Android::리스트뷰사용해서 메모장만들기

● 완성한 뷰

[O] 새로운 메모 추가

[O] 메모 클릭시 편집

[O] 메모 롱클릭시 삭제 가능

[X] 검색

● 작성한 코드

 

MainActivity

package com.example.memoapplication;

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

import android.app.Dialog;
import android.content.DialogInterface;
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.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;

public class MainActivity extends AppCompatActivity {

    ArrayList<Memo> memoArrayList = new ArrayList<>();

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

        ImageButton backBtn = findViewById(R.id.main_btn_back);
        ImageButton searchBtn = findViewById(R.id.main_btn_search);
        ImageButton newBtn = findViewById(R.id.main_btn_add_text);
        TextView memoCount = findViewById(R.id.main_tv_count);


        //DBHelper 객체 생성
        String dbName = "Memo.db";
        int dbVersion =1;
        final DBHelper dbHelper;

        // memoArrayList 에 데이터 값을 넣어서 가져와주기
        dbHelper = new DBHelper(this,dbName,null,dbVersion);
        final SQLiteDatabase db = dbHelper.getReadableDatabase();
        final String sql = "SELECT * FROM Memo;";
        Cursor cursor = db.rawQuery(sql,null);
        memoCount.setText(String.valueOf(cursor.getCount()));   // 메모장 갯수 캐스팅
        try{
            if(cursor.getCount()>0)
            {
                while(cursor.moveToNext())
                {
                    // 데이터 베이스에 있는 값들의 string 값을 Memo 클래스 생성자에 담아서 만들어 준다.
                    // 더미 데이터가 아닌, 데이터 베이스에 있는 값들을 넣어주는 작업.

                    Memo m = new Memo(cursor.getString(1),cursor.getString(2));
                    memoArrayList.add(m);
                }
            }
        }finally {
            cursor.close();
        }


        // Dummies
        // memoArrayList.add(new Memo("Today's Diary", "a;laj;alksjdg;lasjdgljewjf;aklvmjdlfjl;aksnvldfddasdfasdfadfasdfasdfadsfaa"));
        // memoArrayList.add(new Memo("TO DO LIST", "aasvadsgmjdlfjl;aksnvldfddasdfasdfadfasdfasdfadsfaa"));
        // memoArrayList.add(new Memo("Homework", "aasdgasdgdgljewjf;aklvmjdlfjl;aksnvldfddasdfasdfadfasdfasdfadsfaa"));

        // 리스트 뷰 연결
        final ListView listView = findViewById(R.id.main_lv_memo_list);
        MemoAdapter memoAdapter = new MemoAdapter(memoArrayList,this);
        listView.setAdapter(memoAdapter);


        // 리스트 뷰 내 아이템 클릭시 → Edit 액티비티로 넘어간다.
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                // 리스트 뷰를 누를 때 EditActivity 로 넘어가야한다.
                // 이때 클릭된 값에 해당하는 title 과, contents 를 그대로 넘겨 줘야 한다.
                int check_position = listView.getCheckedItemPosition(); //리스트 뷰의 포지션을 가져옴.
                Memo vo =(Memo)parent.getAdapter().getItem(position);  //리스트 뷰의 포지션 가져옴.
                String t_title = vo.getTitle();
                String c_contents =vo.getContents();

                Intent intent = new Intent(MainActivity.this,EditActivity.class);
                intent.putExtra("title",t_title);
                intent.putExtra("contents",c_contents);
                intent.putExtra("position",position);

                startActivity(intent);
                finish();
            }


        });

        // 리스트 뷰 내 아이템 롱 클릭시 → AlertDialog 로 "삭제" 가 뜨고 "삭제"를 누를시에 그 아이템 삭제
        listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
                Memo vo =(Memo)parent.getAdapter().getItem(position);  //리스트 뷰의 포지션 가져옴.
                final String t_title = vo.getTitle();
                String c_contents =vo.getContents();
                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

                builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                       // 메모 삭제 작업
                        String sql0 ="DELETE FROM Memo WHERE title = '"+ t_title +"';";
                        db.execSQL(sql0);

                        Intent intent = new Intent(MainActivity.this, MainActivity.class);
                        finish();
                        startActivity(intent);

                    }
                });
                builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                });
                builder.setMessage("Do you want to delete this memo?");
                builder.setTitle("Delete Notification");
                builder.show();
                return true;
            }
        });


