目前所寫的程式

package com.example.time2;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.webkit.CookieManager;
import android.webkit.WebView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Spinner;
import android.widget.TextView;

import java.text.SimpleDateFormat;
import java.util.Calendar;

public class MainActivity extends AppCompatActivity {
    Spinner ES;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Calendar c = Calendar.getInstance();
        Calendar c2 = Calendar.getInstance();
        Calendar c3 = Calendar.getInstance();
        Calendar c4 =Calendar.getInstance();
        Calendar c5 =Calendar.getInstance();
        SimpleDateFormat sd = new SimpleDateFormat("yyyy-MM-dd");
        SimpleDateFormat sl = new SimpleDateFormat("u");
        c2.add(Calendar.DAY_OF_MONTH,1);//加1天
        c3.add(Calendar.DAY_OF_MONTH,2);
        c4.add(Calendar.DAY_OF_MONTH,3);
        c5.add(Calendar.DAY_OF_MONTH,4);

        String dat = sd.format(c.getTime());//當天
        String dat2 = sd.format(c2.getTime());//明天
        String dat3 = sd.format(c3.getTime());//後天
        String dat4 = sd.format(c4.getTime());//三天後
        String dat5 = sd.format(c5.getTime());//四天後
        String datt = sl.format(c.getTime());//當天星期

        ES = (Spinner)findViewById(R.id.es);

        String[] Weekday ={dat,dat2,dat3};
        String[] Weekday2 ={dat,dat2,dat5};
        String[] Weekday3 ={dat,dat4,dat5};

        TextView TV =(TextView)findViewById(R.id.da);
        TV.setText(datt);
        int intV = Integer.valueOf(datt);//字串datt轉換成整數
        switch(intV){
        case '7'://當天周日
           ArrayAdapter<String> lunchList2 = new ArrayAdapter<>
              (MainActivity.this,
                        android.R.layout.simple_spinner_dropdown_item,
                        Weekday2);ES.setAdapter(lunchList2);
                break;

        case '5'://當天周五
           ArrayAdapter<String> lunchList3 = new ArrayAdapter<>
                (MainActivity.this,
                        android.R.layout.simple_spinner_dropdown_item,
                        Weekday3);ES.setAdapter(lunchList3);
                break;
        default:
           ArrayAdapter<String> lunchList = new ArrayAdapter<>
                (MainActivity.this,
                        android.R.layout.simple_spinner_dropdown_item,
                        Weekday);ES.setAdapter(lunchList);
                        //其餘日子
                break;
        }

設了三種日期選項組合 帶入下拉式選單ES
抓取當天日期改為整數用Switch判斷當天星期來決定該再下拉式選單丟入哪一個日期選項
測試上皆只會選擇default的結果

若把case 改成當天的星期也不會做修改
ex:若當天為周日
case '7':
ArrayAdapter lunchList2 = new ArrayAdapter<>
(MainActivity.this,android.R.layout.simple_spinner_dropdown_item
,Weekday2);ES.setAdapter(lunchList2);
break;

不知道是不是switch判斷的方式用的不對
想請問寫法是不是錯了.....