Question

我正在使用zxing库来扫描条形码。每当我扫描错误的条形码时，邮件编写者都会打开一封邮件，说明扫描了错误的条形码。当我们解雇邮件编辑器时，我们可以再次扫描。但是，当我解雇邮件编辑器时，我的应用程序崩溃说“[CALayer isKindOfClass：]：发送到解除分配的实例的消息”

int main(int argc, char * argv[])
{
  @autoreleasepool {
    return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));// app crashed at this line
}
}

这就是我所拥有的

-(void)viewDidDisappear:(BOOL)animated{

[super viewDidDisappear:animated];

 [self.capture.layer removeFromSuperlayer];

   [self.view.layer removeFromSuperlayer];
   self.view = nil;
    self.capture=nil;

}


- (void)viewWillAppear:(BOOL)animated {
  [super viewWillAppear:animated];

self.capture.delegate = self;
self.capture.layer.frame = self.view.bounds;
_scanRectView.layer.borderColor=[UIColor redColor].CGColor;
_scanRectView.layer.borderWidth = 2;


CGAffineTransform captureSizeTransform = CGAffineTransformMakeScale(320 / self.view.frame.size.width, 480 / self.view.frame.size.height);
self.capture.scanRect = CGRectApplyAffineTransform(self.scanRectView.frame, captureSizeTransform);
}


- (void)viewDidLoad
{
[super viewDidLoad];

//initialising the zxing library to start the camera
self.capture = [[ZXCapture alloc] init];
self.capture.camera = self.capture.back;


self.capture.focusMode = AVCaptureFocusModeContinuousAutoFocus;
self.capture.rotation = 90.0f;

self.capture.layer.frame = self.view.bounds;
[self.view.layer addSublayer:self.capture.layer];



[self.view bringSubviewToFront:self.scanRectView];
[self.view bringSubviewToFront:self.decodedLabel];


}

请告诉我，我在哪里做错了。

提前致谢。

Answer 1

我认为你的viewDidDisappear方法错误

它将是

   -(void)viewDidDisappear:(BOOL)animated{

    [super viewDidDisappear:animated];
    [self.capture.layer removeFromSuperlayer];
    self.capture=nil;
}


- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    //initialising the zxing library to start the camera
    self.capture = [[ZXCapture alloc] init];
    self.capture.camera = self.capture.back;


    self.capture.focusMode = AVCaptureFocusModeContinuousAutoFocus;
    self.capture.rotation = 90.0f;

    self.capture.layer.frame = self.view.bounds;
    [self.view.layer addSublayer:self.capture.layer];



    [self.view bringSubviewToFront:self.scanRectView];
    [self.view bringSubviewToFront:self.decodedLabel];


    self.capture.delegate = self;
    self.capture.layer.frame = self.view.bounds;
    _scanRectView.layer.borderColor=[UIColor redColor].CGColor;
    _scanRectView.layer.borderWidth = 2;


    CGAffineTransform captureSizeTransform = CGAffineTransformMakeScale(320 / self.view.frame.size.width, 480 / self.view.frame.size.height);
    self.capture.scanRect = CGRectApplyAffineTransform(self.scanRectView.frame, captureSizeTransform);
}


- (void)viewDidLoad
{
    [super viewDidLoad];
}

[CALayer isKindOfClass：]：发送到解除分配的实例的消息

1 个答案: