Ranges for radius in shadowRadius and visiblity in TextView

问题

I'd like to know what is the exact range of the radius in the shadowRadius property. In the documentation, they only say this value must be a float. That's fine but what is the range for the radius in Android? I mean, how do I set a 120º radius for instance?

Same problem for the visibility for TextView. In the documentation, they say I have to set a #aarrggbb hexadecimal color code. That's fine but again, what is the range for the visibility in Android? The value 100 (= 64 in hexadecimal) doesn't correspond at all to a maximum opacity. So what are the minimum / maximum opacities in Android?

回答1:

Radius is a length not an angle and the range of opacity is 00 to FF using #aarrggbb.

回答2:

There is an undocumented range-limit on the shadowRadius property on some devices: 0-25.

If you exceed 25 on the Lenovo A3500 tablet for example, the following will show up in LogCat:

E/rsC++(14127): RS CPP error: Blur radius out of 0-25 pixel bound
E/rsC++(14127): RS CPP error (masked by previous error): Allocation creation failed
E/rsC++(14127): RS CPP error (masked by previous error): Allocation creation failed

And your app will terminate hard without throwing an exception that you could react to.

Gotta love the way Android handles these things...

(Also see this question: Android - Signal 11, RS CPP error: Blur radius out of 0-25 pixel bound)

来源：https://stackoverflow.com/questions/4866928/ranges-for-radius-in-shadowradius-and-visiblity-in-textview