사진을 포스팅하는 어플리케이션(App) 개발하기

다음 게시물을 참고해, 메인액티비티와 회원가입과 로그인 화면과 Activity를 만들고, config, string을 작성해준다.

 

https://codebunny99.tistory.com/170

회원가입, 로그인, 로그아웃 기능 앱(app)을 Retrofit 라이브러리로 만들기

 

 

 

config의 도메인 주소는,

 

 

 

 

 

포스팅 API를 만든 vscode를 sls deploy 해준 후, 나온 endpoint 주소로 하였다

 

https://codebunny99.tistory.com/117

instargram 사진 포스팅 API (1) 기본 세팅(Setting) 하기

 

 

 

 

 

 

포스트맨에서도 도메인 주소로 잘 실행되는지 점검한 후 진행하였다.

 

 

 

 

 

API 만들기

 

 

 

 

NetworkClient

package com.~.postingapp.api;

import android.content.Context;

import com.~.postingapp.config.Config;

import java.util.concurrent.TimeUnit;

import okhttp3.OkHttpClient;
import okhttp3.logging.HttpLoggingInterceptor;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

public class NetworkClient {
    public static Retrofit retrofit;

    public static Retrofit getRetrofitClient(Context context){
        if(retrofit == null){
            // 통신 로그 확인할때 필요한 코드
            HttpLoggingInterceptor loggingInterceptor =
                    new HttpLoggingInterceptor();
            loggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);

            // 네트워크 연결관련 코드
            OkHttpClient httpClient = new OkHttpClient.Builder()
                    .connectTimeout(1, TimeUnit.MINUTES)
                    .readTimeout(1, TimeUnit.MINUTES)
                    .writeTimeout(1, TimeUnit.MINUTES)
                    .addInterceptor(loggingInterceptor)
                    .build();
            // 네트워크로 데이터를 보내고 받는
            // 레트로핏 라이브러리 관련 코드
            retrofit = new Retrofit.Builder()
                    .baseUrl(Config.DOMAIN)
                    .client(httpClient)
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();
        }
        return retrofit;
    }
}

 

 

 

UserApi

package com.~.postingapp.api;

import com.~.postingapp.model.User;
import com.~.postingapp.model.UserRes;

import retrofit2.Call;
import retrofit2.http.Body;
import retrofit2.http.DELETE;
import retrofit2.http.Header;
import retrofit2.http.POST;

public interface UserApi {

    // 회원가입 API
    // 함수명을 작성해주고, 보낼 데이터는 파라미터에 작성, 받을 데이터는 리턴타입에 작성.
    @POST("/user/register")
    Call<UserRes> register(@Body User user);

    // 로그인 API
    @POST("/user/login")
    Call<UserRes> login(@Body User user);

    // 로그아웃 API
    @DELETE("/user/logout")
    Call<UserRes> logout(@Header("Authorization") String token);
}

 

 

 

 

 

model 패키지 User, UserRes 클래스 만들기

 

 

 

 

fileprovider.xml 파일 생성 후 작성

 

 

 

- 카메라와 앨범 처리를 위한 코드이다.

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <root-path
        name="root"
        path="." />

    <cache-path
        name="cache"
        path="." /> <!--Context.getCacheDir() 내부 저장소-->
    <files-path
        name="files"
        path="." /> <!--Context.getFilesDir() 내부 저장소-->

    <external-path
        name="external"
        path="."/>  <!--  Environment.getExternalStorageDirectory() 외부 저장소-->
    <external-cache-path
        name="external-cache"
        path="."/> <!--  Context.getExternalCacheDir() 외부 저장소-->
    <external-files-path
        name="images"
        path="Pictures" /> <!--  Context.getExternalFilesDir() 외부 저장소-->
</paths>

 

 

 

 

 

AndroidManifest.xml 설정

 

- 환경설정 하기

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

<uses-feature android:name="android.hardware.camera" android:required="true"/>
<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

 

 

 

 

검정색으로 지운 부분은, 자동완성 될 것이다.

