diff --git a/fastNLP/core/callbacks/more_evaluate_callback.py b/fastNLP/core/callbacks/more_evaluate_callback.py
index 538ffc10..e11bacde 100644
--- a/fastNLP/core/callbacks/more_evaluate_callback.py
+++ b/fastNLP/core/callbacks/more_evaluate_callback.py
@@ -85,7 +85,8 @@ class MoreEvaluateCallback(HasMonitorCallback):
         if watch_monitor is None and evaluate_every is None:
             raise RuntimeError("`evaluate_every` and `watch_monitor` cannot be None at the same time.")
         if watch_monitor is not None and evaluate_every is not None:
-            raise RuntimeError("`evaluate_every` and `watch_monitor` cannot be set at the same time.")
+            raise RuntimeError(f"`evaluate_every`({evaluate_every}) and `watch_monitor`({watch_monitor}) "
+                               f"cannot be set at the same time.")
 
         if topk_monitor is not None and topk == 0:
             raise RuntimeError("`topk_monitor` is set, but `topk` is 0.")
diff --git a/fastNLP/core/callbacks/topk_saver.py b/fastNLP/core/callbacks/topk_saver.py
index 32341e7b..0317b7e2 100644
--- a/fastNLP/core/callbacks/topk_saver.py
+++ b/fastNLP/core/callbacks/topk_saver.py
@@ -36,7 +36,8 @@ class Saver:
                  model_save_fn:Callable=None, **kwargs):
         if folder is None:
             folder = Path.cwd().absolute()
-            logger.info(f"Parameter `folder` is None, and fastNLP will use {folder} to save and load your model.")
+            if save_object is not None:
+                logger.info(f"Parameter `folder` is None, and fastNLP will use {folder} to save and load your model.")
         folder = Path(folder)
         if not folder.exists():
             folder.mkdir(parents=True, exist_ok=True)
@@ -208,7 +209,7 @@ class TopkSaver(ResultsMonitor, Saver):
         if topk is None:
             topk = 0
         ResultsMonitor.__init__(self, monitor, larger_better)
-        Saver.__init__(self, folder, save_object, only_state_dict, model_save_fn, **kwargs)
+        Saver.__init__(self, folder, save_object if topk!=0 else None, only_state_dict, model_save_fn, **kwargs)
 
         if monitor is not None and topk == 0:
             raise RuntimeError("`monitor` is set, but `topk` is 0.")
diff --git a/fastNLP/core/samplers/reproducible_batch_sampler.py b/fastNLP/core/samplers/reproducible_batch_sampler.py
index 9c7bf2c6..679bb1cf 100644
--- a/fastNLP/core/samplers/reproducible_batch_sampler.py
+++ b/fastNLP/core/samplers/reproducible_batch_sampler.py
@@ -210,7 +210,7 @@ class RandomBatchSampler(ReproducibleBatchSampler):
             self.num_consumed_samples = 0
         self.during_iter = True
 
-        indices = list(range(len(self.dataset)))
+        indices = list(range(getattr(self.dataset, 'total_len', len(self.dataset))))
 
         if self.shuffle:
             if self.num_consumed_samples > 0:  # 需要先按照原来的排序，删掉多余的
@@ -237,7 +237,7 @@ class RandomBatchSampler(ReproducibleBatchSampler):
                 if len(indices)%self.batch_size!=0:
                     batches.append(indices[_num_batches*self.batch_size:])
 
-        need_pad_num = (len(self.dataset)-self.num_consumed_samples) % self.num_replicas
+        need_pad_num = (getattr(self.dataset, 'total_len', len(self.dataset))-self.num_consumed_samples) % self.num_replicas
         if self.pad and need_pad_num !=0 and need_pad_num<=self.rank:
             if len(batches) > 0:
                 if len(batches[-1])<self.batch_size:
@@ -290,9 +290,9 @@ class RandomBatchSampler(ReproducibleBatchSampler):
     @property
     def batch_idx_in_epoch(self):
         if self.drop_last:
-            return len(self.dataset) // self.num_replicas // self.batch_size - self.num_left_samples // self.batch_size
+            return getattr(self.dataset, 'total_len', len(self.dataset)) // self.num_replicas // self.batch_size - self.num_left_samples // self.batch_size
         else:
-            return (len(self.dataset) // self.num_replicas + self.batch_size - 1) // self.batch_size - \
+            return (getattr(self.dataset, 'total_len', len(self.dataset)) // self.num_replicas + self.batch_size - 1) // self.batch_size - \
                    (self.num_left_samples + self.batch_size - 1) // self.batch_size
 
