feat: 파일 목록 정렬 기능 추가 (이름순)

app/src/main/java/be/gyu/android/file/explorer/FileItem.java

@@ -1,6 +1,6 @@
 package be.gyu.android.file.explorer;
 
-public class FileItem {
+public class FileItem implements Comparable<FileItem> {
     private String name;
     private String path;
     private boolean isDirectory;
@@ -22,4 +22,16 @@ public class FileItem {
     public boolean isDirectory() {
         return isDirectory;
     }
+
+    @Override
+    public int compareTo(FileItem other) {
+        // Directories first
+        if (this.isDirectory() && !other.isDirectory()) {
+            return -1;
+        } else if (!this.isDirectory() && other.isDirectory()) {
+            return 1;
+        }
+        // Then sort by name, case-insensitively
+        return this.name.compareToIgnoreCase(other.name);
+    }
 }

app/src/main/java/be/gyu/android/file/explorer/MainActivity.java

@@ -32,6 +32,7 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 public class MainActivity extends AppCompatActivity implements FileAdapter.OnItemClickListener {
@@ -113,6 +114,7 @@ public class MainActivity extends AppCompatActivity implements FileAdapter.OnIte
                         String fullPath = path.equals("/") ? "/" + file.getName() : path + "/" + file.getName();
                         fileList.add(new FileItem(file.getName(), fullPath, file.isDirectory()));
                     }
+                    Collections.sort(fileList);
                 } else {
                      Toast.makeText(this, "Cannot read this directory!", Toast.LENGTH_SHORT).show();
                 }
@@ -154,6 +156,7 @@ public class MainActivity extends AppCompatActivity implements FileAdapter.OnIte
                 for (File file : files) {
                     fileList.add(new FileItem(file.getName(), file.getAbsolutePath(), file.isDirectory()));
                 }
+                Collections.sort(fileList);
             } else {
                 Toast.makeText(this, "Cannot read this directory!", Toast.LENGTH_SHORT).show();
             }