как отключить или не щелкнуть календарную дату до текущей даты? [Дубликат]

См. этот пример ..!

import java.util.Calendar;
import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;

public class MyAndroidAppActivity extends Activity {

    private TextView tvDisplayDate;

    private Button btnChangeDate;

    private int myear;
    private int mmonth;
    private int mday;

    static final int DATE_DIALOG_ID = 999;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        setCurrentDateOnView();
        addListenerOnButton();

    }

    // display current date
    public void setCurrentDateOnView() {

        tvDisplayDate = (TextView) findViewById(R.id.tvDate);       

        final Calendar c = Calendar.getInstance();
        myear = c.get(Calendar.YEAR);
        mmonth = c.get(Calendar.MONTH);
        mday = c.get(Calendar.DAY_OF_MONTH);

        // set current date into textview
        tvDisplayDate.setText(new StringBuilder()
                // Month is 0 based, just add 1
                .append(mmonth + 1).append("-").append(mday).append("-")
                .append(myear).append(" "));
    }

    public void addListenerOnButton() {

        btnChangeDate = (Button) findViewById(R.id.btnChangeDate);

        btnChangeDate.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                showDialog(DATE_DIALOG_ID);

            }

        });

    }

    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {
        case DATE_DIALOG_ID:
            // set date picker as current date
            DatePickerDialog _date =   new DatePickerDialog(this, datePickerListener, myear,mmonth,
                    mday){
                @Override
                public void onDateChanged(DatePicker view, int year, int monthOfYear, int dayOfMonth)
                {   
                    if (year < myear)
                        view.updateDate(myear, mmonth, mday);

                    if (monthOfYear < mmonth && year == myear)
                        view.updateDate(myear, mmonth, mday);

                    if (dayOfMonth < mday && year == myear && monthOfYear == mmonth)
                        view.updateDate(myear, mmonth, mday);

                }
            };
            return _date;
        }
        return null;
    }

    private DatePickerDialog.OnDateSetListener datePickerListener = new DatePickerDialog.OnDateSetListener() {

        // when dialog box is closed, below method will be called.
        public void onDateSet(DatePicker view, int selectedYear,
                int selectedMonth, int selectedDay) {
            myear = selectedYear;
            mmonth = selectedMonth;
            mday = selectedDay;

            // set selected date into textview
            tvDisplayDate.setText(new StringBuilder().append(mmonth + 1)
                    .append("-").append(mday).append("-").append(myear)
                    .append(" "));    

        }
    };

}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/btnChangeDate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Change Date" />

    <TextView
        android:id="@+id/lblDate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Current Date (M-D-YYYY): "
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <TextView
        android:id="@+id/tvDate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceLarge" />

</LinearLayout>