NSNotificationCenter 在自定义 UIView 控制器错误后关闭并再次呈现 [英] NSNotificationCenter in custom UIView controller error after dismiss and present again

问题描述

我有一个带有一些视图和自定义 uiview 的视图控制器.由于自定义 uiview，当我用手指触摸屏幕时，我会画一条线.

I have a view controller with some views and a custom uiview. When I touch the screen with my finger I draw a line thanks to the custom uiview.

为此，我通过通知中心将 location.x 和 location.y 发送到我的自定义 uiview 就像这样

To do that I send location.x and location.y through Notification Center to my custom uiview like that

CGPoint location = [touch locationInView:self.view];
userInfo = [NSMutableDictionary dictionary];
[userInfo setObject:[NSNumber numberWithFloat:location.x] forKey:@"x"];
[userInfo setObject:[NSNumber numberWithFloat:location.y] forKey:@"y"];
[[NSNotificationCenter defaultCenter] postNotificationName:@"addLine" object:self userInfo:userInfo];

在我的自定义 uiview 中，我以这种方式接收所有内容:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(addLine:) name:@"addLine" object:nil];
NSDictionary* userInfo = notification.userInfo;
float x = [[userInfo objectForKey:@"x"] floatValue];
float y = [[userInfo objectForKey:@"y"] floatValue];
p = CGPointMake(x,y);

而且效果很好！！！但只是第一次！！！

问题是如果我关闭初始化自定义 uiview 的主视图控制器并返回(例如再次播放)，则会出现此错误

The problem is If I dismiss the main viewcontroller where my custom uiview is initialized and I come back (to play again for example) this error appears

[__NSCFType addLine:]: 无法识别的选择器发送到实例0x1454dec0* 由于未捕获的异常NSInvalidArgumentException"而终止应用程序，原因:-[__NSCFType addLine:]:无法识别的选择器发送到实例 0x1454dec0'

[__NSCFType addLine:]: unrecognized selector sent to instance 0x1454dec0 * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFType addLine:]: unrecognized selector sent to instance 0x1454dec0'

似乎观察者在解雇后不再工作......你能帮我吗?

It seems that the observer doesn't work again after a dismiss...can you help me?

谢谢

推荐答案

您可能忘记删除 dealloc 中的 oberver

You have probably forgot to remove the oberver in the dealloc

- (void)dealloc {

    [[NSNotificationCenter defaultCenter] removeObserver:self];

}

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