 

<provider
    android:authorities="com.~.cameraapp.fileprovider"
    android:name="androidx.core.content.FileProvider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/fileprovider"/>
</provider>

 

 

 

 

 

라이브러리 설치

 

build.gradle.kts(:app) 에서, 맨 아랫줄 작성.

 

    implementation("com.squareup.retrofit2:retrofit:2.11.0")
    implementation("com.squareup.retrofit2:converter-gson:2.11.0")
    implementation("com.squareup.okhttp3:logging-interceptor:4.12.0")

    implementation("com.github.bumptech.glide:glide:4.16.0")
    implementation("commons-io:commons-io:2.4")

 

 

 

activity_main.xml

 

화면 작성

 

<?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:id="@+id/btnAdd"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ProgressBar
            android:id="@+id/progressBar"
            style="?android:attr/progressBarStyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true" />

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_above="@id/button" />

        <Button
            android:id="@+id/button"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_margin="10dp"
            android:text="포스팅 생성"
            android:textSize="24sp" />
    </RelativeLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

 

 

 

 

 

 

Activity 만들어서, activity_add.xml, AddActivity.java 작성하기

 

화면 작성

 

<?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:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".AddActivity">

    <ImageView
        android:id="@+id/imgPhoto"
        android:layout_width="227dp"
        android:layout_height="235dp"
        android:layout_marginStart="80dp"
        android:layout_marginTop="96dp"
        android:layout_marginEnd="80dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/add_photo" />

    <Button
        android:id="@+id/btnSave"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="10dp"
        android:layout_marginTop="32dp"
        android:layout_marginEnd="10dp"
        android:text="포스트 생성"
        android:textSize="24sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editContent" />

    <EditText
        android:id="@+id/editContent"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="10dp"
        android:layout_marginTop="36dp"
        android:layout_marginEnd="10dp"
        android:ems="10"
        android:hint="내용 입력..."
        android:inputType="text"
        android:textSize="24sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imgPhoto" />

</androidx.constraintlayout.widget.ConstraintLayout>

 

 

 

 

Addactivity.java

 

- 화면과 연결하고 로직을 작성하고 카메라, 앨범을 사용하기 위한 코드를 작성하였다.

 

package com.~.postingapp;

import android.annotation.SuppressLint;
import android.app.Dialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.drawable.ColorDrawable;
import android.media.ExifInterface;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.os.ParcelFileDescriptor;
import android.provider.MediaStore;
import android.provider.OpenableColumns;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.core.content.FileProvider;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.text.SimpleDateFormat;
import java.util.Date;

import com.google.android.material.snackbar.Snackbar;
import com.~.postingapp.api.NetworkClient;
import com.~.postingapp.api.PostingApi;
import com.~.postingapp.config.Config;
import com.~.postingapp.model.Res;

import android.Manifest;

import org.apache.commons.io.IOUtils;

import okhttp3.MediaType;
import okhttp3.MultipartBody;
import okhttp3.RequestBody;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;


public class AddActivity extends AppCompatActivity {

    ImageView imgPhoto;
    EditText editContent;
    Button btnSave;

    File photoFile;

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

        imgPhoto = findViewById(R.id.imgPhoto);
        editContent = findViewById(R.id.editContent);
        btnSave = findViewById(R.id.btnSave);

        // 버튼 누르면, 카메라로 찍을것인지, 앨범에서 고를것인지에 대한
        // 알러트 다이얼로그 띄운다.

        imgPhoto.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                showDialog();
            }
        });

        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                // 파일이 있어야 하고 내용이 있어야 한다
                String content = editContent.getText().toString().trim();

                if(content.isEmpty() || photoFile == null){
                    Snackbar.make(btnSave, "사진과 내용은 필수항목입니다",Snackbar.LENGTH_SHORT).show();
                    return;
                }

