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

问题描述

我正在开发一个使用数据库的 Android 应用程序，每次用户插入新的寄存器时，当前数据和时间都会保存在数据库中

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();

所以，当我从数据库中检索数据时，得到一个这样的字符串:

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]

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]

当我尝试使用 SimpleDateFormat.parse 转换该字符串以在 RecyclerView 中显示它时，问题出现了，我总是得到相同的日期:09/04/2017.

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.

这是我的 RecViewAdapter.java 中的代码:

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");
    }


}

其他数据在 RecView 中正确显示并且日历字符串都不同，因此这些字符串中的日期/小时不一样.所以，问题是:

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:

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

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

这是在真实设备上运行应用程序的结果:

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

推荐答案

需要修改Calendar的存储方式，调用getTime()，格式化为想要开始.例如，

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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