您好，请教两个小问题。

一个是断开连接，liteBluetooth.closeBluetoothGatt();不知道调用的时机是？我在onDestroy中调用总会报“Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.bluetooth.BluetoothGatt.close()' on a null object reference”这个错误。

一个是刷新cache，不好意想问下这个作用是？我也有尝试调用过，也会报空指针的错误。

还望赐教，谢谢！！

Start by reading the implementations and call sites for liteBluetooth.closeBluetoothGatt() and the cache refresh operation mentioned in the issue. Reproduce the NullPointerException from onDestroy and from refreshing the cache, then document or test the correct lifecycle and null-handling behavior.

Written by the indexing model from the issue text.