                // 레트로핏 라이브러리 이용해서 네트워크로 호출한다.
                showProgress();
                Retrofit retrofit = NetworkClient.getRetrofitClient(AddActivity.this);
                PostingApi api = retrofit.create(PostingApi.class);

                SharedPreferences sp = getSharedPreferences(Config.SP_NAME, MODE_PRIVATE);
                String token = sp.getString("token","");

                // 보낼 이미지 파일 만들기
                RequestBody fileBody = RequestBody.create(photoFile, MediaType.parse("image/jpeg"));
                MultipartBody.Part image = MultipartBody.Part.createFormData("image", photoFile.getName(), fileBody);

                // 보낼 텍스트(content) 만들기
                RequestBody textBody = RequestBody.create(content, MediaType.parse("text/plain"));

                Call<Res> call = api.addPosting("Bearer " + token, image, textBody);

                call.enqueue(new Callback<Res>() {
                    @Override
                    public void onResponse(Call<Res> call, Response<Res> response) {
                        dismissProgress();

                        if(response.isSuccessful()){

                            Snackbar.make(btnSave, "잘 저장되었습니다.", Snackbar.LENGTH_SHORT).show();
                            finish();

                        } else {

                        }

                    }

                    @Override
                    public void onFailure(Call<Res> call, Throwable throwable) {
                        dismissProgress();
                    }
                });
            }
        });

    }

    private void showDialog(){
        AlertDialog.Builder builder = new AlertDialog.Builder(AddActivity.this);
        builder.setTitle(R.string.alert_title);
        builder.setItems(R.array.alert_photo, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                if(i == 0){
                    // 첫번째 항목 눌렀을때
                    // 카메라로 사진찍기
                    camera();

                }else if(i == 1){
                    // 두번째 항목 눌렀을때
                    album();
                }
            }
        });
        builder.show();
    }


    private void camera(){
        int permissionCheck = ContextCompat.checkSelfPermission(
                AddActivity.this, Manifest.permission.CAMERA);

        if(permissionCheck != PackageManager.PERMISSION_GRANTED){
            ActivityCompat.requestPermissions(AddActivity.this,
                    new String[]{android.Manifest.permission.CAMERA} ,
                    1000);
            Toast.makeText(AddActivity.this, "카메라 권한 필요합니다.",
                    Toast.LENGTH_SHORT).show();
            return;
        } else {
            Intent i = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            if(i.resolveActivity(AddActivity.this.getPackageManager())  != null  ){

                // 사진의 파일명을 만들기
                String fileName = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
                photoFile = getPhotoFile(fileName);

                Uri fileProvider = FileProvider.getUriForFile(AddActivity.this,Config.FILE_PROVIDER,photoFile);
                i.putExtra(MediaStore.EXTRA_OUTPUT, fileProvider);
                startActivityForResult(i, 100);

            } else{
                Toast.makeText(AddActivity.this, "이폰에는 카메라 앱이 없습니다.",
                        Toast.LENGTH_SHORT).show();
            }
        }


    }

    private void album(){
        if(checkPermission()){
            displayFileChoose();
        }else{
            requestPermission();
        }
    }

    private boolean checkPermission(){
        int result = ContextCompat.checkSelfPermission(AddActivity.this,
                Manifest.permission.WRITE_EXTERNAL_STORAGE);
        if(result == PackageManager.PERMISSION_DENIED){
            return false;
        }else{
            return true;
        }
    }

    private void requestPermission() {
        if(ActivityCompat.shouldShowRequestPermissionRationale(AddActivity.this,
                Manifest.permission.WRITE_EXTERNAL_STORAGE)){
            Log.i("DEBUGGING5", "true");
            Toast.makeText(AddActivity.this, "권한 수락이 필요합니다.",
                    Toast.LENGTH_SHORT).show();
        }else{
            Log.i("DEBUGGING6", "false");
            ActivityCompat.requestPermissions(AddActivity.this,
                    new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 500);
        }
    }