        // 뒤로 가기 버튼 누를 시에 처리.
        backBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

                builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // 이 액티비티 종료
                        finish();
                    }
                });
                builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                });
                builder.setMessage("Do you want to quit this app?");
                builder.setTitle("Exit Notification");
                builder.show();
            }
        });

        // 찾기 버튼 누를 시에 처리
        searchBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // alertDialog 가 아니라 dialog 를 사용해볼건데, 그러려먼 xml 파일이 따로 필요하다.
                Dialog dialog = new Dialog(MainActivity.this);
                dialog.setContentView(R.layout.search_dialog);
                dialog.show();

                ImageButton dialog_search_btn = dialog.findViewById(R.id.search_dialog_btn);
                final EditText dialog_search_et = dialog.findViewById(R.id.search_dialog_et_title);

                dialog_search_btn.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        String title = dialog_search_et.getText().toString();
                        String sql0 ="SELECT * FROM Memo WHERE title = '"+ title +"';";
                        Cursor cs = db.rawQuery(sql0,null);

                        String get_title = cs.getString(1);
                        String get_contents = cs.getString(2);

                        Intent intent = new Intent(MainActivity.this,EditActivity.class);
                        intent.putExtra("title",get_title);
                        intent.putExtra("contents",get_contents);

                        startActivity(intent);
                        finish();

                    }
                });

            }
        });

        // New 버튼 누를 시에 처리 → detail Activity 로 보내주고 거기서 데이터 추가 하게끔 할 것이다.
        newBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this,DetailActivity.class);
                finish();   //자꾸 쌓이는 것 방지.
                startActivity(intent);
            }
        });

    }
}

 

 

 

 

 

EditActivity

package com.example.memoapplication;

import android.content.DialogInterface;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageButton;

import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

public class EditActivity extends AppCompatActivity {

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_detail);
        getSupportActionBar().hide();

        //DBHelper 객체 생성
        String dbName = "Memo.db";
        int dbVersion =1;
        final DBHelper dbHelper;
        dbHelper = new DBHelper(this,dbName,null,dbVersion);

        Intent intent = getIntent();
        final String got_title = intent.getStringExtra("title");
        String got_contents = intent.getStringExtra("contents");
        int got_positon = intent.getIntExtra("position",0);

        final EditText title = findViewById(R.id.detail_et_title);
        final EditText contents = findViewById(R.id.detail_et_contents);
        ImageButton save_btn = findViewById(R.id.detail_ib_save);
        ImageButton cancel_btn = findViewById(R.id.detail_ib_cancel);
        ImageButton back_btn = findViewById(R.id.detail_ib_back);

        title.setText(got_title);
        contents.setText(got_contents);



        save_btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 이 데이터 값을 바꿔줘야 한다.
                // 받아온 title 로  조회해서 바꾼다.
                SQLiteDatabase db = dbHelper.getWritableDatabase();
                String final_title = title.getText().toString();
                String final_contents = contents.getText().toString();
                String sql = "UPDATE Memo SET title='"+final_title+"',contents='"+final_contents+"'WHERE title='"+got_title+"';";
                db.execSQL(sql);

                AlertDialog.Builder builder = new AlertDialog.Builder(EditActivity.this);

                builder.setNegativeButton("Ok", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                });
                builder.setMessage("The note has been saved well :)");
                builder.setTitle("Notification");
                builder.show();
            }
        });

        cancel_btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 메인으로 다시
                Intent intent = new Intent(EditActivity.this, MainActivity.class);
                finish();
                startActivity(intent);

            }
        });

        back_btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 메인으로 다시
                Intent intent = new Intent(EditActivity.this, MainActivity.class);
                finish();
                startActivity(intent);
            }
        });

    }

    @Override
    protected void onPause() {
        super.onPause();
    }
}

 

 

 

 

 

DetailActivity

package com.example.memoapplication;

import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

import android.content.DialogInterface;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.Toast;

public class DetailActivity extends AppCompatActivity {

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

        //DBHelper 객체 생성
        String dbName = "Memo.db";
        int dbVersion =1;
        final DBHelper dbHelper;
        dbHelper = new DBHelper(this,dbName,null,dbVersion);


        final EditText title = findViewById(R.id.detail_et_title);
        final EditText contents = findViewById(R.id.detail_et_contents);
        ImageButton save_btn = findViewById(R.id.detail_ib_save);
        ImageButton cancel_btn = findViewById(R.id.detail_ib_cancel);

