修复缺失的dir_name设置；使用多线程获取版本列表

Author: Zhao Zuohong

main.py

@@ -22,7 +22,8 @@
         "screenshot/**/*",
         "adb-buildin/*",
     ],
-    "install_dir": "",
+    "install_dir": "请选择",
+    "dir_name": "mower",
     "pool_limit": 16,
 }
 
@@ -47,7 +48,7 @@
     ],
     [
         sg.vtop(sg.Text("版本：", size=(10, 1))),
-        sg.Listbox([], key="versions", size=(60, 6)),
+        sg.Listbox(["按“刷新”按钮获取版本列表"], key="versions", size=(60, 6)),
     ],
     [
         sg.Text("安装位置：", size=(10, 1)),
@@ -100,21 +101,27 @@ def connect_mirror(mirror):
 def fetch_version_details(mirror, versions):
     if not mirror.endswith("/"):
         mirror += "/"
+
     result = []
-    for v in versions:
+
+    def fetch_single_version_detail(v):
         url = mirror + v + "/version.json"
         try:
             r = s.get(url)
             pub_time = r.json()["time"]
         except Exception:
-            continue
-        result.append(
-            {
-                "version": v,
-                "display_name": f"{v} ({pub_time})",
-                "hash": r.json()["hash"],
-            }
-        )
+            return None
+        return {
+            "version": v,
+            "display_name": f"{v} ({pub_time})",
+            "hash": r.json()["hash"],
+        }
+
+    with ThreadPool(conf["pool_limit"]) as pool:
+        for info in pool.imap(fetch_single_version_detail, versions):
+            if info:
+                result.append(info)
+
     return result