Feat: 사용자 설정 기능 구현 (포트, 루트 디렉토리)

- FTPConfig 클래스 생성: SharedPreferences 기반 설정 관리
  * 포트 번호 저장/로드
  * 루트 디렉토리 URI 및 경로 저장/로드
- MainActivity UI 업데이트
  * ScrollView로 전체 레이아웃 감싸기
  * 설정 섹션 추가 (포트 입력, 디렉토리 선택)
  * Storage Access Framework로 디렉토리 선택 기능
  * 설정 유효성 검사 (포트 범위: 1024-65535)
- MainActivity 로직 업데이트
  * ActivityResultLauncher로 디렉토리 선택
  * takePersistableUriPermission으로 지속적 권한 획득
  * 설정 로드 및 저장 기능
  * 서버 시작 전 루트 디렉토리 필수 체크
- FTPService 수정
  * Intent로 포트 및 루트 디렉토리 전달받음
  * FTPServer에 설정값 전달
- FTPServer 생성자 확장
  * 포트 및 루트 디렉토리 파라미터 추가
  * FTPSession에 설정값 전달
- FTPSession 생성자 확장
  * 루트 디렉토리 파라미터 추가
  * FTPFileSystem에 전달
- FTPFileSystem 생성자 확장
  * 사용자 지정 루트 디렉토리 지원
  * null일 경우 기본 디렉토리 사용
  * 경로 유효성 검증

이제 사용자가 원하는 디렉토리를 FTP 루트로 설정 가능
Android 11+ Scoped Storage 문제 해결

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

app/src/main/java/be/gyu/android/server/ftp/FTPConfig.java

@@ -0,0 +1,63 @@
+package be.gyu.android.server.ftp;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.net.Uri;
+
+public class FTPConfig {
+    private static final String PREF_NAME = "FTPServerConfig";
+    private static final String KEY_PORT = "ftp_port";
+    private static final String KEY_ROOT_DIR_URI = "root_directory_uri";
+    private static final String KEY_ROOT_DIR_PATH = "root_directory_path";
+
+    private static final int DEFAULT_PORT = 2121;
+
+    private final SharedPreferences preferences;
+
+    public FTPConfig(Context context) {
+        this.preferences = context.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
+    }
+
+    public int getPort() {
+        return preferences.getInt(KEY_PORT, DEFAULT_PORT);
+    }
+
+    public void setPort(int port) {
+        preferences.edit().putInt(KEY_PORT, port).apply();
+    }
+
+    public String getRootDirectoryUri() {
+        return preferences.getString(KEY_ROOT_DIR_URI, null);
+    }
+
+    public void setRootDirectoryUri(String uriString) {
+        preferences.edit().putString(KEY_ROOT_DIR_URI, uriString).apply();
+    }
+
+    public String getRootDirectoryPath() {
+        return preferences.getString(KEY_ROOT_DIR_PATH, null);
+    }
+
+    public void setRootDirectoryPath(String path) {
+        preferences.edit().putString(KEY_ROOT_DIR_PATH, path).apply();
+    }
+
+    public boolean hasRootDirectory() {
+        return getRootDirectoryPath() != null && !getRootDirectoryPath().isEmpty();
+    }
+
+    public void clearRootDirectory() {
+        preferences.edit()
+                .remove(KEY_ROOT_DIR_URI)
+                .remove(KEY_ROOT_DIR_PATH)
+                .apply();
+    }
+
+    public void saveSettings(int port, String rootDirUri, String rootDirPath) {
+        preferences.edit()
+                .putInt(KEY_PORT, port)
+                .putString(KEY_ROOT_DIR_URI, rootDirUri)
+                .putString(KEY_ROOT_DIR_PATH, rootDirPath)
+                .apply();
+    }
+}

app/src/main/java/be/gyu/android/server/ftp/FTPServer.java

@@ -19,13 +19,19 @@ public class FTPServer {
     private Thread acceptThread;
     private boolean isRunning = false;
     private int port;
+    private String rootDirectory;
 
     public FTPServer() {
-        this(DEFAULT_PORT);
+        this(DEFAULT_PORT, null);
     }
 
     public FTPServer(int port) {
+        this(port, null);
+    }
+
+    public FTPServer(int port, String rootDirectory) {
         this.port = port;
+        this.rootDirectory = rootDirectory;
         this.executorService = Executors.newFixedThreadPool(MAX_CONNECTIONS);
     }
 
