如何使用SimpleDateFormat.parse（）将Calendar.toString（）转换为日期？ [英] How can I Convert Calendar.toString() into date using SimpleDateFormat.parse()?

问题描述

我正在开发一个使用数据库的Android应用，每当用户插入新的寄存器时，使用

<$ p将当前数据和时间保存在db中。 $ p> 日历cal = Calendar.getInstance（）;


所以，当我从数据库中检索数据时，得到了这样的字符串：

java.util.GregorianCalendar [time = 1496007575129，areFieldsSet = true，lenient = true，zone = America / Mexico_City，firstDayOfWeek = 1，minimalDaysInFirstWeek = 1， ERA = 1，YEAR = 2017，MONTH = 4，WEEK_OF_YEAR = 22，WEEK_OF_MONTH = 5，DAY_OF_MONTH = 28，DAY_OF_YEAR = 148，DAY_OF_WEEK = 1，DAY_OF_WEEK_IN_MONTH = 4，AM_PM = 1，HOUR = 4，HOUR_OF_DAY = 16，MINUTE 39，SECOND = 35，MILLISECOND = 129，ZONE_OFFSET = -21600000，DST_OFFSET = 3600000]

当我尝试将其转换时会出现问题使用SimpleDateFormat.parse将其显示在RecyclerView中的字符串，我总是得到相同的日期：09/04/2017。

这是我的RecViewAdapter.java中的代码：

  @Override 
 public void onBindViewHolder（ViewHolderholder，int position）{
 items.moveToPosition（position ）; 
 
字符串s，d，p，f; 
 
 
 s = items.getString（ConsultaTomas.SISTOLICA）; 
holder.systolica.setText（s）; 
 
 d = items.getString（ConsultaTomas.DIASTOLICA）; 
holder.diastolica.setText（d）; 
 
 p = items.getString（ConsultaTomas.PULSO）; 
holder.pulso.setText（p）; 
 
 f = items.getString（ConsultaTomas.FECHA）; 
 SimpleDateFormat sdf = new SimpleDateFormat（ dd / MM / yyyy）; 
 
试试{
holder.fecha.setText（sdf.format（sdf.parse（f）））; 
 
} catch（ParseException e）{
 Log.d（ PARSINGFECHA， Error parcear fecha）; 
} 
 
 
} 
  

其他数据在RecView中正确显示，并且Calendar String都不同，因此这些字符串中没有相同的日期/小时。因此，问题是：

如何使用<$ c $将 Calendar.toString（）转换为日期c> SimpleDateFormat.parse（）？

这是在真实设备上运行应用程序的结果：

解决方案

您需要修改存储日历的方式，调用 getTime（）并根据需要对其进行格式化。例如，

  Calendar cal = Calendar.getInstance（）; 
 DateFormat sdf = new SimpleDateFormat（ MM / dd / yyyy）; 
 System.out.println（sdf.format（cal.getTime（）））; 
  

I'm developing an Android app that uses a database, every time that the user insert a new register the current data and time is save in the db using

Calendar cal = Calendar.getInstance();

So, When I retrieve the data from the db, got a String like this:

java.util.GregorianCalendar[time=1496007575129,areFieldsSet=true,lenient=true,zone=America/Mexico_City,firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2017,MONTH=4,WEEK_OF_YEAR=22,WEEK_OF_MONTH=5,DAY_OF_MONTH=28,DAY_OF_YEAR=148,DAY_OF_WEEK=1,DAY_OF_WEEK_IN_MONTH=4,AM_PM=1,HOUR=4,HOUR_OF_DAY=16,MINUTE=39,SECOND=35,MILLISECOND=129,ZONE_OFFSET=-21600000,DST_OFFSET=3600000]

The problem comes when I try convert that String using SimpleDateFormat.parse to display it in a RecyclerView, I get always the same date: 09/04/2017.

This is the code in my RecViewAdapter.java:

@Override
public void onBindViewHolder(ViewHolder holder,int position){
    items.moveToPosition(position);

    String s,d,p,f;


    s = items.getString(ConsultaTomas.SISTOLICA);
    holder.systolica.setText(s);

    d = items.getString(ConsultaTomas.DIASTOLICA);
    holder.diastolica.setText(d);

    p = items.getString(ConsultaTomas.PULSO);
    holder.pulso.setText(p);

    f = items.getString(ConsultaTomas.FECHA);
    SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");

    try {
        holder.fecha.setText(sdf.format(sdf.parse(f)));

    }catch (ParseException e){
        Log.d("PARSINGFECHA","Error al parcear fecha");
    }


}

The other data is showed correctly in the RecView and the Calendar String are all diferent, so there is not the same date/hour in these strings. So, the question is:

How can I Convert Calendar.toString() into date using SimpleDateFormat.parse()?

This is the result running the app in a real device:

解决方案

You need to modify the way you store the Calendar, call getTime() and format it as desired to begin with. For example,

Calendar cal = Calendar.getInstance();
DateFormat sdf = new SimpleDateFormat("MM/dd/yyyy");
System.out.println(sdf.format(cal.getTime()));

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