public SliceValue getValueForAngle(int angle, SelectedValue selectedValue) {
        final PieChartData data = dataProvider.getPieChartData();
        final float touchAngle = (angle - rotation + 360f) % 360f;
        final float sliceScale = 360f / maxSum;
        float lastAngle = 0f;
        int sliceIndex = 0;
        for (SliceValue sliceValue : data.getValues()) {
            final float tempAngle = Math.abs(sliceValue.getValue()) * sliceScale;
            if (touchAngle >= lastAngle) {
                if (null != selectedValue) {
                    selectedValue.set(sliceIndex, sliceIndex, SelectedValueType.NONE);
                }
                return sliceValue;
            }
            lastAngle += tempAngle;
            ++sliceIndex;
        }
        return null;
    }
Returns SliceValue that is under given angle, selectedValue (if not null) will be hold slice index.
hellocharts-library/src/lecho/lib/hellocharts/renderer/PieChartRenderer.java