It is not good idea to construct path object every time when call Draw method. Is it better to keep path object and clear/set points every time?
Update: One more question - what is difference between 'reset' and 'rewind' path object?
Yes, it is better to reset the path and set the points rather than instatiating a new one. This prevents excessive allocation of memory, which can lead to frequent garbage collection. When the GC runs the graphics may pause for a moment, especially on older devices so you want to keep this to a minimum.
The reset() and rewind() methods both have pretty much the same effect, except that rewind() keeps the internal data structure intact, which can improve performance particularly if your path always has the same number of points.
来源：https://stackoverflow.com/questions/12530684/android-draw-path