x/mobile: confusing "unsupported basic type" error when targeting Android

[Anyhasgone]

Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

->go version go1.9 linux/amd64

Does this issue reproduce with the latest release?

->yes

What operating system and processor architecture are you using (go env)?

->linux, amd64

What did you do?

->programmer

If possible, provide a recipe for reproducing the error.
A complete runnable program is good.
A link on play.golang.org is best.

What did you expect to see?

Please help me.Why unsupported basic type uint32 or uint64

What did you see instead?

the issues:
use gomobile bind -target=android/arm xxxx,and compile error
unsupported basic type: uint32
unsupported basic type: uint64

[mvdan]

I assume this is because gomobile is trying to generate Java code, and Java has no unsigned integer types. However, a quick google search doesn't give a definite answer, and the error message seems like this may be a bug or fixed at some point, rather than a design limitation.

Leaving it to @eliasnaur or someone else to decide if the error message should be improved. For example, something like "cannot use unsigned integer types on Java" for the uint16/32/64 errors.

[mvdan]

This doc page does leave unsigned integers out: https://godoc.org/golang.org/x/mobile/cmd/gobind#hdr-Type_restrictions

But it's still hard to reach it if one is googling for the error or searching for "uint", since neither appears on the page.

[gopherbot]

Change https://golang.org/cl/105377 mentions this issue: bind: ignore unsupported basic types