Die Anleitung zu Android DatePickerDialog

int selectedYear = 2000;
int selectedMonth = 5;
int selectedDayOfMonth = 10;

// Date Select Listener.
DatePickerDialog.OnDateSetListener dateSetListener = new DatePickerDialog.OnDateSetListener() {

    @Override
    public void onDateSet(DatePicker view, int year,
                          int monthOfYear, int dayOfMonth) {

        editTextDate.setText(dayOfMonth + "-" + (monthOfYear + 1) + "-" + year);
    }
};

// Create DatePickerDialog (Spinner Mode):
DatePickerDialog datePickerDialog = new DatePickerDialog(this,
            dateSetListener, selectedYear, selectedMonth, selectedDayOfMonth);

// Show
datePickerDialog.show();

int selectedYear = 2000;
int selectedMonth = 5;
int selectedDayOfMonth = 10;

// Date Select Listener.
DatePickerDialog.OnDateSetListener dateSetListener = new DatePickerDialog.OnDateSetListener() {

    @Override
    public void onDateSet(DatePicker view, int year,
                          int monthOfYear, int dayOfMonth) {

        editTextDate.setText(dayOfMonth + "-" + (monthOfYear + 1) + "-" + year);
    }
};

// Create DatePickerDialog (Spinner Mode):
DatePickerDialog datePickerDialog = new DatePickerDialog(this,
            android.R.style.Theme_Holo_Light_Dialog_NoActionBar,
            dateSetListener, selectedYear, selectedMonth, selectedDayOfMonth);

// Show
datePickerDialog.show();

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    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:layout_height="match_parent"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/editText_date"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="90dp"
        android:ems="10"
        android:inputType="date"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button_date"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="90dp"
        android:text="Select Date"
        app:layout_constraintStart_toEndOf="@+id/editText_date"
        app:layout_constraintTop_toTopOf="parent" />

    <CheckBox
        android:id="@+id/checkBox_isSpinnerMode"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="16dp"
        android:text="Spinner Mode?"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editText_date" />
</androidx.constraintlayout.widget.ConstraintLayout>

package org.o7planning.datepickerdialogexample;

import androidx.appcompat.app.AppCompatActivity;

import android.app.DatePickerDialog;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.DatePicker;
import android.widget.EditText;

import java.util.Calendar;

public class MainActivity extends AppCompatActivity {

    private EditText editTextDate;
    private Button buttonDate;
    private CheckBox checkBoxIsSpinnerMode;

    private int lastSelectedYear;
    private int lastSelectedMonth;
    private int lastSelectedDayOfMonth;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        this.editTextDate = (EditText) this.findViewById(R.id.editText_date);
        this.buttonDate = (Button) this.findViewById(R.id.button_date);
        this.checkBoxIsSpinnerMode = this.findViewById(R.id.checkBox_isSpinnerMode);

        this.buttonDate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                buttonSelectDate();
            }
        });

        // Get Current Date
        final Calendar c = Calendar.getInstance();
        this.lastSelectedYear = c.get(Calendar.YEAR);
        this.lastSelectedMonth = c.get(Calendar.MONTH);
        this.lastSelectedDayOfMonth = c.get(Calendar.DAY_OF_MONTH);
    }

    // User click on 'Select Date' button.
    private void buttonSelectDate() {
        final boolean isSpinnerMode = this.checkBoxIsSpinnerMode.isChecked();

        // Date Select Listener.
        DatePickerDialog.OnDateSetListener dateSetListener = new DatePickerDialog.OnDateSetListener() {

            @Override
            public void onDateSet(DatePicker view, int year,
                                  int monthOfYear, int dayOfMonth) {

                editTextDate.setText(dayOfMonth + "-" + (monthOfYear + 1) + "-" + year);

                lastSelectedYear = year;
                lastSelectedMonth = monthOfYear;
                lastSelectedDayOfMonth = dayOfMonth;
            }
        };

        DatePickerDialog datePickerDialog = null;

        if(isSpinnerMode)  {
            // Create DatePickerDialog:
            datePickerDialog = new DatePickerDialog(this,
                    android.R.style.Theme_Holo_Light_Dialog_NoActionBar,
                    dateSetListener, lastSelectedYear, lastSelectedMonth, lastSelectedDayOfMonth);
        }
        // Calendar Mode (Default):
        else {
            datePickerDialog = new DatePickerDialog(this,
                    dateSetListener, lastSelectedYear, lastSelectedMonth, lastSelectedDayOfMonth);
        }

        // Show
        datePickerDialog.show();
    }
}