    private void displayFileChoose() {
        Intent i = new Intent();
        i.setType("image/*");
        i.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(Intent.createChooser(i, "SELECT IMAGE"), 300);
    }

    private File getPhotoFile(String fileName) {
        File storageDirectory = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        try{
            return File.createTempFile(fileName, ".jpg", storageDirectory);
        }catch (IOException e){
            e.printStackTrace();
            return null;
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case 1000: {
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    Toast.makeText(AddActivity.this, "권한 허가 되었음",
                            Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(AddActivity.this, "아직 승인하지 않았음",
                            Toast.LENGTH_SHORT).show();
                }
                break;
            }
            case 500: {
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    Toast.makeText(AddActivity.this, "권한 허가 되었음",
                            Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(AddActivity.this, "아직 승인하지 않았음",
                            Toast.LENGTH_SHORT).show();
                }

            }

        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if(requestCode == 100 && resultCode == RESULT_OK){

            Bitmap photo = BitmapFactory.decodeFile(photoFile.getAbsolutePath());

            ExifInterface exif = null;
            try {
                exif = new ExifInterface(photoFile.getAbsolutePath());
            } catch (IOException e) {
                e.printStackTrace();
            }
            int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION,
                    ExifInterface.ORIENTATION_UNDEFINED);
            photo = rotateBitmap(photo, orientation);

            // 압축시킨다. 해상도 낮춰서
            OutputStream os;
            try {
                os = new FileOutputStream(photoFile);
                photo.compress(Bitmap.CompressFormat.JPEG, 20, os);
                os.flush();
                os.close();
            } catch (Exception e) {
                Log.e(getClass().getSimpleName(), "Error writing bitmap", e);
            }

            photo = BitmapFactory.decodeFile(photoFile.getAbsolutePath());

            imgPhoto.setImageBitmap(photo);
            imgPhoto.setScaleType(ImageView.ScaleType.CENTER_CROP);

            // 네트워크로 데이터 보낸다.



        }else if(requestCode == 300 && resultCode == RESULT_OK && data != null &&
                data.getData() != null){

            Uri albumUri = data.getData( );
            String fileName = getFileName( albumUri );
            try {

                ParcelFileDescriptor parcelFileDescriptor = getContentResolver( ).openFileDescriptor( albumUri, "r" );
                if ( parcelFileDescriptor == null ) return;
                FileInputStream inputStream = new FileInputStream( parcelFileDescriptor.getFileDescriptor( ) );
                photoFile = new File( this.getCacheDir( ), fileName );
                FileOutputStream outputStream = new FileOutputStream( photoFile );
                IOUtils.copy( inputStream, outputStream );

//                //임시파일 생성
//                File file = createImgCacheFile( );
//                String cacheFilePath = file.getAbsolutePath( );


                // 압축시킨다. 해상도 낮춰서
                Bitmap photo = BitmapFactory.decodeFile(photoFile.getAbsolutePath());
                OutputStream os;
                try {
                    os = new FileOutputStream(photoFile);
                    photo.compress(Bitmap.CompressFormat.JPEG, 20, os);
                    os.flush();
                    os.close();
                } catch (Exception e) {
                    Log.e(getClass().getSimpleName(), "Error writing bitmap", e);
                }

                imgPhoto.setImageBitmap(photo);
                imgPhoto.setScaleType(ImageView.ScaleType.CENTER_INSIDE);

//                imageView.setImageBitmap( getBitmapAlbum( imageView, albumUri ) );

            } catch ( Exception e ) {
                e.printStackTrace( );
            }

            // 네트워크로 보낸다.
        }
        super.onActivityResult(requestCode, resultCode, data);
    }