     @property
@@ -313,8 +313,8 @@ class RandomBatchSampler(ReproducibleBatchSampler):
         :return:
         """
         num_consumed_samples = self.num_consumed_samples
-        return math.ceil((len(self.dataset) - num_consumed_samples) / self.num_replicas) if \
-            self.pad else math.floor(((len(self.dataset) - num_consumed_samples) / self.num_replicas))
+        return math.ceil((getattr(self.dataset, 'total_len', len(self.dataset)) - num_consumed_samples) / self.num_replicas) if \
+            self.pad else math.floor(((getattr(self.dataset, 'total_len', len(self.dataset)) - num_consumed_samples) / self.num_replicas))
 
     def __len__(self)->int:
         """
@@ -332,7 +332,7 @@ class RandomBatchSampler(ReproducibleBatchSampler):
             raise RuntimeError("BucketedBatchSampler does not support saving before last checkpoint states have been"
                                " consumed. ")
         states = {'seed': self.seed, 'epoch': self.epoch, 'num_consumed_samples': self.num_consumed_samples,
-                  'sampler_type': self.__class__.__name__, 'length': len(self.dataset), 'shuffle': self.shuffle,
+                  'sampler_type': self.__class__.__name__, 'length': getattr(self.dataset, 'total_len', len(self.dataset)), 'shuffle': self.shuffle,
                   'batch_size': self.batch_size,
                   'num_replicas': self.num_replicas}
 
@@ -347,7 +347,7 @@ class RandomBatchSampler(ReproducibleBatchSampler):
                                                                   f"we cannot use {self.__class__.__name__} to load it."
 
         length = states['length']
-        assert length == len(self.dataset), "The number of samples is different between the checkpoint record " \
+        assert length == getattr(self.dataset, 'total_len', len(self.dataset)), "The number of samples is different between the checkpoint record " \
                                             "and current dataset."
         self.seed = states['seed']
         self.epoch = states['epoch']
@@ -464,8 +464,8 @@ class BucketedBatchSampler(ReproducibleBatchSampler):
         :return:
         """
         num_consumed_samples = self.num_consumed_samples
-        return math.ceil((len(self.dataset) - num_consumed_samples) / self.num_replicas) if \
-            self.pad else math.floor(((len(self.dataset) - num_consumed_samples) / self.num_replicas))
+        return math.ceil((getattr(self.dataset, 'total_len', len(self.dataset)) - num_consumed_samples) / self.num_replicas) if \
+            self.pad else math.floor(((getattr(self.dataset, 'total_len', len(self.dataset)) - num_consumed_samples) / self.num_replicas))
 
     def __len__(self)->int:
         """
@@ -515,7 +515,7 @@ class BucketedBatchSampler(ReproducibleBatchSampler):
                 if len(sorted_indices)%self.batch_size!=0:
                     batches.append(sorted_indices[_num_batches*self.batch_size:])
 
-        need_pad_num = (len(self.dataset)-self.num_consumed_samples) % self.num_replicas
+        need_pad_num = (getattr(self.dataset, 'total_len', len(self.dataset))-self.num_consumed_samples) % self.num_replicas
         if self.pad and need_pad_num !=0 and need_pad_num<=self.rank:
             if len(batches) > 0:
                 if len(batches[-1])<self.batch_size:
@@ -593,7 +593,7 @@ class BucketedBatchSampler(ReproducibleBatchSampler):
             raise RuntimeError("BucketedBatchSampler does not support saving before last checkpoint states have been"
                                " consumed. ")
         states = {'seed': self.seed, 'epoch': self.epoch, 'num_consumed_samples': self.num_consumed_samples,
-                  'sampler_type': self.__class__.__name__, 'length': len(self.dataset), 'shuffle': self.shuffle,
+                  'sampler_type': self.__class__.__name__, 'length': getattr(self.dataset, 'total_len', len(self.dataset)), 'shuffle': self.shuffle,
                   'batch_size': self.batch_size, 'num_batch_per_bucket': self.num_batch_per_bucket,
                   'num_replicas': self.num_replicas
                   }
@@ -609,7 +609,7 @@ class BucketedBatchSampler(ReproducibleBatchSampler):
                                                                   f"we cannot use {self.__class__.__name__} to load it."
 
