java - 如何比较两个java sql日期，一个在列表中，另一个刚刚输入

Question

我已经尝试过这里发布的许多问题。我仍然没有找到解决问题的方法，

我想比较用户输入的日期，在我的 android 应用程序中，我将日期存储在 ArrayList 中。

我不想将克隆存储到已保存的日期，所以我必须检查一下。我正在使用 Java sql 日期来避免时间部分。

static List<DatefromTo> myList;
myList = new ArrayList<Dateclassobject>();
i =myList.size();

for(int j = 1; j <= myList.size(); j ++){
    int results2 = myList.get(i).datefrom.compareTo(myList.get(j).datefrom);
    if(results2 > 0 ){
        Toast.makeText(getApplicationContext(),"First Date is after second",Toast.LENGTH_LONG).show();
    }else if(results2 < 0){
        Toast.makeText(getApplicationContext(), "Wrong", Toast.LENGTH_LONG).show();
    }else if(results2 == 0){
        Toast.makeText(getApplicationContext(),String.valueOf(myList.get(i).datefrom) + "------" + String.valueOf(myList.get(j).datefrom),Toast.LENGTH_LONG).show();
    }else{
        Toast.makeText(getApplicationContext(), "Hi", Toast.LENGTH_LONG).show();
    }
}

datefrom和dateto存储在Dateclassobject的everyobject中

所以我想要实现的是，如果用户输入了从 datefrom 到 dateto 的时间段，并且该时间段已经存在于另一个时间段或者是存在于列表本身中，它不会再次输入。那么我怎样才能最好地检查呢？

另外我想知道为什么getYear(), 或者getDate() 给出错误的答案？

---

这是 DateClassObject 代码:

import java.util.Date;

public class DateClassObject {

    public static Date datefrom;
    public static Date dateto;

    public static Date difference;

    public DateClassObject() {
        super();
    }

    @SuppressWarnings("static-access")
    public DateClassObject(Date datefrom, Date dateto) {
        super();

        this.datefrom = datefrom;
        this.dateto = dateto;
    }
}

下面是这个类 Dateadd 的全部代码，我在这里做所有事情

import java.sql.Date;
import java.util.ArrayList;
import java.util.Calendar;

//import java.util.Date;

import java.util.List;


import android.app.Activity;
import android.app.DatePickerDialog;
import android.graphics.Color;
import android.os.Bundle;

import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;

import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.TableLayout;
import android.widget.TableRow;

import android.widget.TextView;
import android.widget.Toast;

public class DateAdd extends Activity {
    private Button buttonsubmit;

    DatePickerDialog dpdfrom, dpdto;

    Date dtFrom, dtTo;

    long milisto, milisfrom, days, diff;

    int i;

    Button delete;
    TableLayout stk;
    TextView tvadd, tvadd2, tvadd3, tvfrompick, tvtopick, t1v;

    String abc;
    DatefromTo datefromto, dtFT;

    int listSize;

    int mYearfrom, mMonthfrom, mDayfrom, mYearto, mMonthto, mDayto;

    static List<DateClassObject> myList;

    Calendar from;  // get the from date from user and store here
    Calendar to; // get the to date from user and store here

    EditText et;
    String datetoday, difference, string1, string2;

    Long bringto, bringfrom, between;
    boolean wrong;
    boolean entryremover;

    // boolean yrfm , mnfm , dyfm , yrto , mnto , dyto;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.dateadd);

         from = Calendar.getInstance();

         to= Calendar.getInstance();

        final Calendar c = Calendar.getInstance();
        mYearfrom = c.get(Calendar.YEAR);
        mMonthfrom = c.get(Calendar.MONTH);
        mDayfrom = c.get(Calendar.DAY_OF_MONTH);

        mYearto = c.get(Calendar.YEAR);
        mMonthto = c.get(Calendar.MONTH);
        mDayto = c.get(Calendar.DAY_OF_MONTH);

        buttonsubmit = (Button) findViewById(R.id.buttonsubmit);

        et = (EditText) findViewById(R.id.et);

