iphone通知导致“无法识别的选择器发送到实例...” [英] iphone notification results in "unrecognized selector sent to instance..."

问题描述

为了简短起见，我在 ClassA 中注册以下 NSNotification 监听器（在<$ c $中） c> viewDidLoad ）：

To make it short, I'm registering the following NSNotification listener in ClassA (in viewDidLoad):

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playSong) name:@"playNotification" object:nil];

我在 ClassA.h中声明了选择器：

- (void)playSong:(NSNotification *) notification;

实施如下：

- (void)playSong:(NSNotification *) notification {
    NSString *theTitle = [notification object]; 
    NSLog(@"Play stuff", theTitle);
}

在 ClassB （在 tableView：didSelectRowAtIndexPath：方法）我有：

NSInteger row = [indexPath row];
NSString *stuff = [playlistArray objectAtIndex:row];
[[NSNotificationCenter defaultCenter] postNotificationName:@"playNotification" object:stuff];

这一切都会收到一条错误消息：

It all end up with an error message saying:

无法识别的选择器发送到实例

"unrecognized selector sent to instance"

playSong之前方法被调用。

有人可以帮帮我吗？从一个控制器向另一个控制器发布通知时我忘记了什么？

Can anybody please help me out here? What am I forgetting when posting a notification from one controller to another?

推荐答案

您的 @selector 需要一个：字符，如果它是一个参数：

Your @selector needs a : character if it is to take an argument:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playSong:) name:@"playNotification" object:nil];

ClassA的实例不执行 回复 playSong 选择器，但他们做回应 playSong：选择器。

Instances of ClassA do not respond to the playSong selector, but they do respond to the playSong: selector.

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