android - 在日期选择器中计算 50 天

Question

如何从在 andriod 的日期选择器中输入的天数计算 50 天。

示例 如果用户选择 2013 年 2 月 23 日，那么从 xx/xx/xxxx 开始的第 50 天会是什么？第 100 天 第 200 天，就像明智的第 1000 天一样，请在这个逻辑上帮助我

Answer 1

据我了解你的问题，你可以尝试做这样的事情：

// this const is 24 hours in milliseconds: 24 hours in day, 60 min. in one hour, 60 sec. in one min., 1000 ms. in one sec.
private static final int TWENTY_FOUR_HOURS = 24 * 60 * 60 * 1000;
//...
Date dateYouChose;
Date dateYouChosePlus50Days = new Date(dateYouChose.getTime() + (50 * TWENTY_FOUR_HOURS));

更新：

所以，也许它对你有好处（但要小心，我没有测试这段代码，也许我犯了一些错误）：

final DatePicker datePicker;

final Button btnDisplayCelebrationTimes;

final TextView txtDatePlus50;
final TextView txtDatePlus100;

// ...

btnDisplayCelebrationTimes.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {
        final SimpleDateFormat dateFormat = new SimpleDateFormat("dd.MM.yyyy");

        final GregorianCalendar gregorianCalendar;

        gregorianCalendar = new GregorianCalendar(datePicker.getYear(), datePicker.getMonth(),
                datePicker.getDayOfMonth());
        gregorianCalendar.add(Calendar.DAY_OF_MONTH, 50);
        final Date datePlus50 = gregorianCalendar.getTime();

        txtDatePlus50.setText(dateFormat.format(datePlus50));

        gregorianCalendar = new GregorianCalendar(datePicker.getYear(), datePicker.getMonth(),
                datePicker.getDayOfMonth());
        gregorianCalendar.add(Calendar.DAY_OF_MONTH, 100);
        final Date datePlus100 = gregorianCalendar.getTime();

        txtDatePlus100.setText(dateFormat.format(datePlus100));
    }
});

Answer 2

使用以下简单代码动态添加日期。

int Days = 50; // this is the input . you can change it in argument. the format of the date also changeable as per your requirement. 

        try
        {
        Date date = null;
        String str = "2013-06-04";          
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");    
        date = formatter.parse(str);
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(Calendar.DATE,Days );      
        System.out.println("" + formatter.format(calendar.getTime()));
        }
        catch (Exception e)
        {
            e.printStackTrace();   
        }

希望这对您有所帮助。

编辑 。

嗨，这是完整的工作代码。

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

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 DatePicker dpResult;
    private Button btnChangeDate;

    private int year;
    private int month;
    private int day;

    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);
        dpResult = (DatePicker) findViewById(R.id.dpResult);

        final Calendar c = Calendar.getInstance();
        year = c.get(Calendar.YEAR);
        month = c.get(Calendar.MONTH);
        day = c.get(Calendar.DAY_OF_MONTH);

        // set current date into textview
        tvDisplayDate.setText(new StringBuilder()
                // Month is 0 based, just add 1
                .append(month + 1).append("-").append(day).append("-")
                .append(year).append(" "));

        // set current date into datepicker
        dpResult.init(year, month, day, null);

    }

    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
            return new DatePickerDialog(this, datePickerListener, year, month,
                    day);
        }
        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) {
            year = selectedYear;
            month = selectedMonth;
            day = selectedDay;

            String str= year+"-"+(month+1)+"-"+day;
            System.out.println(" rrrrrr " +str);
            tvDisplayDate.setText(str); // this is the current date. 

            tvDisplayDate.setText(" Old Date" + str + "After adding 50 days" +dateadding(50, str) );
            // set selected date into datepicker also
            dpResult.init(year, month, day, null);

        }
    };

    String dateadding(int DaystoAdd,String Date)
    {
        int Days = DaystoAdd; // this is the input . you can change it in argument. the format of the date also changeable as per your requirement. 
String finaldate="";
        try
        {
        Date date = null;
        String str = Date;          
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");    
        date = formatter.parse(str);
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(Calendar.DATE,Days );      
        finaldate= formatter.format(calendar.getTime());
        }
        catch (Exception e)
        {
            e.printStackTrace();   
        }
        return finaldate;
    }


}

设计线

<?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" />

    <DatePicker
        android:id="@+id/dpResult"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>