Alarm Only Goes Off At The Set Date But Ignores The Set Time When Using Alarm Manager In Android

Question

I've developed an application where a Text appears on screen whenever the current time matches the date and time selected by the user. This is accomplished using Alarm Manager. The date and time are selected using the built in DatePicker and TimePicker composables. However, there is a problem. The Alarm Manager event only triggers when the current date matches the selected date. It does not account for the time.

Here is a break down of the application. There is a column that contains four Composables. The first one is a Text, the other is a DatePicker, the second one is a TimeInput, and the last one is a Button. There is a Broadcast Receiver called AlarmReceiver. There is an empty String variable not located inside of any Class or Activity that holds the value for the Text Composable.

Here is the code in the MainActivity. It forms the user interface and holds the logic for the AlarmReceiver.

// Variable That Holds The Date Picker State
var daterPickState = rememberDatePickerState(
    initialSelectedDateMillis = LocalDate.now() // Initial Selected Date Is The Current Date
)

// Variable That Holds The Time Picker State
var timePickerState = rememberTimePickerState(
    initialHour = LocalTime.now().hour, // Initial Selected Hour Is The Current Hour
    initialMinute = LocalTime.now().minute, // Initial Selected Minute Is The Current Minute
    is24Hour = false // The Time Picker Is In AM And PM Format
)

// Variable That Holds Alarm Manager
val alarmManager = getSystemService(Context.ALARM_SERVICE) as AlarmManager

// Variable That Holds Alarm Intent
val alarmIntent = Intent(this, AlarmReceiver::class.java)

// Variable That Holds Pending Intent
val pendingIntent = PendingIntent.getBroadcast(
applicationContext, // Context
0, // Request Code
alarmIntent, // Intent
PendingIntent.FLAG_UPDATE_CURRENT // Flag
)

// Variable That Holds The Selected The Date And Divides It Into Year, Month, And Day
var selectedDate = Instant.ofEpochMilli(datePickState.selectedDateMillis!!)
.atZone(ZoneId.systemDefault()).toLocalDate() // The Values Are Converted Into An Integer

// Variable That Convert The Date And Time Into A Long
var selectedDateTime = LocalDateTime.of(
    selectedDate.year, // Year
    selectedDate.monthValue, // Month
    selectedDate.dayOfMonth, // Day Of The Month
    timePickState.hour, // Hour
    timePickState.minute // Minute
).atZone(ZoneId.systemDefault()).toInstant().toEpochMilli() // Long Conversion Logic

// Layout For The Application
Column(
   modifier = Modifier.fillMaxSize(), // Column Fills Entire Screen
   horizontalAlignment = Alignment.CenterHorizontally, // Contents Are Centered Horizontally
   verticalArrangement = Arrangement.Center // Contents Are Centered Vertically
) {

// Text That Gets Displayed When The Current Date & Time Matches The Set Date & Time
Text(text = text)

// Date Picker
DatePicker(state = datePickerState) // DatePickerState Is Passed Into The State Parameter

// Time Picker
TimeInput(state = timePickerState) TimePickerState Is Passed Into The State Parameter

// Button That Sets The Alarm Manager Event
Button(
   onClick = {
      // Instance of Alarm Manager
      alarmManager.setExact(
         AlarmManager.RTC_WAKEUP, // Alarm Type
         selectedDateTime, // When To Trigger Alarm Converted In Milliseconds
         pendingIntent // Pending Intent
)
}
){ Text(text = "Set Alarm Event") } // Button Text
}

Here is the empty String variable that holds the value for the Text that appears when the Alarm Manager event goes off.

var text by mutableStateOf("")

Here is the Broadcast Receiver. It is registered in the Android Manifest file.

// Alarm Broadcast Receiver
class AlarmReceiver : BroadcastReceiver() {
    override fun onReceive(context: Context, intent: Intent) {
        
        text = "It Works!" // The Text Is Changed To "It Works!"
    }
}

As stated above the Alarm Manager only triggers at the set date. It ignores the time. This problem only occurs with the DatePicker and TimePicker Composables. If I hard code the date and time into the Alarm Manager everything works fine. If I only use the TimePicker and not the DatePicker it also works fine. That would mean the problem has something to do with the DatePicker but I don't know what.