1.導入Gson與okhttp

dependencies {
    implementation 'com.contrarywind:Android-PickerView:4.1.9'
}

2.程式碼

package com.example.datepicker

import android.annotation.SuppressLint
import android.os.Bundle
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import com.bigkoo.pickerview.builder.OptionsPickerBuilder
import com.bigkoo.pickerview.listener.OnOptionsSelectListener
import com.bigkoo.pickerview.view.OptionsPickerView
import kotlinx.android.synthetic.main.activity_main.*
import java.text.SimpleDateFormat
import java.util.*

class MainActivity : AppCompatActivity() {

    private var year = mutableListOf<String>()
    private var month = mutableListOf<String>()
    private var day = mutableListOf<String>()
    var nowYear: Int = 0
    var nowMonth: Int = 0
    var nowDay: Int = 0
    lateinit var datePicker: OptionsPickerView<String>
    lateinit var calendar : Calendar

    @SuppressLint("SimpleDateFormat")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        calendar = Calendar.getInstance()

        chocie.setOnClickListener {
            year.clear()
            month.clear()
            day.clear()
            getDate()

            datePicker = OptionsPickerBuilder(this,
                OnOptionsSelectListener { choiceYear, choiceMonth, choiceDay, _ ->
                    var newYear = (choiceYear+1).toString()
                    var newMonth = (choiceMonth+1).toString()
                    var newDay = (choiceDay+1).toString()

                    if (newYear.length < 3) {
                        newYear = "0newYear"
                    }

                    if (newMonth.length == 1) {
                        newMonth = "0newMonth"
                    }

                    if (newDay.length == 1) {
                        newDay = "0newDay"
                    }

                    date.text = "newYear/newMonth/newDay"
                    year.clear()
                    month.clear()
                    day.clear()

                }).setOptionsSelectChangeListener { options1, options2, options3 ->
                calendar.set(Calendar.YEAR, options1 + 1912)
                calendar.set(Calendar.MONTH, options2)
                calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH))

                val format = SimpleDateFormat("dd")
                val endDate = format.format(calendar.time)
                changeTheDay(endDate.toInt(), options1, options2, options3)
            }
                .setSubmitText("確定")
                .setContentTextSize(20)
                .build()

            datePicker.setNPicker(year, month, day)
            datePicker.setSelectOptions(nowYear, nowMonth -1 ,nowDay)
            datePicker.show()
        }
    }

    private fun getDate() {
        nowYear = Calendar.getInstance().get(Calendar.YEAR) - 1911
        Log.d("123", nowYear.toString())
        for (i in 1..nowYear) {
            year.add("民國{i}年")
        }

        nowMonth = Calendar.getInstance().get(Calendar.MONTH) + 1
        for (i in 1..12) {
            month.add("{i}月")
        }

        nowDay = Calendar.getInstance().get(Calendar.DAY_OF_MONTH)
        for (i in 1..nowDay) {
            day.add("{i}日")
        }
    }

    private fun changeTheDay(thisDay: Int, options1: Int, options2: Int, options3: Int) {
        day.clear()
        for (i in 1..thisDay) {
            day.add("i 日")
        }

        datePicker.setNPicker(year, month, day)
        datePicker.setSelectOptions(options1, options2, options3)
    }
}