Hi yutthanain,
Since you have set dateSelectedAsCircle = true, the dateBkUnderlineSelected has no effect as its only used for rectangle selection. In this case, you must set only the dateBkSelected as shown below based on your example :
local op = { top = 100, left = 10, wDialog = display.contentWidth-20, hDialog = 400, overideBkInput = true, overideBkColor = {0,0,0,0.8}, templateStyle = "classic", dateNumberFontSize = 20, dateSelectedAsCircle = true, weekEndNumberColor = {1,0,0}, selectDays = "2017-5-18,2017-4-19,2017-4-20,2017-4-21", dateBkSelected = {1,0,0,1}, buttonHandler = onClickDate }
The dateBkUnderlineSelected is useful to a nicer selection visual when using the rectangle selection as it offer you 2 level of colors. Try the example below >>
local op = { top = 100, left = 10, wDialog = display.contentWidth-20, hDialog = 400, overideBkInput = true, overideBkColor = {0,0,0,0.8}, templateStyle = "classic", dateNumberFontSize = 20, weekEndNumberColor = {1,0,0}, selectDays = "2017-5-18,2017-4-19,2017-4-20,2017-4-21", dateBkUnderlineSelected = {1,0,0,1}, dateBkSelected = {1,0,0,0.2}, buttonHandler = onClickDate }
You can also use some predefined color scheme like the grey one also for quicker result :
local op = { top = 100, left = 10, wDialog = display.contentWidth-20, hDialog = 400, overideBkInput = true, overideBkColor = {0,0,0,0.8}, templateStyle = "classic", colorStyle = "grey", dateNumberFontSize = 20, selectDays = "2017-5-18,2017-4-19,2017-4-20,2017-4-21", buttonHandler = onClickDate }
I hope this help you,
Nick