roomdb

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:orientation="vertical">


    <Space
        android:layout_width="match_parent"
        android:layout_height="20dp" />

    <TextView
        android:id="@+id/roomtext1"
        android:layout_width="300dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:gravity="center"
        android:textSize="25dp"
        android:text="日付" />

    <TextView
        android:id="@+id/roomtext2"
        android:layout_width="300dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:gravity="center"
        android:textSize="25dp"
        android:text="2022:12:19:18:59:39" />

    <TextView
        android:id="@+id/roomtextmax"
        android:layout_width="300dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:gravity="center"
        android:textSize="25dp"
        android:text="データ保存数:0" />

    <TextView
        android:id="@+id/roomtextdebug"
        android:layout_width="300dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:gravity="center"
        android:textSize="25dp"
        android:text="" />

    <Space
        android:layout_width="match_parent"
        android:layout_height="20dp" />

    <LinearLayout
        android:layout_width="300dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:orientation="horizontal">

        <Button
            android:id="@+id/roombtnleft"
            android:layout_width="100dp"
            android:layout_height="50dp"
            android:text="←" />

        <TextView
            android:id="@+id/roomtext3"
            android:layout_width="100dp"
            android:layout_height="50dp"
            android:gravity="center"
            android:text="1/1" />

        <Button
            android:id="@+id/roombtnright"
            android:layout_width="100dp"
            android:layout_height="50dp"
            android:text="→" />
    </LinearLayout>

    <Button
        android:id="@+id/roombtnadd"
        android:layout_width="300dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:text="登録" />

    <Button
        android:id="@+id/roombtndelete"
        android:layout_width="300dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:text="削除" />

    <Button
        android:id="@+id/roombtnalldelete"
        android:layout_width="300dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:text="全削除" />
</LinearLayout>

MainActivity.java

package uta.utauta.roomdb;

import androidx.appcompat.app.AppCompatActivity;
import androidx.room.Room;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import java.util.Calendar;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private TextView roomtext1;
    private TextView roomtext2;
    private TextView roomtext3;
    private TextView roomtextdebug;
    private TextView roomtextmax;

    private Button roombtnleft;
    private Button roombtnright;
    private Button roombtnadd;
    private Button roombtndelete;
    private Button roombtnalldelete;

    private String monthtext;
    private String daytext;
    private String hourtext;
    private String minutetext;
    private String secondtext;

    private int listpage = 1;
    private int listmax = 0;
    private int listid = 0;

    private List<RoomEntity> list;

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

        roomtext1 = findViewById(R.id.roomtext1);
        roomtext2 = findViewById(R.id.roomtext2);
        roomtext3 = findViewById(R.id.roomtext3);
        roomtextdebug = findViewById(R.id.roomtextdebug);
        roomtextmax = findViewById(R.id.roomtextmax);

        roombtnleft = findViewById(R.id.roombtnleft);
        roombtnleft.setOnClickListener(this);
        roombtnright = findViewById(R.id.roombtnright);
        roombtnright.setOnClickListener(this);
        roombtnadd = findViewById(R.id.roombtnadd);
        roombtnadd.setOnClickListener(this);
        roombtndelete = findViewById(R.id.roombtndelete);
        roombtndelete.setOnClickListener(this);
        roombtnalldelete = findViewById(R.id.roombtnalldelete);
        roombtnalldelete.setOnClickListener(this);

        loaddb();
    }

    private void loaddb() {
        ExecutorService executor = Executors.newSingleThreadExecutor();
        executor.execute(new Runnable() {
            @Override
            public void run() {
                RoomTimeDatabase db = Room.databaseBuilder(getApplicationContext(),
                        RoomTimeDatabase.class, "roomtime").build();

                RoomTimeDao dao = db.roomtimedao();

                list = dao.getall();
                listmax = list.size();

                if(list.size() > 0) {
                    RoomEntity entity = list.get(listpage - 1);
                    int year = entity.getyear();
                    int month = entity.getmonth();
                    if(month < 10) {
                        monthtext = "0" + month;
                    } else {
                        monthtext = "" + month;
                    }
                    int day = entity.getday();
                    if(day < 10) {
                        daytext = "0" + day;
                    } else {
                        daytext = "" + day;
                    }
                    int hour = entity.gethour();
                    if(hour < 10) {
                        hourtext = "0" + hour;
                    } else {
                        hourtext = "" + hour;
                    }
                    int minute = entity.getminute();
                    if(minute < 10) {
                        minutetext = "0" + minute;
                    } else {
                        minutetext = "" + minute;
                    }
                    int second = entity.getsecond();
                    if(second < 10) {
                        secondtext = "0" + second;
                    } else {
                        secondtext = "" + second;
                    }
                    listid = entity.getId();

