我如何計算預定義的日期時間和最近的日期時間之間的差異

Question

那麼我想定義一個日期，並以秒爲單位查看與最近日期的差異。 下面是代碼我做活動的onCreate方法內：

txtNowTime = (TextView)findViewById(R.id.textViewNow); 

    SimpleDateFormat formata = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss"); 

    String currentDateandTime = formata.format(new Date()); 

    @SuppressWarnings("deprecation") 
    Date oldd = new Date("07/18/2014 11:12:13"); 
    String olddt_frmt = formata.format(oldd); 

    long diff =0; 
    try { 
      Date d_recent = formata.parse("currentDateandTime"); 

      diff = d_recent.getTime() - oldd.getTime(); 


     } catch (ParseException ex) { 
      ex.printStackTrace();   } 

    txtNowTime.setText(String.valueOf(diff)); 

但它沒有顯示任何結果。 :-(

Answer 1

更改此
Date d_recent = formata.parse("currentDateandTime");到Date d_recent = formata.parse(currentDateandTime);

Answer 2

請使用喬達時間找到答案

SimpleDateFormat formata = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss", Locale.getDefault()); 
String currentDateandTime = formata.format(new Date()); 
long diff = 0; 
try { 
Date d_recent = formata.parse(currentDateandTime); 
Date olddt_frmt = formata.parse("07/18/2014 11:12:13"); 
diff = d_recent.getTime() - olddt_frmt.getTime(); 
} catch (ParseException ex) { 
    ex.printStackTrace(); 
} 

Answer 3

見this similar question，或者在Java中8老使用新java.time包java.util.Date和.Calendar類是非常麻煩的，應該避免。

Joda-Time

DateTime then = DateTime.now(); 
//… 
DateTime now = DateTime.now(); 
Seconds seconds = Seconds.secondsBetween(now, then); 
int secondsElapsed = seconds.getSeconds();