我用
https://github.com/ReactiveCocoa/ReactiveCocoa实现了我的第一个代码.
用于登录用户.行[subscriber sendNext：user];被叫两次,但我希望只有一次.并且根本没有调用地图(因此永远不会调用自动登录)
这是我的实施：
-(RACSignal *) login:(Nsstring *)email pwd:(Nsstring *)pwd
{
DDLogInfo(@"Login user %@",email);
RACSignal *login = [RACSignal createSignal:^ RACdisposable *(id<RACSubscriber> subscriber)
{
[PFUser logInWithUsernameInBackground:email password:pwd block:^(PFUser *user,NSError *error) {
if (error) {
[subscriber sendError:error];
} else {
[subscriber sendNext:user];
[subscriber sendCompleted];
}
}];
return nil;
}];
[login map:^(PFUser *user) {
return [self autoLogin:user];
}];
return login;
}
这样称呼：
Nsstring *email = data[@"email"];
Nsstring *pwd = data[@"pwd"];
[SVProgressHUD showWithMaskType:SVProgressHUDMaskTypeBlack];
RACSignal *login = [[SyncEngine server] login:email pwd:pwd];
[login
subscribeCompleted:^
{
[[NSNotificationCenter defaultCenter]
postNotificationName:NOTIFY_LOGIN_CHANGED
object:self];
[SVProgressHUD showSuccessWithStatus:LOC_OK];
[self cancelForm];
}];
[login
subscribeError:^(NSError *error)
{
[SVProgressHUD dismiss];
[AppUrls alertError:LOC_ERROR_LOGING msg:error.userInfo[@"error"]];
}];
解决方法
发生这种情况是因为每当对信号进行订阅时,传递给[RACSignal createSignal：]的块都会执行,并且您的代码会创建两个单独的订阅：
[login subscribeCompleted:^{ ... }];
[login subscribeError:^(NSError *error) { ... }];
如果您只想创建单个订阅,请使用方法 – [RACSignal subscribeError：completed：]：
[login subscribeError:^(NSError *error) {
[SVProgressHUD dismiss];
[AppUrls alertError:LOC_ERROR_LOGING msg:error.userInfo[@"error"]];
}
completed:^{
[[NSNotificationCenter defaultCenter]
postNotificationName:NOTIFY_LOGIN_CHANGED
object:self];
[SVProgressHUD showSuccessWithStatus:LOC_OK];
[self cancelForm];
}];