申请加入群组

[[OIMManager manager] joinGroup:groupID
    reqMsg:@"申请加入项目讨论组"
    joinSource:OIMJoinTypeSearch
    ex:nil
    onSuccess:^(NSString * _Nullable data) { [self showApplicationSubmitted]; }
    onFailure:^(NSInteger code, NSString *message) {
        [self showErrorCode:code message:message];
    }];