[안드로이드 앱 서버 만들기] 5. 안드로이드 앱과 서버 통신

게시된 내용은 작성자가 공부한 내용을 정리하여 기록하였습니다. 일부 빠지거나 부족한 부분이 있을 수 있습니다. 최대한 편집 없이 기록하였습니다.

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사용 도구 : STS 4 (Spring Tools Suite), AWS EC2, MariaDB, Windows, Android Studio

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아래와 같은 앱을 만들겠습니다.

이름, 나이, 주소를 넣고 ADD를 누르면 DB에 추가 됩니다.

수정을 눌러서 이름, 나이, 주소를 수정합니다.

삭제를 눌러서 데이터를 삭제합니다.

 

 

 

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1. 안드로이드 프로젝트 생성

안드로이드 프로젝트를 생성하겠습니다. Empty Activity를 선택합니다. 

그리고 프로젝트 이름을 정하고, Java를 선택합니다.

 

 

 

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2. 설정 추가

Lombok, RecyclerView, Retrofit, Gson 라이브러리를 추가합니다.

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'

    // Lombok
    compileOnly 'org.projectlombok:lombok:1.18.8'
    annotationProcessor 'org.projectlombok:lombok:1.18.8'

    // RecyclerView
    implementation "androidx.recyclerview:recyclerview:1.1.0"

    // Retrofit
    implementation 'com.squareup.retrofit2:retrofit:2.5.0'
    implementation 'com.squareup.retrofit2:converter-gson:2.5.0'

    // Gson
    implementation 'com.google.code.gson:gson:2.8.5'
}

 

 

 

AndroidManifest.xml에 인터넷 권한을 추가합니다.

<uses-permission android:name="android.permission.INTERNET"/>

 

 

 

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3.  레이아웃 만들기

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    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"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/et_name"
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:hint="NAME"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/et_age"
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:hint="AGE"
        app:layout_constraintStart_toEndOf="@+id/et_name"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/et_address"
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:hint="ADDRESS"
        app:layout_constraintStart_toEndOf="@+id/et_age"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:layout_width="69dp"
        android:layout_height="46dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:text="Add"
        android:id="@+id/btn_add"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="68dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:text="MemberList"
        android:textColor="#000"
        android:textSize="25sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />


    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/member_list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

</androidx.constraintlayout.widget.ConstraintLayout>

 

 

member_info.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="wrap_content"
    android:layout_margin="3dp"
    android:background="@drawable/border_shadow"
    android:orientation="vertical">


    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:id="@+id/info_layout">

        <TextView
            android:id="@+id/info_id"
            android:layout_width="50dp"
            android:layout_height="40dp"
            android:text="ID"
            android:gravity="center"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="8dp"
            android:layout_marginBottom="8dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/info_name"
            android:layout_width="60dp"
            android:layout_height="40dp"
            android:text="NAME"
            android:gravity="center"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="8dp"
            android:layout_marginBottom="8dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toEndOf="@+id/info_id"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/info_age"
            android:layout_width="60dp"
            android:layout_height="40dp"
            android:text="AGE"
            android:gravity="center"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="8dp"
            android:layout_marginBottom="8dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toEndOf="@+id/info_name"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/info_address"
            android:layout_width="75dp"
            android:layout_height="40dp"
            android:text="ADDRESS"
            android:gravity="center"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="8dp"
            android:layout_marginBottom="8dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toEndOf="@+id/info_age"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/info_created"
            android:layout_width="80dp"
            android:layout_height="40dp"
            android:text="CREATED"
            android:gravity="center"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="8dp"
            android:layout_marginBottom="8dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toEndOf="@+id/info_address"
            app:layout_constraintTop_toTopOf="parent" />

