How to put the selected hourOfDay and minute into one variable to make comparison with current time?

I'm trying to make a if-else statement that if user put time which have past, it will alert the user that the time has past. And I also unable to set the timedialogpicker to the current time when the user open it. Thanks in advance.

The code:

button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Calendar timeNow = Calendar.getInstance();
        timePickerDialog = new TimePickerDialog(MainActivity.this, new TimePickerDialog.OnTimeSetListener() {
            @Override
            public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
                int currHour = calendar.get(Calendar.HOUR_OF_DAY);
                int currMin = calendar.get(Calendar.MINUTE);
                Time currTime = new Time(currHour, currMin); //This part display error
                if (currTime.getTimeInMillis() >= timeNow.getTimeInMillis()) { //This part display error
                    //it's after current
                    int hour = hourOfDay % 12;
                } else {
                    //it's before current'
                    Toast.makeText(getApplicationContext(), "Invalid Time", Toast.LENGTH_LONG).show();
                }
                time = "";
                time = hourOfDay+":"+minute;

                Userbook book = new Userbook(temp, time);

                db.collection("Booking").add(book).addOnSuccessListener(new OnSuccessListener<DocumentReference>() {
                    @Override
                    public void onSuccess(DocumentReference documentReference) {
                        Toast.makeText(MainActivity.this, "Note saved", Toast.LENGTH_SHORT).show();
                    }
                }).addOnFailureListener(new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {
                        Toast.makeText(MainActivity.this, "Error", Toast.LENGTH_SHORT).show();
                    }
                });
               Toast.makeText(MainActivity.this, "Time is "+currHour+":"+currMin, Toast.LENGTH_SHORT).show();
            }
        },timeNow.get(Calendar.HOUR_OF_DAY), timeNow.get(Calendar.MINUTE),false);
        timePickerDialog.show();
    }
});

In brief: ! LocalTime.of( 10 , 20 ).isBefore( LocalTime.now() )

! LocalTime#isBefore

The java.time API, released with Java-8 in March 2014, supplanted the error-prone legacy date-time API. Since then, it has been strongly recommended to use this modern date-time API.

You can use LocalTime#of(int hour, int minute) to get an instance of LocalTime with the given hour and minute values and then compare it with the current time (i.e. LocalTime#now) using LocalTime#isBefore.

Demo:

import java.time.LocalTime;

public class Main {
    public static void main(String[] args) {
        LocalTime now = LocalTime.now();

        // Sample hour and minute values
        int hour = 10;
        int minute = 20;

        LocalTime givenTime = LocalTime.of(hour, minute);

        System.out.println(!givenTime.isBefore(now));
    }
}

Output:

false

!givenTime.isBefore(now) means givenTime is either equal to or after now.

Learn more about the modern Date-Time API from Trail: Date Time.