@@ -46,7 +52,7 @@ public class FTPServer {
                         Socket clientSocket = serverSocket.accept();
                         Log.i(TAG, "New client connection from: " + clientSocket.getInetAddress());
 
-                        FTPSession session = new FTPSession(clientSocket);
+                        FTPSession session = new FTPSession(clientSocket, rootDirectory);
                         executorService.execute(session);
 
                     } catch (IOException e) {

app/src/main/java/be/gyu/android/server/ftp/FTPService.java

@@ -35,7 +35,9 @@ public class FTPService extends Service {
             String action = intent.getAction();
 
             if (ACTION_START.equals(action)) {
-                startFTPServer();
+                int port = intent.getIntExtra("port", 2121);
+                String rootDir = intent.getStringExtra("rootDir");
+                startFTPServer(port, rootDir);
             } else if (ACTION_STOP.equals(action)) {
                 stopFTPServer();
             }
@@ -44,19 +46,19 @@ public class FTPService extends Service {
         return START_STICKY;
     }
 
-    private void startFTPServer() {
+    private void startFTPServer(int port, String rootDir) {
         if (ftpServer != null && ftpServer.isRunning()) {
             Log.w(TAG, "FTP Server is already running");
             return;
         }
 
-        ftpServer = new FTPServer();
+        ftpServer = new FTPServer(port, rootDir);
         ftpServer.start();
 
         Notification notification = createNotification("FTP Server is running on port " + ftpServer.getPort());
         startForeground(NOTIFICATION_ID, notification);
 
-        Log.i(TAG, "FTP Server started");
+        Log.i(TAG, "FTP Server started on port " + port + " with root: " + rootDir);
     }
 
     private void stopFTPServer() {

app/src/main/java/be/gyu/android/server/ftp/FTPSession.java

@@ -24,8 +24,12 @@ public class FTPSession implements Runnable {
     private String transferType = "A"; // A = ASCII, I = Binary
 
     public FTPSession(Socket socket) {
+        this(socket, null);
+    }
+
+    public FTPSession(Socket socket, String rootDirectory) {
         this.controlSocket = socket;
-        this.fileSystem = new FTPFileSystem();
+        this.fileSystem = new FTPFileSystem(rootDirectory);
         this.dataConnection = null;
     }
 

app/src/main/java/be/gyu/android/server/ftp/MainActivity.java

@@ -1,15 +1,20 @@
 package be.gyu.android.server.ftp;
 
+import androidx.activity.result.ActivityResultLauncher;
+import androidx.activity.result.contract.ActivityResultContracts;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.core.app.ActivityCompat;
 import androidx.core.content.ContextCompat;
+import androidx.documentfile.provider.DocumentFile;
 
 import android.Manifest;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.widget.Button;
+import android.widget.EditText;
 import android.widget.TextView;
 import android.widget.Toast;
 
@@ -18,9 +23,17 @@ public class MainActivity extends AppCompatActivity {
     private static final int PERMISSION_REQUEST_CODE = 100;
 
     private TextView statusTextView;
+    private TextView portTextView;
     private Button startButton;
     private Button stopButton;
 
+    private EditText portEditText;
+    private TextView rootDirPathTextView;
+    private Button selectDirButton;
+    private Button saveSettingsButton;
+
+    private FTPConfig config;
+    private ActivityResultLauncher<Uri> directoryPickerLauncher;
     private boolean isServerRunning = false;
 
     @Override
@@ -28,20 +41,107 @@ public class MainActivity extends AppCompatActivity {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
 
