iPhone开发：收到通知时为nil userInfo
我在一个操作中发布这样的通知：
DownloadStatus * status = [[DownloadStatus alloc] init];
[status setMessage: @"Download started"];
[status setStarted];
[status setCompleteSize: [filesize intValue]];
[userInfo setValue:status forKey:@"state"];
[[NSNotificationCenter defaultCenter]
postNotificationName:[targetURL absoluteString]
object:nil userInfo:userInfo];
[status release];
NSDictionary * userInfo = [NSDictionary dictionaryWithObject:targetURL
forKey:@"state"];
[[NSNotificationCenter defaultCenter]
addObserver:self selector:@selector(downloadStatusUpdate:)
name:videoUrl
object:nil];
- (void) downloadStatusUpdate:(NSNotification*) note {
NSDictionary * ui = note.userInfo; // Tried also [note userInfo]
if ( ui == nil ) {
DLog(@"Received an update message without userInfo!");
return;
}
DownloadStatus * state = [[ui allValues] objectAtIndex:0];
if ( state == nil ) {
DLog(@"Received notification without state!");
return;
}
DLog(@"Status message: %@", state.message);
[state release], state = nil;
[ui release], ui = nil; }
没有找到相关结果
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1 个回复
疮痪徘弦漏
NSDictionary * userInfo = [NSDictionary dictionaryWithObject:targetURL forKey:@"state"];要将本地分配给成员，同时保留它，那么您的代码应该在此行生成异常：因为它试图改变不可变对象。因此，更有可能的是，userInfo的值不会被存储，并且您在此时的消息传递为零。 所以，我认为 - 假设你将userInfo声明为'retain'类型属性，你想要替换：NSDictionary * userInfo = [NSDictionary dictionaryWithObject:targetURL forKey:@"state"];self.userInfo = [NSMutableDictionary dictionaryWithObject:targetURL forKey:@"state"];