修复一处字段读取错误

usr/lib/sonist/window.py

@@ -317,11 +317,10 @@ class SonistWindow(Gtk.Window):
         # 更新歌曲信息
         self.title_box.update(f"{song.get('artist')} - {song.get('title')}")
 
-        title = song.get('title')
-        title_hex = base64.b64encode(title.encode()).hex()
+        title_hex = base64.b64encode(song.get('title').encode()).hex()
 
         filepath = f"{self.app.album_cache_dir}/{title_hex}.png"
-        songpath = f"{self.app.music_dir}/{title}"
+        songpath = f"{self.app.music_dir}/{song.get('file')}"
 
         if os.path.isfile(filepath):
           self.update_album(filepath)