        // tvspecial = (TextView) findViewById(R.id.tvspecial);

        tvfrompick = (TextView) findViewById(R.id.tvfrompick);
        tvtopick = (TextView) findViewById(R.id.tvtopick);

        myList = new ArrayList<DateClassObject>();

        i = (myList.size()-1);

        init();

        if (entryremover == true) {

            delete.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    myList.remove(dtFT);

                }
            });
        }

        buttonsubmit.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                dtFT = new DatefromTo(from,to);





                if(from.before(to)){

                    myList.add(dtFT);

                    AddEntry();
                }

                for(int j = 0; j < myList.size(); j ++){ //Note. you've written, 
                    //for(int j = 1; j <= myList.size(); j ++) , ArrayList index start from 0. you'll miss the first element. I hope it helps you in the future

                    Calendar dateFrom = myList.get(j).dateFrom;
                    Calendar dateTo = myList.get(j).dateTo;

                    if(isSameDay(from, dateFrom) && isSameDay(to, dateTo)){ // checking same period allready exists

                        Toast.makeText(getApplicationContext(),
                                "Already exist",
                                 Toast.LENGTH_LONG).show();
                    }
                    else{
                        // if it does not exists, I assume that you want to add it your arrayList
                        myList.add(new DatefromTo(from, to));
                    }

                    t1v.setText((myList.get(j).dateFrom
                            + "\n" + myList.get(j).dateTo + "\n"));

                }


                tvfrompick.setText("");

                tvtopick.setText("");









            }
        });



        tvfrompick.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                dpdfrom.show();

            }
        });

        tvtopick.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                dpdto.show();

            }
        });

        dpdfrom = new DatePickerDialog(this,
                new DatePickerDialog.OnDateSetListener() {

                    @Override
                    public void onDateSet(DatePicker view, int year,
                            int monthOfYear, int dayOfMonth) {

                        tvfrompick.setText(dayOfMonth + "-" + monthOfYear + 1
                                + "-" + year);

                        mDayfrom = dayOfMonth;
                        mMonthfrom = (monthOfYear);
                        mYearfrom = year;

                    //  dtFrom = new Date(mYearfrom - 1900, mMonthfrom,mDayfrom);


                        from.set(mYearfrom, mMonthfrom,
                                mDayfrom);
                    }
                }, mYearfrom, mMonthfrom, mDayfrom);

        dpdto = new DatePickerDialog(this,
                new DatePickerDialog.OnDateSetListener() {

                    @SuppressWarnings({ "deprecation", "deprecation" })
                    @Override
                    public void onDateSet(DatePicker view, int year,
                            int monthOfYear, int dayOfMonth) {

                        tvtopick.setText(dayOfMonth + "-" + monthOfYear + 1
                                + "-" + year);

                        mDayto = dayOfMonth;
                        mMonthto = (monthOfYear);
                        mYearto = year;


                    //  dtTo = new Date((mYearto - 1900), mMonthto, mDayto);
                        to.set( mYearto, mMonthto,  mDayto);

                    }
                }, mYearto, mMonthto, mDayto);


    }

    public boolean isSameDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("null");
        }
        return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
    }


    public void init() {
        stk = (TableLayout) findViewById(R.id.table_main);
        TableRow tbrow0 = new TableRow(this);
        TextView tv0 = new TextView(this);
        tv0.setText("From");
        tv0.setTextColor(Color.WHITE);
        tv0.setPadding(20, 10, 20, 10);
        tbrow0.addView(tv0);