         length = states['length']
-        assert length == len(self.dataset), "The number of samples is different between the checkpoint record " \
+        assert length == getattr(self.dataset, 'total_len', len(self.dataset)), "The number of samples is different between the checkpoint record " \
                                             "and current dataset."
         self.seed = states['seed']
         self.epoch = states['epoch']
@@ -630,7 +630,7 @@ class BucketedBatchSampler(ReproducibleBatchSampler):
     @property
     def batch_idx_in_epoch(self):
         if self.drop_last:
-            return len(self.dataset) // self.num_replicas // self.batch_size - self.num_left_samples // self.batch_size
+            return getattr(self.dataset, 'total_len', len(self.dataset)) // self.num_replicas // self.batch_size - self.num_left_samples // self.batch_size
         else:
-            return (len(self.dataset) // self.num_replicas + self.batch_size - 1) // self.batch_size - \
+            return (getattr(self.dataset, 'total_len', len(self.dataset)) // self.num_replicas + self.batch_size - 1) // self.batch_size - \
                    (self.num_left_samples + self.batch_size - 1) // self.batch_size
\ No newline at end of file
diff --git a/fastNLP/core/samplers/reproducible_sampler.py b/fastNLP/core/samplers/reproducible_sampler.py
index c7c8ad24..410daa3a 100644
--- a/fastNLP/core/samplers/reproducible_sampler.py
+++ b/fastNLP/core/samplers/reproducible_sampler.py
@@ -131,14 +131,14 @@ class RandomSampler(ReproducibleSampler):
         :return:
         """
         if self.shuffle:
-            indices = list(range(len(self.dataset)))
+            indices = list(range(getattr(self.dataset, 'total_len', len(self.dataset))))
             seed = self.seed + self.epoch
             rng = np.random.default_rng(abs(seed))
             rng.shuffle(indices)
             if self.epoch < 0:  # 防止用户忘记调用 set_epoch，至少这样可以保证每次epoch出来的index顺序不同。
                 self.epoch -= 1
         else:
-            indices = list(range(len(self.dataset)))
+            indices = list(range(getattr(self.dataset, 'total_len', len(self.dataset))))
         return indices
 
     def state_dict(self) -> Dict:
@@ -155,8 +155,8 @@ class RandomSampler(ReproducibleSampler):
                                                                   f"we cannot use {self.__class__.__name__} to load it."
 
         length = states['length']
-        assert length == len(self.dataset), f"The number of samples is different between the checkpoint record({length}) " \
-                                            f"and current dataset({len(self.dataset)})."
+        assert length == getattr(self.dataset, 'total_len', len(self.dataset)), f"The number of samples is different between the checkpoint record({length}) " \
+                                            f"and current dataset({getattr(self.dataset, 'total_len', len(self.dataset))})."
         self.seed = states['seed']
         self.epoch = states['epoch']
         self.num_consumed_samples = states['num_consumed_samples']
@@ -208,8 +208,8 @@ class RandomSampler(ReproducibleSampler):
         :return:
         """
         num_consumed_samples = self.num_consumed_samples
-        return math.ceil((len(self.dataset) - num_consumed_samples) / self.num_replicas) if \
-            self.pad else math.floor(((len(self.dataset) - num_consumed_samples) / self.num_replicas))
+        return math.ceil((getattr(self.dataset, 'total_len', len(self.dataset)) - num_consumed_samples) / self.num_replicas) if \
+            self.pad else math.floor(((getattr(self.dataset, 'total_len', len(self.dataset)) - num_consumed_samples) / self.num_replicas))
 
 
 class SequentialSampler(RandomSampler):
@@ -258,11 +258,11 @@ class SequentialSampler(RandomSampler):
 
         :return:
         """
-        return list(range(len(self.dataset)))
+        return list(range(getattr(self.dataset, 'total_len', len(self.dataset))))
 
     def state_dict(self) -> Dict:
         states = {'num_consumed_samples': self.num_consumed_samples, 'sampler_type': self.__class__.__name__,
-                  'length': len(self.dataset)
+                  'length': getattr(self.dataset, 'total_len', len(self.dataset))
                   }
         return states
 
@@ -275,8 +275,8 @@ class SequentialSampler(RandomSampler):
                                                                   f"we cannot use {self.__class__.__name__} to load it."
 
         length = states['length']
-        assert length == len(self.dataset), f"The number of samples is different between the checkpoint record({length}) " \
-                                            f"and current dataset({len(self.dataset)})."
+        assert length == getattr(self.dataset, 'total_len', len(self.dataset)), f"The number of samples is different between the checkpoint record({length}) " \
+                                            f"and current dataset({getattr(self.dataset, 'total_len', len(self.dataset))})."
         self.num_consumed_samples = states['num_consumed_samples']
         if self.num_consumed_samples >= length:  # 如果保存的时候已经到达了最后一个sample了，则直接将结果重置为0
             self.num_consumed_samples = 0
@@ -314,9 +314,9 @@ class SortedSampler(SequentialSampler):
             except BaseException as e:
                 logger.error(f"Cannot use {self.__class__.__name__} as length, since it is not sortable.")
 
