[Mobile] numbers input can't be negative

[guillaume4]

Hey,

I want users to be able to experience my application fully on smartphones and computers,
The version I use for computers work well but I have few issues with the phone one.

For example, if I want users to be able to indicate a loss of money (negative decimal input, with a decimal place of 2), the keyboard shown on phone looks like this:

Is there any solution to it ?
How are we able to input negative numbers on phone ?

Thanks a lot