        TextView tv1 = new TextView(this);
        tv1.setText(" To " + myList.size());
        tv1.setTextColor(Color.WHITE);
        tv1.setPadding(20, 10, 20, 10);
        tv1.getPaddingLeft();
        tbrow0.addView(tv1);
        // Button tv2 = new Button(this);
        // tv2.setText("Delete ");
        // tv2.getPaddingLeft();
        // //tv2.setTextColor(Color.WHITE);
        // tbrow0.addView(tv2);

        stk.addView(tbrow0);
    }

    public void AddEntry() {
        entryremover = true;
        TableRow tbrow = new TableRow(this);
        t1v = new TextView(this);
        // t1v.setText("From" + i);
        myList.get(myList.size() - 1);
        t1v.setTextColor(Color.WHITE);
        t1v.setGravity(Gravity.CENTER);
        t1v.setPadding(20, 10, 20, 10);
        tbrow.addView(t1v);

        delete = new Button(this);
        delete.setText("Delete");
        delete.setTextColor(Color.WHITE);
        delete.setGravity(Gravity.CENTER);
        delete.setPadding(20, 10, 20, 10);

        tbrow.addView(delete);

        stk.addView(tbrow);
    }

    public void removeEntry() {

    }
}

Answer 1

使用日历而不是日期。 (对我来说更容易，因为我在我正在从事的项目中拥有你正在寻找的大部分内容)

List<DateClassObject> myList = new ArrayList<>();

Calendar from =  // get the from date from user and store here
Calendar to = // get the to date from user and store here

//to check 'from' is after 'to'

if(from.after(to)){
    // Do your operation
}

for(int j = 0; j < myList.size(); j ++){ //Note. you've written, for(int j = 1; j <= myList.size(); j ++) , ArrayList index start from 0. you'll miss the first element. I hope it helps you in the future

    Calendar dateFrom = myList.get(j).dateFrom;
    Calendar dateTo = myList.get(j).dateTo;

    if(isSameDay(from, dateFrom) && isSameDay(to, dateTo)){ // checking same period allready exists
        // if it exists Do operation
    }
    else{
        // if it does not exists, I assume, you want to add DateClassObject to your arrayList
        myList.add(new DateClassObject(from, to));
    }
}

public boolean isSameDay(Calendar cal1, Calendar cal2) {
    if (cal1 == null || cal2 == null) {
        throw new IllegalArgumentException("The dates must not be null");
    }
        return (cal1.get(Calendar.MONTH) == cal2.get(Calendar.MONTH) &&
            cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
            cal1.get(Calendar.DAY_OF_MONTH) == cal2.get(Calendar.DAY_OF_MONTH));
}

public class DateClassObject {

    public Calendar dateFrom;
    public Calendar dateTo;

    public Date difference;

    public DateClassObject(Calendar dateFrom, Calendar dateTo) {
        this.dateFrom = dateFrom;
        this.dateTo = dateTo;
    }
}

我想这就是您要找的。问候

编辑:

像这样将日期选择器中选择的日期存储到日历实例中。

int day = datePicker.getDayOfMonth();
int month = datePicker.getMonth();
int year =  datePicker.getYear();

Calendar from = Calendar.getInstance();
from.set(year, month, day);

编辑:

好的，我对您的按钮点击做了一些更改，在 if 语句中添加 for 循环。如果我假设正确，那么只有当 fromDate 不在 toDate 之前并且它不是重复条目时，你才想添加到 arraylist

buttonsubmit.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View v) {

        if(from.before(to)){

            boolean alreadyExists = false;
            for(int j = 0; j < myList.size(); j ++){ 

                Calendar dateFrom = myList.get(j).dateFrom;
                Calendar dateTo = myList.get(j).dateTo;

                if(isSameDay(from, dateFrom) && isSameDay(to, dateTo)){ // checking same period allready exists
                    alreadyExists = true;
                    break;
                }
            }
            if (alreadyExists){
                Toast.makeText(getApplicationContext(),
                            "Already exist",
                            Toast.LENGTH_LONG).show();
            }
            else{
                myList.add(new DateClassObject(from, to));
            }
        }
        tvfrompick.setText("");
        tvtopick.setText("");
    }
});

至于您在代码 myList.remove(dtFT); 中编写的删除按钮。 remove 方法将数组列表中的位置作为参数(整数值)。myList.remove(2) 从列表中删除第二个元素。所以找出一些方法来获取要删除的元素的位置。