IOS设置别名不成功

[JPUSHService setAlias:userId callbackSelector:nil object:nil];
直接使用此方法设置推送不成功。

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[[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(networkDidLogin:)
                                                 name:kJPFNetworkDidLoginNotification
                                               object:nil];

- (void)networkDidLogin:(NSNotification *)notification {
    NSString *userId = [[NSUserDefaults standardUserDefaults] objectForKey:kLastUserKey];
    [JPUSHService setAlias:userId callbackSelector:nil object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:kJPFNetworkDidLoginNotification
                                                  object:nil];
}

使用此方法设置，登录成功后又不执行networkDidLogin: 方法，别名绑定不成功，求解！