You can use a SweepGradient
to get a radial gradient:
Shader s = new SweepGradient(0, 0, new int[] { 0xFF33B5E5,0xFFFFFFFF }, null);
//or if you only use two colors:
Shader s = new SweepGradient(0, 0, 0xFF33B5E5, 0xFFFFFFFF);
To avoid filling, just use the Paint.Style.STROKE
style, with appropriate strokeWidth
.