    //앨범에서 선택한 사진이름 가져오기
    public String getFileName( Uri uri ) {
        Cursor cursor = getContentResolver( ).query( uri, null, null, null, null );
        try {
            if ( cursor == null ) return null;
            cursor.moveToFirst( );
            @SuppressLint("Range") String fileName = cursor.getString( cursor.getColumnIndex( OpenableColumns.DISPLAY_NAME ) );
            cursor.close( );
            return fileName;

        } catch ( Exception e ) {
            e.printStackTrace( );
            cursor.close( );
            return null;
        }
    }


    public static Bitmap rotateBitmap(Bitmap bitmap, int orientation) {

        Matrix matrix = new Matrix();
        switch (orientation) {
            case ExifInterface.ORIENTATION_NORMAL:
                return bitmap;
            case ExifInterface.ORIENTATION_FLIP_HORIZONTAL:
                matrix.setScale(-1, 1);
                break;
            case ExifInterface.ORIENTATION_ROTATE_180:
                matrix.setRotate(180);
                break;
            case ExifInterface.ORIENTATION_FLIP_VERTICAL:
                matrix.setRotate(180);
                matrix.postScale(-1, 1);
                break;
            case ExifInterface.ORIENTATION_TRANSPOSE:
                matrix.setRotate(90);
                matrix.postScale(-1, 1);
                break;
            case ExifInterface.ORIENTATION_ROTATE_90:
                matrix.setRotate(90);
                break;
            case ExifInterface.ORIENTATION_TRANSVERSE:
                matrix.setRotate(-90);
                matrix.postScale(-1, 1);
                break;
            case ExifInterface.ORIENTATION_ROTATE_270:
                matrix.setRotate(-90);
                break;
            default:
                return bitmap;
        }
        try {
            Bitmap bmRotated = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
            bitmap.recycle();
            return bmRotated;
        }
        catch (OutOfMemoryError e) {
            e.printStackTrace();
            return null;
        }
    }

    // 서버에 데이터를 저장하거나, 수정하거나, 삭제하는 경우에 사용한다!
    Dialog dialog;
    void showProgress(){
        dialog = new Dialog(this);
        dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
        dialog.setContentView(new ProgressBar(this));
        dialog.setCancelable(false);
        dialog.setCanceledOnTouchOutside(false);
        dialog.show();
    }
    void dismissProgress(){
        dialog.dismiss();
    }
    
}

 

 

 

 

PostingApi 클래스 만들기

 

 

package com.~.postingapp.api;

import com.~.postingapp.model.Res;

import okhttp3.MultipartBody;
import okhttp3.RequestBody;
import retrofit2.Call;
import retrofit2.http.Header;
import retrofit2.http.POST;
import retrofit2.http.Part;

public interface PostingApi {

    @POST("/posting")
    Call<Res> addPosting(@Header("Authorization") String token,
                         @Part MultipartBody.Part image,  //파트로 나눠서 보내라 용량 크므로
                         @Part("content")RequestBody content);
}

 

 

@Part MultipartBody 

- Retrofit 라이브러리를 사용하여 멀티파트 파일 업로드를 구현할 때 사용되는 애노테이션이다.

- 이를 통해 파일 및 데이터를 서버로 전송할 수 있다.

 

 

 

 

 

Res 클래스 만들기

 

 

 

 

 

 

activity_row 만들기

 

 

<?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"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <androidx.cardview.widget.CardView
        android:id="@+id/cardView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:layout_marginTop="5dp"
        android:layout_marginRight="10dp"
        android:layout_marginBottom="5dp">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:orientation="horizontal">

            <ImageView
                android:id="@+id/imgPhoto"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:layout_weight="4"
                app:srcCompat="@drawable/add_photo" />

            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_weight="5"
                android:orientation="vertical">

                <TextView
                    android:id="@+id/txtContent"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="TextView"
                    android:textColor="#000000"
                    android:textSize="23sp" />

                <TextView
                    android:id="@+id/txtEmail"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="TextView"
                    android:textColor="#000000"
                    android:textSize="23sp" />