+        config = new FTPConfig(this);
+
+        setupDirectoryPicker();
         initViews();
+        loadSettings();
         setupListeners();
         requestPermissions();
     }
 
+    private void setupDirectoryPicker() {
+        directoryPickerLauncher = registerForActivityResult(
+                new ActivityResultContracts.OpenDocumentTree(),
+                uri -> {
+                    if (uri != null) {
+                        getContentResolver().takePersistableUriPermission(
+                                uri,
+                                Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION
+                        );
+
+                        DocumentFile pickedDir = DocumentFile.fromTreeUri(this, uri);
+                        if (pickedDir != null && pickedDir.isDirectory()) {
+                            String path = uri.getPath();
+                            if (path != null) {
+                                path = path.replace("/tree/primary:", "/storage/emulated/0/");
+                                path = path.replace("/tree/", "/");
+                            }
+                            rootDirPathTextView.setText(path != null ? path : uri.toString());
+                            config.setRootDirectoryUri(uri.toString());
+                            config.setRootDirectoryPath(path);
+                            Toast.makeText(this, "Directory selected", Toast.LENGTH_SHORT).show();
+                        }
+                    }
+                }
+        );
+    }
+
     private void initViews() {
         statusTextView = findViewById(R.id.statusTextView);
+        portTextView = findViewById(R.id.portTextView);
         startButton = findViewById(R.id.startButton);
         stopButton = findViewById(R.id.stopButton);
+
+        portEditText = findViewById(R.id.portEditText);
+        rootDirPathTextView = findViewById(R.id.rootDirPathTextView);
+        selectDirButton = findViewById(R.id.selectDirButton);
+        saveSettingsButton = findViewById(R.id.saveSettingsButton);
+    }
+
+    private void loadSettings() {
+        int port = config.getPort();
+        String rootPath = config.getRootDirectoryPath();
+
+        portEditText.setText(String.valueOf(port));
+        portTextView.setText("Port: " + port);
+
+        if (rootPath != null && !rootPath.isEmpty()) {
+            rootDirPathTextView.setText(rootPath);
+        } else {
+            rootDirPathTextView.setText("Not selected");
+        }
     }
 
     private void setupListeners() {
         startButton.setOnClickListener(v -> startFTPServer());
         stopButton.setOnClickListener(v -> stopFTPServer());
+        selectDirButton.setOnClickListener(v -> selectDirectory());
+        saveSettingsButton.setOnClickListener(v -> saveSettings());
+    }
+
+    private void selectDirectory() {
+        directoryPickerLauncher.launch(null);
+    }
+
+    private void saveSettings() {
+        String portStr = portEditText.getText().toString().trim();
+        if (portStr.isEmpty()) {
+            Toast.makeText(this, "Please enter a port number", Toast.LENGTH_SHORT).show();
+            return;
+        }
+
+        int port;
+        try {
+            port = Integer.parseInt(portStr);
+            if (port < 1024 || port > 65535) {
+                Toast.makeText(this, "Port must be between 1024 and 65535", Toast.LENGTH_SHORT).show();
+                return;
+            }
+        } catch (NumberFormatException e) {
+            Toast.makeText(this, "Invalid port number", Toast.LENGTH_SHORT).show();
+            return;
+        }
+
+        if (!config.hasRootDirectory()) {
+            Toast.makeText(this, "Please select a root directory", Toast.LENGTH_SHORT).show();
+            return;
+        }
+
+        config.setPort(port);
+        portTextView.setText("Port: " + port);
+
+        Toast.makeText(this, "Settings saved", Toast.LENGTH_SHORT).show();
     }
 
     private void requestPermissions() {
@@ -72,8 +172,15 @@ public class MainActivity extends AppCompatActivity {
     }
 