        // final String titleStr = title.getText().toString();
        // final String contentsStr =contents.getText().toString();

        // save_btn 을 누르면 데이터 베이스에 들어간다.
        save_btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String titleStr = title.getText().toString();
                String contentsStr =contents.getText().toString();

                SQLiteDatabase db = dbHelper.getWritableDatabase();
                String sql = String.format("INSERT INTO Memo VALUES(NULL,'%s','%s');", titleStr, contentsStr);
                db.execSQL(sql);
                // 저장 된다면 toast 메세지 같은 거 띄우기
                Toast.makeText(getApplicationContext(),"save well.",Toast.LENGTH_SHORT).show();
            }
        });

        // cancel_btn 을 누르면 이 액티비티 끝내고 main 화면 돌아간다.
        cancel_btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(DetailActivity.this,MainActivity.class);
                startActivity(intent);
                finish();
            }
        });
    }

    @Override
    // 뒤로가기 버튼을 누르면, Alert 뜨고 이 액티비티 없애고 Main 으로 돌아가게.
    public void onBackPressed() {
        super.onBackPressed();
        AlertDialog.Builder builder = new AlertDialog.Builder(DetailActivity.this);

        builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                Intent intent = new Intent(DetailActivity.this,MainActivity.class);
                startActivity(intent);
                finish();
            }
        });
        builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
            }
        });
        builder.setMessage("back to the previous screen?");
        builder.setTitle("Notification");
        builder.show();
    }

    @Override
    protected void onPause() {
        // 작성 중인 메모 contents 저장 해 놓아야 한다.
        super.onPause();
    }
}

 

 

 

 

 

DBHelper

package com.example.memoapplication;

import android.content.Context;
import android.database.DatabaseErrorHandler;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

public class DBHelper extends SQLiteOpenHelper {

    public DBHelper(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) {
        super(context, name, factory, version);
    }

    // DB 처음 만들 때 한번만 호출 : 테이블 생성
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE Memo (id INTEGER PRIMARY KEY AUTOINCREMENT," +
                "title String PRIMARY KEY, contents String);");
    }

    // 버전 업데이트 되면 DB를 다시 만든다.
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS Memo");
        onCreate(db);
    }
}

 

 

Memo

package com.example.memoapplication;

public class Memo {
    String title;
    String contents;

    public Memo(String title, String contents) {
        this.title = title;
        this.contents = contents;
    }

    public String getContents() {
        return contents;
    }

    public String getTitle() {
        return title;
    }
}

 

 

 

 

 

MemoAdapter

package com.example.memoapplication;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

import androidx.constraintlayout.widget.ConstraintLayout;

import java.util.ArrayList;

public class MemoAdapter extends BaseAdapter {
    ArrayList<Memo> memoArrayList = new ArrayList<>();
    Context mContext;

    public MemoAdapter(ArrayList<Memo> memoArrayList, Context mContext) {
        this.memoArrayList = memoArrayList;
        this.mContext = mContext;
    }

    @Override
    public int getCount() {
        return memoArrayList.size();
    }

    @Override
    public Object getItem(int position) {
        return memoArrayList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View itemView = inflater.inflate(R.layout.item_memo,parent,false);

        TextView tvTitle = itemView.findViewById(R.id.memo_tv_title);
        TextView tvContents = itemView.findViewById(R.id.memo_tv_contents);

        tvTitle.setText(memoArrayList.get(position).title);
        tvContents.setText(memoArrayList.get(position).contents);

        return itemView;
    }
}

 

● 참고한 블로그

object클래스의 getClass 메소드란? 

zzdd1558.tistory.com/57

★ Android Cursor를 이용한 DB 데이터 사용하기

arabiannight.tistory.com/entry/368

토스트 메세지 띄우기

m.blog.naver.com/PostView.nhn?blogId=seungbin0619&logNo=221221022763&proxyReferer=https:%2F%2Fwww.google.com%2F

★ 모든 Activity에서 사용하는 데이터 저장 -DB 사용법

m.blog.naver.com/PostView.nhn?blogId=hg1286&logNo=220539030447&proxyReferer=https:%2F%2Fwww.google.com%2F
리스트 항목 클릭

kitesoft.tistory.com/67

롱클릭

bitsoul.tistory.com/11