using UnityEngine;
using System.Collections;

public class SelectedDate {
    public static System.DateTime date = System.DateTime.Now;
}
public class DateCallback : AndroidJavaProxy
{
    public DateCallback() : base("android.app.DatePickerDialog$OnDateSetListener") { }

    public void onDateSet(AndroidJavaObject view, int year, int monthOfYear, int dayOfMonth) {
        SelectedDate.date = new System.DateTime(year, monthOfYear + 1, dayOfMonth);
    }
}
public class ExampleClass : MonoBehaviour 
{
    private AndroidJavaObject activity; 
	
    void PickDate(){
        new AndroidJavaObject("android.app.DatePickerDialog", activity, new DateCallback(), SelectedDate.date.Year, SelectedDate.date.Month - 1, SelectedDate.date.Day).Call("show");
    }
	
    void OnGUI() 
    {
        if (GUI.Button(new Rect(10, 10, 450, 100), System.String.Format("{0:yyyy-MM-dd}", SelectedDate.date))) 
        {
            activity = new AndroidJavaClass("com.unity3d.player.UnityPlayer").GetStatic<AndroidJavaObject>("currentActivity");
            activity.Call("runOnUiThread", new AndroidJavaRunnable(PickDate));
        }
    }
}