atDrawFrame top-level property

bool get atDrawFrame

当框架正在处理下一帧持久回调时（build/layout/paint），它将返回 true，当你在此阶段调用 setState 时， Flutter 框架将会抛出异常：setState() or markNeedsBuild() called during build.

Implementation

bool get atDrawFrame =>
    SchedulerBinding.instance.schedulerPhase ==
    SchedulerPhase.persistentCallbacks;