     private void startFTPServer() {
+        if (!config.hasRootDirectory()) {
+            Toast.makeText(this, "Please select a root directory first", Toast.LENGTH_LONG).show();
+            return;
+        }
+
         Intent serviceIntent = new Intent(this, FTPService.class);
         serviceIntent.setAction(FTPService.ACTION_START);
+        serviceIntent.putExtra("port", config.getPort());
+        serviceIntent.putExtra("rootDir", config.getRootDirectoryPath());
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             startForegroundService(serviceIntent);
@@ -83,7 +190,7 @@ public class MainActivity extends AppCompatActivity {
 
         isServerRunning = true;
         updateUI();
-        Toast.makeText(this, "FTP Server Started", Toast.LENGTH_SHORT).show();
+        Toast.makeText(this, "FTP Server Started on port " + config.getPort(), Toast.LENGTH_SHORT).show();
     }
 
     private void stopFTPServer() {

app/src/main/res/layout/activity_main.xml

@@ -1,12 +1,16 @@
 <?xml version="1.0" encoding="utf-8"?>
-<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<ScrollView 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:padding="16dp"
     tools:context=".MainActivity">
 
+<androidx.constraintlayout.widget.ConstraintLayout
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:padding="16dp">
+
     <TextView
         android:id="@+id/titleTextView"
         android:layout_width="wrap_content"
@@ -64,4 +68,92 @@
         app:layout_constraintTop_toBottomOf="@id/startButton"
         android:layout_marginTop="16dp" />
 
-</androidx.constraintlayout.widget.ConstraintLayout>
+    <View
+        android:id="@+id/divider"
+        android:layout_width="match_parent"
+        android:layout_height="1dp"
+        android:background="#CCCCCC"
+        android:layout_marginTop="32dp"
+        app:layout_constraintTop_toBottomOf="@id/stopButton"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintEnd_toEndOf="parent" />
+
+    <TextView
+        android:id="@+id/settingsTitle"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Settings"
+        android:textSize="20sp"
+        android:textStyle="bold"
+        android:layout_marginTop="24dp"
+        app:layout_constraintTop_toBottomOf="@id/divider"
+        app:layout_constraintStart_toStartOf="parent" />
+
+    <TextView
+        android:id="@+id/portLabel"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Port:"
+        android:textSize="16sp"
+        android:layout_marginTop="24dp"
+        app:layout_constraintTop_toBottomOf="@id/settingsTitle"
+        app:layout_constraintStart_toStartOf="parent" />
+
+    <EditText
+        android:id="@+id/portEditText"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:inputType="number"
+        android:hint="2121"
+        android:layout_marginStart="16dp"
+        app:layout_constraintBaseline_toBaselineOf="@id/portLabel"
+        app:layout_constraintStart_toEndOf="@id/portLabel"
+        app:layout_constraintEnd_toEndOf="parent" />
+
+    <TextView
+        android:id="@+id/rootDirLabel"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Root Directory:"
+        android:textSize="16sp"
+        android:layout_marginTop="16dp"
+        app:layout_constraintTop_toBottomOf="@id/portLabel"
+        app:layout_constraintStart_toStartOf="parent" />
+
+    <TextView
+        android:id="@+id/rootDirPathTextView"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:text="Not selected"
+        android:textSize="14sp"
+        android:layout_marginTop="8dp"
+        android:padding="8dp"
+        android:background="@android:color/darker_gray"
+        android:ellipsize="start"
+        android:singleLine="true"
+        app:layout_constraintTop_toBottomOf="@id/rootDirLabel"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintEnd_toEndOf="parent" />
+
+    <Button
+        android:id="@+id/selectDirButton"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Select Directory"
+        android:layout_marginTop="8dp"
+        app:layout_constraintTop_toBottomOf="@id/rootDirPathTextView"
+        app:layout_constraintStart_toStartOf="parent" />
+
+    <Button
+        android:id="@+id/saveSettingsButton"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Save Settings"
+        android:minWidth="150dp"
+        android:layout_marginTop="24dp"
+        app:layout_constraintTop_toBottomOf="@id/selectDirButton"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintEnd_toEndOf="parent" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>
+</ScrollView>