数据库查询后 Flutter futurebuilder 快照为空，直到热重载

如何解决数据库查询后 Flutter futurebuilder 快照为空，直到热重载

我正在查询数据库以在构建方法中填充列表视图，但未来的构建器在首次运行时在快照中返回 null。它给出 RangeError (index): Invalid value: Valid value range is empty。但是当我按下热重载时，数据显示正确。我想我无法将快照结果正确映射到 juzlist，请帮助我缺少什么？

ERROR: Task (/data/Projects/Project1/layers/oe-core/Meta/recipes-
kernel/linux-libc-headers/linux-libc-headers_5.2.bb:do_package) Failed with exit code '1'
NOTE: Tasks Summary: Attempted 1641 tasks of which 0 didn't need to be rerun and 4 Failed.

Summary: 4 tasks Failed:
  /data/Projects/Project1/layers/oe-core/Meta/recipes-core/base-files/base-files_3.0.14.bb:do_package
  /data/Projects/Project1/layers/oe-core/Meta/recipes-extended/shadow/shadow-securetty_4.6.bb:do_package
  /data/Projects/Project1/layers/oe-core/Meta/recipes-core/os-release/os-release.bb:do_package
 /data/Projects/Project1/layers/oe-core/Meta/recipes-kernel/linux-libc-headers/linux-libc-headers_5.2.bb:do_package
Summary: There were 6 WARNING messages shown.
Summary: There were 4 ERROR messages shown,returning a non-zero exit code.