        <Button
            android:id="@+id/info_update"
            android:layout_width="31dp"
            android:layout_height="18dp"
            android:layout_marginTop="5dp"
            android:layout_marginEnd="4dp"
            android:layout_marginRight="4dp"
            android:background="#f0f0f0"
            android:text="수정"
            android:textSize="8sp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <Button
            android:id="@+id/info_delete"
            android:layout_width="31dp"
            android:layout_height="18dp"
            android:layout_marginTop="4dp"
            android:layout_marginEnd="4dp"
            android:layout_marginRight="4dp"
            android:background="#f0f0f0"
            android:text="삭제"
            android:textSize="8sp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/info_update" />

    </androidx.constraintlayout.widget.ConstraintLayout>


    <androidx.constraintlayout.widget.ConstraintLayout
        android:id="@+id/update_layout"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:visibility="gone"
        >

        <TextView
            android:id="@+id/update_id"
            android:layout_width="50dp"
            android:layout_height="40dp"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="5dp"
            android:layout_marginBottom="7dp"
            android:gravity="center"
            android:text="ID"
            android:textSize="10sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <EditText
            android:id="@+id/update_name"
            android:layout_width="60dp"
            android:layout_height="40dp"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="5dp"
            android:layout_marginBottom="7dp"
            android:gravity="center"
            android:text="NAME"
            android:textSize="10sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toEndOf="@+id/update_id"
            app:layout_constraintTop_toTopOf="parent" />

        <EditText
            android:id="@+id/update_age"
            android:layout_width="60dp"
            android:layout_height="40dp"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="5dp"
            android:layout_marginBottom="7dp"
            android:gravity="center"
            android:text="AGE"
            android:textSize="10sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toEndOf="@+id/update_name"
            app:layout_constraintTop_toTopOf="parent" />

        <EditText
            android:id="@+id/update_address"
            android:layout_width="75dp"
            android:layout_height="40dp"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="5dp"
            android:layout_marginBottom="7dp"
            android:gravity="center"
            android:text="ADDRESS"
            android:textSize="10sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toEndOf="@+id/update_age"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/update_created"
            android:layout_width="20dp"
            android:layout_height="40dp"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="5dp"
            android:layout_marginBottom="7dp"
            android:gravity="center"
            android:text="CREATED"
            android:textSize="10sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toEndOf="@+id/update_address"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.416" />

        <Button
            android:id="@+id/update_btn"
            android:layout_width="31dp"
            android:layout_height="35dp"
            android:layout_marginStart="4dp"
            android:layout_marginLeft="4dp"
            android:layout_marginTop="6dp"
            android:layout_marginEnd="4dp"
            android:layout_marginRight="4dp"
            android:layout_marginBottom="8dp"
            android:background="#f0f0f0"
            android:text="수정"
            android:textSize="8sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.0"
            app:layout_constraintStart_toEndOf="@+id/update_created"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.0" />

    </androidx.constraintlayout.widget.ConstraintLayout>

</LinearLayout>

 

 

drawable 폴더에

border_shadow.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape android:shape="rectangle">
            <solid android:color="#CABBBBBB"/>
            <corners android:radius="2dp" />
        </shape>
    </item>

    <item
        android:left="1dp"
        android:right="1dp"
        android:top="1dp"
        android:bottom="2dp">
        <shape android:shape="rectangle">
            <solid android:color="@android:color/white"/>
            <corners android:radius="2dp" />
        </shape>
    </item>
</layer-list>

 

 

 

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4. Object 정의

스프링 프로젝트에서 사용했던 Member 객체를 그대로 사용합니다.

Member.Java

package com.example.retrofixtest;

import java.util.Date;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Member {
    private long id;
    private String name;
    private int age;
    private String address;
    private Date createdAt;

    public long getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public String getAddress() {
        return address;
    }

    public Date getCreatedAt(){
        return createdAt;
    }

}

 

 

 

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5. Interface 정의

아래 BASE_URL에 EC2의 퍼블릭 IP를 넣어주세요.