                    roomtext2.setText(year + ":" + monthtext + ":" + daytext + ":" + hourtext + ":" + minutetext + ":" + secondtext);
                    roomtext3.setText(listpage + "/" + listmax);
                    roomtextmax.setText("データ保存数:" + listmax);
                } else {
                    roomtext3.setText("データ無し");
                    roomtext2.setText("");
                    roomtextmax.setText("データ保存数:0");
                    roomtextdebug.setText("");
                }
            }
        });
    }

    private void writedb() {
        ExecutorService executor = Executors.newSingleThreadExecutor();
        executor.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    Calendar c = Calendar.getInstance();

                    int year = c.get(Calendar.YEAR);
                    int month = c.get(Calendar.MONTH) + 1;
                    int day = c.get(Calendar.DATE);
                    int hour = c.get(Calendar.HOUR);
                    int minute = c.get(Calendar.MINUTE);
                    int second = c.get(Calendar.SECOND);

                    RoomTimeDatabase db = Room.databaseBuilder(getApplicationContext(),
                            RoomTimeDatabase.class, "roomtime").build();

                    RoomTimeDao dao = db.roomtimedao();

                    RoomEntity entity = new RoomEntity(year, month, day, hour, minute, second);
                    dao.insert(entity);

                    roomtextdebug.setText("書き込み完了");
                    listpage = listmax + 1;

                    loaddb();

                } catch(Exception e) {
                    roomtextdebug.setText("エラー");
                }

            }
        });
    }

    private void deletedb() {
        ExecutorService executor = Executors.newSingleThreadExecutor();
        executor.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    RoomTimeDatabase db = Room.databaseBuilder(getApplicationContext(),
                            RoomTimeDatabase.class, "roomtime").build();

                    RoomTimeDao dao = db.roomtimedao();

                    dao.delete(listid);
                    listpage = 1;

                    loaddb();
                } catch (Exception e) {
                    roomtextdebug.setText("エラー");
                }
            }
        });
    }

    private void deletealldb() {
        ExecutorService executor = Executors.newSingleThreadExecutor();
        executor.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    RoomTimeDatabase db = Room.databaseBuilder(getApplicationContext(),
                            RoomTimeDatabase.class, "roomtime").build();

                    RoomTimeDao dao = db.roomtimedao();

                    dao.deleteall();
                    listpage = 1;

                    loaddb();
                } catch (Exception e) {
                    roomtextdebug.setText("エラー");
                }
            }
        });
    }



    @Override
    public void onClick(View v) {
        switch(v.getId()) {
            case(R.id.roombtnadd):
                writedb();
                break;

            case(R.id.roombtnleft):
                if(listpage > 1) {
                    listpage -= 1;
                    loaddb();
                    roomtextdebug.setText("");
                }
                break;

            case(R.id.roombtnright):
                if(listpage < listmax) {
                    listpage += 1;
                    loaddb();
                    roomtextdebug.setText("");
                }
                break;

            case(R.id.roombtndelete):
                deletedb();
                break;

            case(R.id.roombtnalldelete):
                deletealldb();
                break;
        }
    }
}

RoomEntity.java

package uta.utauta.roomdb;

import androidx.room.Entity;
import androidx.room.PrimaryKey;

@Entity(tableName = "roomtime")
public class RoomEntity {

    @PrimaryKey(autoGenerate = true)
    public int id;
    public int year;
    public int month;
    public int day;
    public int hour;
    public int minute;
    public int second;

    public RoomEntity(int year, int month, int day, int hour, int minute, int second) {

        this.year = year;
        this.month = month;
        this.day = day;
        this.hour = hour;
        this.minute = minute;
        this.second = second;

    }

    public int getId() {
        return this.id;
    }

    public int getyear() {
        return this.year;
    }

    public int getmonth() {
        return this.month;
    }

    public int getday() {
        return this.day;
    }

    public int gethour() {
        return this.hour;
    }

    public int getminute() {
        return this.minute;
    }

    public int getsecond() {
        return this.second;
    }

}

RoomTimeDao

package uta.utauta.roomdb;

import androidx.room.Dao;
import androidx.room.Insert;
import androidx.room.Query;

import java.util.List;

@Dao
public interface RoomTimeDao {

    @Query("SELECT * FROM roomtime")
    List<RoomEntity> getall();

    @Query("DELETE FROM roomtime")
    void deleteall();

    @Query("DELETE FROM roomtime WHERE id = :x")
    void delete(int x);

    @Insert
    void insert(RoomEntity roomentity);

}

RoomTimeDatabase

package uta.utauta.roomdb;

import androidx.room.Database;
import androidx.room.RoomDatabase;

@Database(entities = {RoomEntity.class}, version = 1, exportSchema = false)
public abstract class RoomTimeDatabase extends RoomDatabase {

    public abstract RoomTimeDao roomtimedao();

}