android - 如何计算时差并以00:00格式显示结果？

如何计算时差并以00:00格式显示结果。
我找不到方法，如何将字符串数据发送到日期以及如何以EditText 00:00格式显示结果。
我自己尝试过，但是它显示找不到源的错误。
下面是代码。

public class TimeCalculate extends Activity {

private String mBlock = null;
private String mBlockoff = null;
private String mBlockon = null;

     Date date1,date2;
     EditText block;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    EditText blockoff = (EditText) findViewById(R.id.blockoff);
    mBlockoff = blockoff.getText().toString();

    EditText blockon = (EditText) findViewById(R.id.blockon);
    mBlockon = blockon.getText().toString();
    block = (EditText) findViewById(R.id.block);
    mBlock = getDifference(date1, date2);

         date1 = new Date(mBlockoff);
    date2 = new Date(mBlockon);

              blockon.addTextChangedListener(new TextWatcher() {
        public void afterTextChanged(Editable s) {
            block = (EditText) findViewById(R.id.block);
            mBlock = getDifference(date1, date2);
            block.setText(mBlock);
        }

}

public static String getDifference(Date startTime, Date endTime) {
    String timeDiff;
    if (startTime == null)
        return "[corrupted]";
    Calendar startDateTime = Calendar.getInstance();
    startDateTime.setTime(startTime);
    Calendar endDateTime = Calendar.getInstance();
    endDateTime.setTime(endTime);
    long milliseconds1 = startDateTime.getTimeInMillis();
    long milliseconds2 = endDateTime.getTimeInMillis();
    long diff = milliseconds2 - milliseconds1;
    long hours = diff / (60 * 60 * 1000);
    long minutes = diff / (60 * 1000);
    minutes = minutes - 60 * hours;
    long seconds = diff / (1000);

    timeDiff = hours + ":" + minutes;
    return timeDiff;
}
}

我使用SampleDateFormat修改的代码

SimpleDateFormat simpleDateFormat = new SimpleDateFormat("hh:mm");

    try {
        date1 = simpleDateFormat.parse(mBlockoff);
    } catch (ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    try {
        date2 = simpleDateFormat.parse(mBlockon);
    } catch (ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

然后我把方法叫做如下

blockon.addTextChangedListener(new TextWatcher() {
        public void afterTextChanged(Editable s) {
            mBlock = getDifference(date1, date2);
            block.setText(mBlock);
        }

最佳答案

方法之一可以是：
计算以毫秒为单位的差异，将其转换为秒，然后使用DateUtils.elapsedTime(int sec)以hh：mm格式设置经过时间的格式。

请参阅DateUtils，Formatter的文档。

编辑：示例代码：此函数将以hh:mm:ss格式返回时间

String getDifference(long now, long then){
        if(now > then)
            return DateUtils.formatElapsedTime((now - then)/1000L);
        else
            return "error";
    }