-        assert len(length) == len(dataset), f"The length of `dataset`({len(dataset)}) and " \
-                                            f"`length`({len(length)}) should be equal."
-        assert len(self.sorted_indices) == len(dataset), "The indices and dataset should have equal length."
+        assert len(length) == getattr(self.dataset, 'total_len', len(self.dataset)), f"The length of `dataset`({len(dataset)}) and " \
+                                            f"`length`({getattr(self.dataset, 'total_len', len(self.dataset))}) should be equal."
+        assert len(self.sorted_indices) == getattr(self.dataset, 'total_len', len(self.dataset)), "The indices and dataset should have equal length."
 
         self.length = np.array(length, dtype=int)  # 按照长到短排列的序号。
         self.sorted_indices = np.argsort(self.length)[::-1].tolist()  # 按长度从高到低排序的
diff --git a/fastNLP/core/samplers/unrepeated_sampler.py b/fastNLP/core/samplers/unrepeated_sampler.py
index b76f9ffd..0ff55674 100644
--- a/fastNLP/core/samplers/unrepeated_sampler.py
+++ b/fastNLP/core/samplers/unrepeated_sampler.py
@@ -42,8 +42,8 @@ class UnrepeatedRandomSampler(UnrepeatedSampler):
         返回 sampler 一次完整的迭代过程会产生多少个index。多卡的情况下，只考虑当前rank；
         :return:
         """
-        num_common = len(self.dataset)//self.num_replicas
-        num_samples = num_common + int(self.rank < (len(self.dataset)-num_common*self.num_replicas))
+        num_common = getattr(self.dataset, 'total_len', len(self.dataset))//self.num_replicas
+        num_samples = num_common + int(self.rank < (getattr(self.dataset, 'total_len', len(self.dataset))-num_common*self.num_replicas))
         return num_samples
 
     def __iter__(self):
@@ -63,14 +63,14 @@ class UnrepeatedRandomSampler(UnrepeatedSampler):
         :return:
         """
         if self.shuffle:
-            indices = list(range(len(self.dataset)))
+            indices = list(range(getattr(self.dataset, 'total_len', len(self.dataset))))
             seed = self.seed + self.epoch
             rng = np.random.default_rng(abs(seed))
             rng.shuffle(indices)
             if self.epoch < 0:  # 防止用户忘记调用 set_epoch，至少这样可以保证每次epoch出来的index顺序不同。
                 self.epoch -= 1
         else:
-            indices = list(range(len(self.dataset)))
+            indices = list(range(getattr(self.dataset, 'total_len', len(self.dataset))))
         return indices
 
     def set_epoch(self, epoch: int) -> None:
@@ -84,8 +84,8 @@ class UnrepeatedRandomSampler(UnrepeatedSampler):
         :param rank:
         :return:
         """
-        assert num_replicas<=len(self.dataset), f"The number of replicas({num_replicas}) should be lesser than the " \
-                                                f"number of samples({len(self.dataset)})."
+        assert num_replicas<=getattr(self.dataset, 'total_len', len(self.dataset)), f"The number of replicas({num_replicas}) should be lesser than the " \
+                                                f"number of samples({getattr(self.dataset, 'total_len', len(self.dataset))})."
         assert num_replicas>0 and isinstance(num_replicas, int)
         assert isinstance(rank, int) and 0<=rank<num_replicas
         # 注意初始化该函数时，所有的状态都应当默认是一个 epoch 刚开始训练的状态；
@@ -147,5 +147,5 @@ class UnrepeatedSequentialSampler(UnrepeatedRandomSampler):
             yield index
 
     def generate_indices(self) -> List[int]:
-        return list(range(len(self.dataset)))
+        return list(range(getattr(self.dataset, 'total_len', len(self.dataset))))
 
diff --git a/fastNLP/core/utils/rich_progress.py b/fastNLP/core/utils/rich_progress.py
index 0e6d5a01..d8e9d45b 100644
--- a/fastNLP/core/utils/rich_progress.py
+++ b/fastNLP/core/utils/rich_progress.py
@@ -149,9 +149,12 @@ class FRichProgress(Progress, metaclass=Singleton):
             super().stop_task(task_id)
             super().remove_task(task_id)
             self.refresh()  # 使得bar不残留
-        # 这里需要注释掉的原因是由于，在dataset多次apply的过程中会出现自动换行的问题。以前保留这个的原因应该是由于evaluate结束bar不消失。
-        # if len(self._tasks) == 0:
-        #     self.live.stop()
+        if len(self._tasks) == 0:
+            # 这里将这个line函数给hack一下防止stop的时候打印出空行
+            old_line = getattr(self.live.console, 'line')
+            setattr(self.live.console, 'line', lambda *args,**kwargs:...)
+            self.live.stop()
+            setattr(self.live.console, 'line', old_line)
 
     def start(self) -> None:
         super().start()