fix: 兼容性问题

app.json

@@ -21,7 +21,7 @@
       "edgeToEdgeEnabled": true,
       "predictiveBackGestureEnabled": false,
       "package": "com.anonymous.bwexpoappv3",
-      "versionCode": 3
+      "versionCode": 4
     },
     "web": {
       "output": "static",

app/result.tsx

@@ -1,7 +1,7 @@
 import { ThemedView } from '@/components/themed-view';
 import { getTemplateGeneration } from '@/lib/api/template-runs';
 import * as Clipboard from 'expo-clipboard';
-import * as FileSystem from 'expo-file-system';
+import { documentDirectory, downloadAsync } from 'expo-file-system/legacy';
 import * as MediaLibrary from 'expo-media-library';
 import { router, useLocalSearchParams } from 'expo-router';
 import { VideoView, useVideoPlayer } from 'expo-video';
@@ -85,6 +85,14 @@ function getMediaType(url: string): 'image' | 'video' | 'unknown' {
   return 'unknown';
 }
 
+/**
+ * 安全获取媒体类型，过滤掉 unknown
+ */
+function getSafeMediaType(url: string): 'image' | 'video' {
+  const type = getMediaType(url);
+  return type === 'unknown' ? 'image' : type;
+}
+
 export default function ResultPage() {
   const { generationId } = useLocalSearchParams<{ generationId: string }>();
   const insets = useSafeAreaInsets();
@@ -194,11 +202,17 @@ export default function ResultPage() {
         try {
           // 生成临时文件名
           const filename = url.split('/').pop() || `download_${Date.now()}`;
-          const fileUri = `${FileSystem.documentDirectory}${filename}`;
+
+          if (!documentDirectory) {
+            console.error('Document directory not available');
+            continue;
+          }
+
+          const fileUri = `${documentDirectory}${filename}`;
 
           // 下载文件到本地
           console.log('Downloading:', url, 'to', fileUri);
-          const downloadResult = await FileSystem.downloadAsync(url, fileUri);
+          const downloadResult = await downloadAsync(url, fileUri);
 
           if (downloadResult.status === 200) {
             // 保存到相册
@@ -402,7 +416,7 @@ export default function ResultPage() {
               style={styles.expandButton}
               onPress={() =>
                 openFullscreen(
-                  getMediaType(mediaUrls[currentMediaIndex]),
+                  getSafeMediaType(mediaUrls[currentMediaIndex]),
                   mediaUrls[currentMediaIndex]
                 )
               }