Flutter 范围错误：无效值：....，包含：-1

Question

What does "Inclusive: -1" mean in a Range Error RangeError (index): Invalid Value: Not in range 0..6, inclusive: -1

Note: index is the argument from

ListView.builder(
  itemBuilder: (context,index) => Widget,
)

Answer 1

The misleading comma is causing you to misparse the error message. The "inclusive" part is meant to describe the range, not the invalid value. That is, the error would have been better written as:

RangeError (index): Invalid Value: -1 not in range 0..6 (inclusive)

or

RangeError (index): Invalid Value: -1 not in range [0, 6]

Somewhere you're passing -1 as an index into a list that has 7 elements.

( https://github.com/dart-lang/sdk/issues/29586 requests that the error message be improved.)

Answer 2

I was able to fix it by going to the projects root directory and running the command

flutter clean

... I was experiencing the issue on iOS.