Question

我正在尝试将从MySQL检索到的日期与当前日期/时间进行比较。

我想要的效果是：

Date is Recent (Less than an hour)               | 0
Date is An Hour Ago (1-2 Hours before now)       | 1
Date is Several Hours Ago (2-8 Hours before now) | 2
Date is Yesterday (a day ago)                    | 3
Date is Recent (More than a day ago)             | 4

解释：该方法将返回0-4（含）之间的数字作为选择。

我目前的代码乱七八糟，但也许有人可以提出更好的方法？

compareDate方法：

private int compareDate(Date date1)
{
    long daysAgo = getDaysAgo(date1);

    if(daysAgo == 0)
    {
        //Check the hours

        int choice = getMinAgo(date1);

        //Code for "Minutes Ago"
        if(choice == 0)
        {
           return 0;
        }

        //Code for "An Hour Ago"
        else if(choice == 1)
        {
            return 1;
        }

        //Code for "Several Hours Ago"
        else if(choice == 2)
        {
            return 2;
        }

        else return -1;

    }

    else if (daysAgo == 1)
    {
        //"Code" for "Yesterday" is 3
        return 3;
    }

    else
    {
        //"Code" for "Several days ago" is 4
        return 4;
    }
}

getDaysAgo方法

private long getDaysAgo(Date date)
{
    long days = (new Date().getTime() - date.getTime()) / DAYS_IN_MILLISEC;

    return days;
}

getMinAgo方法

private int getMinAgo(Date date)
{
    long hourAgo = 60;
    long twoHourAgo = hourAgo*2;
    long eightHourAgo = hourAgo*8;

    Date dateHourAgo = new Date(date.getTime() - hourAgo*60*1000);
    Date dateTwoHourAgo = new Date(date.getTime() - twoHourAgo*60*1000);
    Date dateEightHourAgo = new Date(date.getTime() - eightHourAgo*60*1000);

    //Between 0-1 Hours Ago
    if(date.before(dateHourAgo))
    {
        return 0;
    }

    //Between 1-2 Hours Ago
    else if(date.after(dateHourAgo) && date.before(dateTwoHourAgo))
    {
        return 1;
    }

    else if(date.after(dateTwoHourAgo) && date.before(dateEightHourAgo))
    {
        return 2;
    }

    return -1;
}

Answer 1

下面的代码是一个如何实现该方法的示例（我将其命名为getChoice）。我测试过它并且工作正常。如果有什么不清楚，请不要犹豫和问。

import java.util.Date;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends Activity {

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

        Date testedDate = new Date(114, 4, 10, 22, 0, 0);
        TextView tv = (TextView)findViewById(R.id.textView1);

        int i = getChoice(testedDate);
        String mOutput = String.valueOf(i);

        tv.setText("The output is: " + mOutput);

    }

    private int getChoice(Date d) {
        long mTime = new Date().getTime() - d.getTime();

        if(mTime <= 3600000) return 0; // less than an hour
        if(mTime <= 7200000) return 1; // 1-2 hours before now
        if(mTime <= 28800000) return 2; // 2-8 hours before now
        if(mTime <= 86400000) return 3; // a day ago
        return 4; // more than a day ago
    }

}

Answer 2

我会从MySQL返回整数值，而不是编写大量代码。

（如果日期值是将来，或者日期为NULL，则不清楚您打算返回什么。）

SELECT t.datetime_col
     , CASE
       WHEN t.datetime_col > NOW() THEN -1                     -- in the future 
       WHEN t.datetime_col >= NOW() - INTERVAL  1 HOUR THEN 0  -- within the last hour
       WHEN t.datetime_col >= NOW() - INTERVAL  2 HOUR THEN 1  -- within the last two hours 
       WHEN t.datetime_col >= NOW() - INTERVAL  8 HOUR THEN 2  -- within the last eight hours
       WHEN t.datetime_col >= NOW() - INTERVAL 24 HOUR THEN 3  -- within the past day
       WHEN t.datetime_col <  NOW() - INTERVAL 24 HOUR THEN 4  -- older than a day 
       END AS recent
     , ...
  FROM ...

Android：比较日期

2 个答案: