DB에서 값가져와서 리스트에 부리기

MainActivity.java

package com.example.diary;

import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CursorAdapter;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //1.버튼 찾아불러오기
        Button btn1 = findViewById(R.id.btnWirteForm);
        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //2.Intent를 이용해서 화면을 전환하자.
                Intent intent = new Intent(getApplicationContext(), WriteActivity.class);
                //3.StratActi호출후 인텐트를 넣어서주면 화면전환이 된다. intent에 값을 실어 보내고 싶다면...
                //3.1.putExtr를 사용해서 담으면 된다.
                intent.putExtra("title", "첫번째 제목");
                intent.putExtra("content","첫번째 내용");
                startActivityForResult(intent, 100);
                //4.받는쪽에서 잘 받는지 확인해보자. writeActivity
            }
        });
        //7.리스트뷰를 불러온다.
        ListView listDiary = findViewById(R.id.listDiary);
        //배열 어댑터
        final String[] cafe = getResources().getStringArray(R.array.cafe);
        ArrayAdapter arrayAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, cafe);
        listDiary.setAdapter(arrayAdapter);
        //커서 어댑터
        DBHelper dbhalper = new DBHelper(this); //DB준비
        SQLiteDatabase db = dbhalper.getReadableDatabase(); //DB오픈
        Cursor cursor = db.rawQuery("select rowid _id, _no, title, content from diary order by _no desc;", null);
        CursorAdapter cursorAdapter = new SimpleCursorAdapter(this,
                                                            android.R.layout.simple_list_item_2,
                                                            cursor, new String[]{"TITLE", "CONTENT"},
                                                            new int[]{android.R.id.text1, android.R.id.text2},
                                                            CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER
                                                        );
        listDiary.setAdapter(cursorAdapter);
        listDiary.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                TextView title = view.findViewById(android.R.id.text1);
                Toast.makeText(getApplicationContext(), title.getText().toString(), Toast.LENGTH_SHORT).show();
            }
        });
    }


    //end of onCreate

    //6.write에서 result가 finish 되면 실행되는 이벤트
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK) {
            String msg = data.getStringExtra("msg");
            Toast.makeText(getApplicationContext(),msg,Toast.LENGTH_LONG).show();
            System.out.println(msg);
        }
    }
}//end of class