 

DataService.java

package com.example.retrofixtest;

import java.util.List;
import java.util.Map;

import okhttp3.OkHttpClient;
import okhttp3.ResponseBody;
import retrofit2.Call;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;
import retrofit2.http.Body;
import retrofit2.http.GET;
import retrofit2.http.POST;
import retrofit2.http.Path;

public class DataService {
    private String BASE_URL = ""; // TODO REST API 퍼블릭 IP로 변경

    Retrofit retrofitClient =
            new Retrofit.Builder()
                    .baseUrl(BASE_URL)
                    .client(new OkHttpClient.Builder().build())
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();

    SelectAPI select = retrofitClient.create(SelectAPI.class);
    InsertAPI insert = retrofitClient.create(InsertAPI.class);
    UpdateAPI update = retrofitClient.create(UpdateAPI.class);
    DeleteAPI delete = retrofitClient.create(DeleteAPI.class);
}

interface SelectAPI{
    @GET("select/{id}")
    Call<Member> selectOne(@Path("id") long id);

    @GET("select")
    Call<List<Member>> selectAll();
}
interface InsertAPI{
    @POST("insert")
    Call<Member> insertOne(@Body Map<String, String> map);
}

interface UpdateAPI{
    @POST("update/{id}")
    Call<Member> updateOne(@Path("id") long id, @Body Map<String, String> map);
}

interface DeleteAPI{
    @POST("delete/{id}")
    Call<ResponseBody> deleteOne(@Path("id") long id);
}

 

 

 

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6. Adapter 정의

콜백을 객체로 받지 않는 Delete 요청 같은 경우에는 콜백 타입이 String이 아닌 ResponseBody 타입으로 받습니다.

 

MemberAdapter.java

package com.example.retrofixtest;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import androidx.constraintlayout.widget.ConstraintLayout;
import androidx.recyclerview.widget.RecyclerView;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import okhttp3.ResponseBody;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;

public class MemberAdapter extends RecyclerView.Adapter<MemberAdapter.ViewHolder> {

    private List<Member> data;
    private Context context;
    private DataService dataService;

    MemberAdapter(List<Member> data, Context context, DataService dataService) {
        this.data = data;
        this.context = context;
        this.dataService = dataService;
    }

    @Override
    public MemberAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        return new MemberAdapter.ViewHolder(inflater.inflate(R.layout.member_info, parent, false));
    }

    @Override
    public int getItemCount() {
        return data.size() ;
    }

    @Override
    public void onBindViewHolder(final MemberAdapter.ViewHolder holder, final int position) {
        holder.info_id.setText(String.valueOf(data.get(position).getId()));
        holder.info_name.setText(data.get(position).getName());
        holder.info_age.setText(String.valueOf(data.get(position).getAge()));
        holder.info_address.setText(data.get(position).getAddress());
        holder.info_created.setText(dateParser(data.get(position).getCreatedAt()));

        holder.info_update.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                holder.update_id.setText(String.valueOf(data.get(position).getId()));
                holder.update_name.setText(data.get(position).getName());
                holder.update_age.setText(String.valueOf(data.get(position).getAge()));
                holder.update_address.setText(data.get(position).getAddress());
                holder.update_created.setText(data.get(position).getCreatedAt().toString());

                holder.info_layout.setVisibility(View.GONE);
                holder.update_layout.setVisibility(View.VISIBLE);
            }
        });

        holder.info_delete.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                dataService.delete.deleteOne(data.get(position).getId()).enqueue(new Callback<ResponseBody>() {
                    @Override
                    public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
                        data.remove(position);
                        notifyItemRemoved(position);
                        Toast.makeText(context, "아이템 삭제 완료", Toast.LENGTH_SHORT).show();
                    }

                    @Override
                    public void onFailure(Call<ResponseBody> call, Throwable t) {
                        t.printStackTrace();
                    }
                });