                <TextView
                    android:id="@+id/txtCreatedAt"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="TextView"
                    android:textColor="#000000"
                    android:textSize="23sp" />

                <ImageView
                    android:id="@+id/imgLike"
                    android:src="@drawable/like_24dp"
                    android:layout_width="35dp"
                    android:layout_height="35dp" />

            </LinearLayout>

        </LinearLayout>
    </androidx.cardview.widget.CardView>
</LinearLayout>

 

 

 

 

 

 

MainActivity. java 작성

 

package com.~.postingapp;

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;

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

import com.~.postingapp.adapter.PostingAdapter;
import com.~.postingapp.api.NetworkClient;
import com.~.postingapp.api.PostingApi;
import com.~.postingapp.config.Config;
import com.~.postingapp.model.Posting;
import com.~.postingapp.model.PostingList;

import java.util.ArrayList;

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

public class MainActivity extends AppCompatActivity {

    ProgressBar progressBar;
    Button btnAdd;
    RecyclerView recyclerView;
    ArrayList<Posting> postingArrayList = new ArrayList<>();
    PostingAdapter adapter;

    String token;

    // 페이징 처리에 필요한 멤버 변수들!!
    int offset = 0;
    int limit = 5;
    int count;

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

        SharedPreferences sp = getSharedPreferences(Config.SP_NAME, MODE_PRIVATE);
        token = sp.getString("token", "");
        if(token.isEmpty()){
            Intent intent = new Intent(MainActivity.this, LoginActivity.class);
            startActivity(intent);
            finish();
            return;
        }

        progressBar = findViewById(R.id.progressBar);
        btnAdd = findViewById(R.id.btnAdd);
        recyclerView = findViewById(R.id.recyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
            }

            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);

                int lastPosition = ((LinearLayoutManager)recyclerView.getLayoutManager()).findLastCompletelyVisibleItemPosition();
                int totalCount = recyclerView.getAdapter().getItemCount();

                if(lastPosition + 1 == totalCount){

                    if(count == limit){
                        // 데이터를 추가로 요청한다.
                        addNetworkData();
                    }
                }

            }
        });

        btnAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, AddActivity.class);
                startActivity(intent);
            }
        });


    }

    private void addNetworkData() {

        progressBar.setVisibility(View.VISIBLE);

        Retrofit retrofit = NetworkClient.getRetrofitClient(MainActivity.this);

        PostingApi api = retrofit.create(PostingApi.class);

        Call<PostingList> call = api.getPostingList("Bearer " + token, offset, limit );

        call.enqueue(new Callback<PostingList>() {
            @Override
            public void onResponse(Call<PostingList> call, Response<PostingList> response) {
                progressBar.setVisibility(View.GONE);

                if(response.isSuccessful()){
                    PostingList postingList = response.body();

                    count = postingList.count;

                    offset = offset + count;

                    postingArrayList.addAll( postingList.items );

                    adapter.notifyDataSetChanged();

                }else{

                }
            }

            @Override
            public void onFailure(Call<PostingList> call, Throwable throwable) {
                progressBar.setVisibility(View.GONE);
            }
        });

    }

    @Override
    protected void onResume() {
        super.onResume();

        // 네트워크를 통해서 데이터를 받아온다.
        getNetworkData();

    }

    private void getNetworkData() {

        progressBar.setVisibility(View.VISIBLE);

        postingArrayList.clear();

        offset = 0;

        Retrofit retrofit = NetworkClient.getRetrofitClient(MainActivity.this);

        PostingApi api = retrofit.create(PostingApi.class);

        Call<PostingList> call = api.getPostingList("Bearer "+token, offset, limit);

        call.enqueue(new Callback<PostingList>() {
            @Override
            public void onResponse(Call<PostingList> call, Response<PostingList> response) {
                progressBar.setVisibility(View.GONE);

                if(response.isSuccessful()){
                    PostingList postingList = response.body();

                    count = postingList.count;

                    offset = offset + count;

                    postingArrayList.addAll( postingList.items );

                    adapter = new PostingAdapter(MainActivity.this, postingArrayList);

                    recyclerView.setAdapter(adapter);

