fixed broken creation of new subjects

Author: litoj

Android app/app/build.gradle

@@ -7,8 +7,8 @@ android {
         applicationId "com.schlmgr"
         minSdkVersion 19
         targetSdkVersion 32
-        versionCode 60
-        versionName '1.8.1'
+        versionCode 61
+        versionName '1.8.2'
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         signingConfig signingConfigs.debug
     }

Android app/app/src/main/java/com/schlmgr/gui/UriPath.java

@@ -129,7 +129,7 @@ protected boolean deleteFile(DocumentFile src) {
 
 	@Override
 	public boolean exists() {
-		return file.exists();
+		return file.exists() && (file.isDirectory() || file.length() > 0);
 	}
 
 	@Override