日期计算器

Question

这是我从日期选择器中选择日期的代码。

import java.util.Calendar;
import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
public class CurrentDateActivity extends Activity {
/** Called when the activity is first created. */
private EditText mDateDisplay,mDateSelect;
private int mYear,mMonth,mDay;
private int year,month,day;  
Button selectBtn = null;
Calendar c = null;
static final int DATE_DIALOG_ID = 0;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.date_select);
    selectBtn = (Button)findViewById(R.id.BtnSubmit);
    mDateDisplay = (EditText) findViewById(R.id.currentDate);
    mDateSelect = (EditText)findViewById(R.id.dateofBirth);
    // add a click listener to the button
    mDateSelect.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            showDialog(DATE_DIALOG_ID);
        }
    });
    getCurrentDate();//get the current date

    // display the current date 
    mDateDisplay.setText(getString(R.string.strSelectedDate,
            new StringBuilder()
                    // Month is 0 based so add 1
                    .append(mDay).append("/")
                    .append(mMonth + 1).append("/")
                    .append(mYear).append(" "))
                    );
}
private void getCurrentDate(){
     // get the current date
    c = Calendar.getInstance();
    mYear = c.get(Calendar.YEAR);
    mMonth = c.get(Calendar.MONTH);
    mDay = c.get(Calendar.DAY_OF_MONTH);
}
// updates the date in the EditText
private void updateDisplay() {
    mDateSelect.setText(getString(R.string.strSelectedDate,
            new StringBuilder()
            .append(mDay).append("/")
            .append(mMonth + 1).append("/")
            .append(mYear).append(" "))
            );  
}
// the callback received when the user "sets" the date in the dialog
private DatePickerDialog.OnDateSetListener mDateSetListener = new DatePickerDialog.OnDateSetListener() {
     public void onDateSet(DatePicker view, int year,  int monthOfYear, int dayOfMonth) {
        mYear = year;
        mMonth = monthOfYear;
        mDay = dayOfMonth;
        updateDisplay();
     }
};

@Override
protected Dialog onCreateDialog(int id) {
    switch (id) {
    case DATE_DIALOG_ID:
        return new DatePickerDialog(this, mDateSetListener, mYear, mMonth,
                mDay);
    }
    return null;
}   
}

一切都很好，但现在我想获得当前日期和用户在另一个活动中输入的日期，以便计算它们之间的差异。但是我不知道如何故意过这个日期。请帮助

Answer 1

如果您要使用共享的首选项，该怎么办？

    //get access to the shared preferences
    SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
    SharedPreferences.Editor editor = preferences.edit();

    //get the current time
    Date now =new Date();
    //create timestamp from the time the user picked
    @SuppressWarnings("deprecation")
    @Deprecated
    Timestamp timestamp = new Timestamp(mYear, mMonth, mDay, now.getHour, now.getMinute,   0, 0);
    //store the timestamp in your shared preferences
    editor.putString(getResources().getString(R.string.calcDate),  timestamp.toString );
    editor.apply();

     //And then in your next activity, you can pull the value back out like 
     //Pull the long timestamp back out from the shared preferences
     long pickedTs = Long.parseLong(preferences.getString(getResources().getString(R.string.calcDate),   ""));
     //Then create a new Date object using the timestamp
     Date pickedDate = new Date(pickedTs);
     //Then clear that preference for the next time
     editor.putString(getResources().getString(R.string.calcDate),  "");
     editor.apply();

这与我目前在应用程序中使用的系统类似。http://developer.android.com/reference/android/content/SharedPreferences.htmlhttp://docs.oracle.com/javase/7/docs/api/java/sql/Timestamp.html也许有一种更性感的方法可以做到这一点，但这只是我的建议。希望它能帮助