App is crashing on clicking the OK button of date dialogue box after selecting the date !! There're no errors showing in the code. What's the problem ?

// MainActivity.kt file.

package com.nandini.android.dobcalc

import android.app.DatePickerDialog
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.TextView
import android.widget.Toast
import java.text.SimpleDateFormat
import java.util.*

class MainActivity : AppCompatActivity() {

   private var dateTv : TextView?=null
    private var minTv : TextView?=null

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

        val btnDatePicker : Button = findViewById(R.id.btnDatePicker)
        dateTv=findViewById(R.id.date_tv)
        minTv=findViewById(R.id.min_tv)

        btnDatePicker.setOnClickListener {
         datePicker()
        }

    }

    private fun datePicker ()
    {
        val myCalender = Calendar.getInstance()
        val year = myCalender.get(Calendar.YEAR)
        val month = myCalender.get(Calendar.MONTH)
        val day = myCalender.get(Calendar.DAY_OF_MONTH)

        val dpd = DatePickerDialog(this,
            { _, selectedYear, selectedMonth, selectedDay ->
                Toast.makeText(this,"Year was $selectedYear , ${selectedMonth 1}'s $selectedDay day.",Toast.LENGTH_SHORT).show()

                val selectedDate="$selectedDay . ${selectedMonth 1} . $selectedYear"
                dateTv?.text = selectedDate
                val sdf= SimpleDateFormat("dd/MM/yyyy",Locale.ENGLISH)
                val theDate=sdf.parse(selectedDate)

                theDate?.let {

                    val selectedDateInMin=theDate.time / 60000
                    val currentDate=sdf.parse(sdf.format(System.currentTimeMillis()))

                    currentDate?.let {

                        val currentDateInMin=currentDate.time/60000
                        val differenceInMin = currentDateInMin-selectedDateInMin
                        minTv?.text=differenceInMin.toString()
                    }

                } },year,month,day)
            dpd.datePicker.maxDate=System.currentTimeMillis()-86400000
            dpd.show()


    }
}

// activity_main.xml file having linear layout as parent.

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:background="@color/bgColor"
    android:orientation="vertical"
    android:gravity="center_horizontal"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@ id/txt1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Calculate your"
        android:textSize="25sp"
        android:textStyle="bold"
        android:textAllCaps="true"
        android:layout_marginTop="16dp"
        android:textColor="@color/txtColor" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Age"
        android:textSize="25sp"
        android:padding="10dp"
        android:background="@color/txtBg"
        android:textStyle="bold"
        android:textAllCaps="true"
        android:layout_marginTop="16dp"
        android:textColor="@color/txtColor" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="In Minutes"
        android:textSize="25sp"
        android:textStyle="bold"
        android:textAllCaps="true"
        android:layout_marginTop="16dp"
        android:textColor="@color/txtColor" />

    <Button
        android:id="@ id/btnDatePicker"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:backgroundTint="#D9EADD"
        android:layout_margin="16dp"
        android:text="Select Date"
        android:textStyle="bold"
        android:textSize="18sp"
        android:textColor="@color/txtBg"/>

    <TextView
        android:id="@ id/date_tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="00.00.00"
        android:layout_marginTop="16dp"
        android:textAllCaps="true"
        android:textColor="@color/txtColor"
        android:textSize="20sp"
        android:textStyle="bold" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="In Minutes"
        android:textSize="20sp"
        android:textStyle="bold"
        android:textAllCaps="false"
        android:layout_marginTop="8dp"
        android:textColor="#98B0A8" />

    <TextView
        android:id="@ id/min_tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="0"
        android:textSize="35sp"
        android:textStyle="bold"
        android:textAllCaps="true"
        android:layout_marginTop="25dp"
        android:textColor="@color/txtColor" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="In Minutes"
        android:textSize="25sp"
        android:textStyle="bold"
        android:textAllCaps="false"
        android:layout_marginTop="8dp"
        android:textColor="#98B0A8" />

</LinearLayout>

Added date picker , used Calendar class and take dates as input & convert the difference of current date and selected date in minutes.

CodePudding user response：

The exact error is in this code block.

val selectedDate="$selectedDay . ${selectedMonth 1} . $selectedYear"
dateTv?.text = selectedDate
val sdf= SimpleDateFormat("dd/MM/yyyy",Locale.ENGLISH)
val theDate=sdf.parse(selectedDate)

You have defined SimpleDateFormat as dd/MM/yyyy, but providing wrong date format as input to sdf. selectedDate variable contain this format dd . MM . yyyy, so it's throwing error.

Try to assign selectedDate variable with the correct date format.

val selectedDate = "$selectedDay/${selectedMonth 1}/$selectedYear"