于未捕获的异常 “N SInternalInconsistencyException'，原因：'无法更新关键路径 “transform.scale”的观察者，很可能是因为密钥“变换”的值已更改，而没有发送适当的KVO 通知。检查UIImageView 类的KVO合规性。'

来源

2013-02-26 Tirth

有更多的问题与您的代码，例如不检查上下文。在这个答案中，我已经编译了如何获得KVO的一些经验法则：http://stackoverflow.com/questions/9231896/kvo-how-to-check-if-an-object-is-an-observer – 2013-02-26 09:30:33

的错误消息说

类的一个实例被释放，而键值观察家仍用它

你需要capturedImageView之前删除的观察注册使用removeObserver:forKeyPath:context:被释放

确保您具有注册/取消注册的计数或不打破KVO。你想知道更多关于志愿

我，这个环节是有帮助的：http://www.mikeash.com/pyblog/key-value-observing-done-right.html

和第2部分：http://www.mikeash.com/pyblog/friday-qa-2012-03-02-key-value-observing-done-right-take-2.html

来源

2013-02-26 09:26:01

你的意思是我想创建UIImageview的capturedImageView的子类，在那里我想实现delloc方法并删除我的观察键。不要使用ARC如此delloc方法工作在ARC的UIImageview的子类？ – Tirth 2013-02-26 09:51:58

弧只处理内存NSObject的&有限公司，其他一切（例如韩国国际志愿者组织或网络连接或文件写入），你需要手动清理

覆盖 - 观测的变化时（无效）的dealloc为

- (void)dealloc { 
    [capturedImageView removeObserver:self forKeyPath:@"transform.scale"]; 
}

来源

2013-02-26 09:32:36

你的意思是我想创建UIImageView的capturedImageView的子类，在那里我想实现delloc方法并删除我的观察键。不要使用ARC如此delloc方法工作在ARC的UIImageview的子类？ – Tirth 2013-02-26 09:52:21

没有ADDS观察者的类，将其删除。所以在你的VC的dealloc方法中，你用captureImageView完成了，你移除了观察者 – 2013-02-26 10:18:54

KVO机制抛出错误？

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