Refactor theme files comparision rule

src/main/java/run/halo/app/model/support/ThemeFile.java

@@ -3,6 +3,7 @@ package run.halo.app.model.support;
 import lombok.Data;
 import lombok.ToString;
 
+import java.util.Comparator;
 import java.util.List;
 
 /**
@@ -13,7 +14,7 @@ import java.util.List;
  */
 @Data
 @ToString
-public class ThemeFile {
+public class ThemeFile implements Comparator<ThemeFile> {
 
     private String name;
 
@@ -24,4 +25,17 @@ public class ThemeFile {
     private Boolean editable;
 
     private List<ThemeFile> node;
+
+    @Override
+    public int compare(ThemeFile leftFile, ThemeFile rightFile) {
+        if (leftFile.isFile && !rightFile.isFile) {
+            return 1;
+        }
+
+        if (!leftFile.isFile && rightFile.isFile) {
+            return -1;
+        }
+
+        return leftFile.getName().compareTo(rightFile.getName());
+    }
 }

src/main/java/run/halo/app/service/impl/ThemeServiceImpl.java

@@ -343,7 +343,7 @@ public class ThemeServiceImpl implements ThemeService {
             });
 
             // Sort with isFile param
-            themeFiles.sort(Comparator.comparing(ThemeFile::getIsFile));
+            themeFiles.sort(new ThemeFile());
 
             return themeFiles;
         } catch (IOException e) {