                }else{

                }

            }

            @Override
            public void onFailure(Call<PostingList> call, Throwable throwable) {
                progressBar.setVisibility(View.GONE);
            }
        });

    }
}

 

 

 

 

Posting 클래스 만들기

 

 

package com.~.postingapp.model;

public class Posting {
    public int id;
    public int userId;
    public String imageUrl;
    public String content;
    public String createdAt;
    public String updatedAt;
    public String email;
    public int isLike;
}

 

 

 

 

 

PostingList 클래스 만들기

 

package com.~.postingapp.model;

import java.util.ArrayList;

public class PostingList {

    public String result;
    public ArrayList<Posting> items;
    public int count;

}

 

 

 

 

 

 

PostingAdapter 만들기

 

- activity_row와 MainActivity의 화면을 연결해준다.

package com.~.postingapp.adapter;

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

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.bumptech.glide.Glide;
import com.~.postingapp.R;
import com.~.postingapp.model.Posting;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.TimeZone;

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

    Context context;
    ArrayList<Posting> postingArrayList;

    SimpleDateFormat sf;
    SimpleDateFormat df;

    public PostingAdapter(Context context, ArrayList<Posting> postingArrayList) {
        this.context = context;
        this.postingArrayList = postingArrayList;

        //2024-05-30T07:23:52
        sf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
        df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        sf.setTimeZone(TimeZone.getTimeZone("UTC"));
        df.setTimeZone(TimeZone.getDefault());

    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.activity_row, parent, false);
        return new PostingAdapter.ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {

        Posting posting = postingArrayList.get(position);

        Glide.with(context).load( posting.imageUrl ).into( holder.imgPhoto );

        holder.txtContent.setText( posting.content );
        holder.txtEmail.setText( posting.email );
        holder.txtCreatedAt.setText( posting.createdAt );

        if( posting.isLike == 0 ){
            holder.imgLike.setImageResource(R.drawable.like_24dp);
        }else{
            holder.imgLike.setImageResource(R.drawable.like2);
        }

        try {
            Date date = sf.parse( posting.createdAt );
            String localTime = df.format(date);
            holder.txtCreatedAt.setText(localTime);
        } catch (ParseException e) {
            // 로그를 남겨서 디버깅한다.
        }

    }

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

    public class ViewHolder extends RecyclerView.ViewHolder{
        ImageView imgPhoto;
        TextView txtContent;
        TextView txtEmail;
        TextView txtCreatedAt;
        ImageView imgLike;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);

            imgPhoto = itemView.findViewById(R.id.imgPhoto);
            txtContent = itemView.findViewById(R.id.txtContent);
            txtEmail = itemView.findViewById(R.id.txtEmail);
            txtCreatedAt = itemView.findViewById(R.id.txtCreatedAt);
            imgLike = itemView.findViewById(R.id.imgLike);
        }
    }
}

 

 

 

 

 

PostingApi 만들기

 

package com.~.postingapp.api;

import com.~.postingapp.model.PostingList;
import com.~.postingapp.model.Res;

import okhttp3.MultipartBody;
import okhttp3.RequestBody;
import retrofit2.Call;
import retrofit2.http.GET;
import retrofit2.http.Header;
import retrofit2.http.POST;
import retrofit2.http.Part;
import retrofit2.http.Query;

public interface PostingApi {

    // 포스팅 생성 API
    @POST("/posting")
    Call<Res> addPosting(@Header("Authorization") String token,
                         @Part MultipartBody.Part image,
                         @Part("content") RequestBody content);

    // 친구들의 포스팅 리스트 가져오는 API
    @GET("/posting")
    Call<PostingList> getPostingList(@Header("Authorization") String token,
                                     @Query("offset") int offset,
                                     @Query("limit") int limit);

}