Accessing hidden field violation - ScaleGestureDetector

[LukasPaczos]

Refs. mapbox/mapbox-gl-native#11625.
Android P introduces new restrictions when it comes to accessing private and hidden methods and fields within the SDK, see the preview note.

#30 uses reflection to access private fields and we need to workaround that in preparation for the Android P release.

There is already an issue tracked on the Google's issue board regarding settable span values for the ScaleGestureDetector, I'm not really sure about chances of it being adressed.

/cc @tobrun

[LukasPaczos]

Noting here that since the release of the Android Pie, the hidden field access violation has been moved to the light greylist:

Accessing hidden field Landroid/view/View;->mAccessibilityDelegate:Landroid/view/View$AccessibilityDelegate; (light greylist, reflection)

[flavienbwk]

Problem is still active.

[LukasPaczos]

Noting that in the Android Q beta reflection on this particular part of the code has been moved to the "dark greylist":

Accessing hidden field Landroid/view/ScaleGestureDetector;->mMinSpan:I (greylist-max-p, reflection)
Accessing hidden field Landroid/view/ScaleGestureDetector;->mSpanSlop:I (greylist-max-p, reflection)

which based on the docs:

Similarly, if a greylisted non-SDK interface was not restricted in Android Pie but is now restricted in Android Q, that interface is part of the greylist-max-p list, where “p” stands for Pie or Android 9 (API level 28).

means that if the app targets Android Q or above, the workaround is going to result in no-op/exception.

Since there's no movement in the ticket tracking the span in the scale gesture detector, I think we're forced to roll out our own implementation by the time Android Q is officially released.