            }
        });

        holder.update_btn.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                Map<String, String> map = new HashMap();
                map.put("name", holder.update_name.getText().toString());
                map.put("age", holder.update_age.getText().toString());
                map.put("address", holder.update_address.getText().toString());
                dataService.update.updateOne(data.get(position).getId(), map).enqueue(new Callback<Member>() {
                        @Override
                    public void onResponse(Call<Member> call, Response<Member> response) {
                        data.set(position, response.body());
                        notifyDataSetChanged();
                        Toast.makeText(context, "아이템 수정 완료", Toast.LENGTH_SHORT).show();
                        holder.info_layout.setVisibility(View.VISIBLE);
                        holder.update_layout.setVisibility(View.GONE);
                    }
                    @Override
                    public void onFailure(Call<Member> call, Throwable t) {
                        t.printStackTrace();
                    }
                });
            }
        });
    }

    public String dateParser(Date date){
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("MM/dd hh:mm");
        return simpleDateFormat.format(date);
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        ConstraintLayout info_layout, update_layout;
        TextView info_id, info_name, info_age, info_address, info_created, update_id, update_created;
        Button info_update, info_delete, update_btn;
        EditText update_name, update_age, update_address;

        ViewHolder(View itemView) {
            super(itemView);
            // 뷰 영역
            info_layout = itemView.findViewById(R.id.info_layout);
            info_id = itemView.findViewById(R.id.info_id);
            info_name = itemView.findViewById(R.id.info_name);
            info_age = itemView.findViewById(R.id.info_age);
            info_address = itemView.findViewById(R.id.info_address);
            info_created = itemView.findViewById(R.id.info_created);
            info_update = itemView.findViewById(R.id.info_update);
            info_delete = itemView.findViewById(R.id.info_delete);

            // 수정 영역
            update_layout = itemView.findViewById(R.id.update_layout);
            update_id = itemView.findViewById(R.id.update_id);
            update_name = itemView.findViewById(R.id.update_name);
            update_age = itemView.findViewById(R.id.update_age);
            update_address = itemView.findViewById(R.id.update_address);
            update_created = itemView.findViewById(R.id.update_created);
            update_btn = itemView.findViewById(R.id.update_btn);
        }
    }
}

 

 

 

---

7. MainActivity 정의

 

MainActivity.java

package com.example.retrofixtest;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;

public class MainActivity extends AppCompatActivity {

    DataService dataService = new DataService();
    List<Member> members;

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

        final RecyclerView member_list = findViewById(R.id.member_list);
        final EditText et_name = findViewById(R.id.et_name);
        final EditText et_age = findViewById(R.id.et_age);
        final EditText et_address = findViewById(R.id.et_address);
        member_list.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));

        dataService.select.selectAll().enqueue(new Callback<List<Member>>() {
                    @Override
                    public void onResponse(Call<List<Member>> call, Response<List<Member>> response) {
                        Log.d("test", response.body().toString());
                        members = response.body();
                        setAdapter(member_list);
            }
            @Override
            public void onFailure(Call<List<Member>> call, Throwable t) {
                t.printStackTrace();
            }
        });

        Button btn_add = findViewById(R.id.btn_add);
        btn_add.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                Map<String, String> map = new HashMap();
                map.put("name", et_name.getText().toString());
                map.put("age", et_age.getText().toString());
                map.put("address", et_address.getText().toString());

                dataService.insert.insertOne(map).enqueue(new Callback<Member>() {
                    @Override
                    public void onResponse(Call<Member> call, Response<Member> response) {
                        members.add(response.body());
                        setAdapter(member_list);
                        Toast.makeText(MainActivity.this, "유저 등록 완료", Toast.LENGTH_SHORT).show();
                        et_name.setText("");
                        et_age.setText("");
                        et_address.setText("");
                    }

                    @Override
                    public void onFailure(Call<Member> call, Throwable t) {
                        t.printStackTrace();
                    }
                });
            }
        });
    }

    void setAdapter(RecyclerView member_list){
        member_list.setAdapter(new MemberAdapter(members, this, dataService));
    }
}

 

 

 

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이렇게 안드로이드 앱에서 데이터를 추가/수정/삭제/조회할 수 있는 과정을 모두 알아봤습니다.

이렇게 배운 내용을 통해서 재활 운동 앱 서비스를 만들었습니다. 환자의 재활 상태를 DB에 저장하여 관리하고, 축적된 데이터를 활용하여 환자들이 효율적인 재활이 가능한 앱 서비스입니다.