debug(file): 添加文件下载功能的调试日志

- 在 FileSDK 的 saveBlobDownload 方法中添加解码、目录创建和文件写入的日志记录
- 在 XWebViewView 的 readBlobAndPost 函数中添加 JavaScript 端的数据读取和错误处理日志
- 添加锚点拦截和消息传递过程中的日志记录
- 在 blobdownload 处理流程中添加成功和失败的状态日志
- 增加文件保存到相册操作的结果日志记录

sdk-core/src/main/java/com/xuqm/sdk/file/FileSDK.kt

@@ -251,7 +251,9 @@ object FileSDK {
         fileName: String,
         destination: FileDownloadDestination = FileDownloadDestination.Sandbox,
     ): File {
+        android.util.Log.d("XWV", "saveBlobDownload: fileName=$fileName, dest=$destination, b64Len=${base64Data.length}")
         val bytes = android.util.Base64.decode(base64Data, android.util.Base64.DEFAULT)
+        android.util.Log.d("XWV", "saveBlobDownload: decoded ${bytes.size} bytes")
         val baseDir = when (destination) {
             FileDownloadDestination.PublicDownloads -> {
                 val appName = context.applicationInfo.loadLabel(context.packageManager).toString()
@@ -260,14 +262,21 @@ object FileSDK {
                         android.os.Environment.DIRECTORY_DOWNLOADS
                     ),
                     appName,
-                ).apply { mkdirs() }
+                ).apply {
+                    val created = mkdirs()
+                    android.util.Log.d("XWV", "saveBlobDownload: PublicDownloads dir=$absolutePath, created=$created, exists=${exists()}")
+                }
             }
             FileDownloadDestination.Sandbox -> {
-                context.getExternalFilesDir(null) ?: context.filesDir
+                (context.getExternalFilesDir(null) ?: context.filesDir).also {
+                    android.util.Log.d("XWV", "saveBlobDownload: Sandbox dir=${it.absolutePath}")
+                }
             }
         }
         val target = uniqueFile(baseDir, fileName.takeIf { it.isNotBlank() } ?: "download.bin")
+        android.util.Log.d("XWV", "saveBlobDownload: writing to ${target.absolutePath}")
         target.writeBytes(bytes)
+        android.util.Log.d("XWV", "saveBlobDownload: done, size=${target.length()}")
         return target
     }
 

sdk-webview/src/main/java/com/xuqm/sdk/webview/XWebViewView.kt

@@ -100,17 +100,29 @@ internal fun buildDialogOverrideJs(bridgeName: String) = """
   URL.revokeObjectURL = function() {};
 
   function readBlobAndPost(blobUrl, filename) {
+    console.log('[XWV] readBlobAndPost start, url=' + blobUrl + ', filename=' + filename);
     fetch(blobUrl)
-      .then(function(r) { return r.blob(); })
+      .then(function(r) {
+        console.log('[XWV] fetch ok, size=' + r.size);
+        return r.blob();
+      })
       .then(function(blob) {
+        console.log('[XWV] blob ok, size=' + blob.size + ', type=' + blob.type);
         var reader = new FileReader();
         reader.onloadend = function() {
           var b64 = reader.result.split(',')[1];
+          console.log('[XWV] base64 ready, len=' + (b64 ? b64.length : 0));
           post({ __xwv: 'blobdownload', url: blobUrl, filename: filename, data: b64 });
+          console.log('[XWV] blobdownload posted');
+        };
+        reader.onerror = function(e) {
+          console.log('[XWV] FileReader error: ' + String(e));
+          post({ __xwv: 'bloberror', msg: 'FileReader error: ' + String(e) });
         };
         reader.readAsDataURL(blob);
       })
       .catch(function(err) {
+        console.log('[XWV] readBlobAndPost ERROR: ' + String(err));
         post({ __xwv: 'bloberror', msg: String(err) });
       });
   }
@@ -125,6 +137,7 @@ internal fun buildDialogOverrideJs(bridgeName: String) = """
     var hasDownloadAttr = el.hasAttribute('download');
     var dlName = el.getAttribute('download') || '';
     var isDL = hasDownloadAttr || dlRe.test(href);
+    console.log('[XWV] tryInterceptAnchor href=' + href + ', hasDownload=' + hasDownloadAttr + ', isDL=' + isDL);
     if (isDL) {
       if (e) { e.preventDefault(); e.stopPropagation(); }
       if (href.startsWith('blob:')) {
@@ -180,9 +193,11 @@ internal class XWebViewJsBridge(
 ) {
     @JavascriptInterface
     fun postMessage(data: String) {
+        android.util.Log.d("XWV", "postMessage: ${data.take(200)}")
         mainHandler.post {
             val json = runCatching { JSONObject(data) }.getOrNull()
             val xwv = json?.optString("__xwv")?.takeIf { it.isNotEmpty() }
+            android.util.Log.d("XWV", "postMessage parsed: xwv=$xwv")
             if (xwv != null && json != null) {
                 onXwvMessage()?.invoke(xwv, json)
             } else {
@@ -229,6 +244,7 @@ fun XWebViewView(
 
     // Handles __xwv: 'download' / 'blobdownload' messages from the injected JS.
     val xwvMessageHandler: (String, JSONObject) -> Unit = handler@{ type, payload ->
+        android.util.Log.d("XWV", "xwvMessage type=$type, payload=${payload.toString().take(200)}")
         when (type) {
             "download" -> {
                 val url = payload.optString("url").takeIf { it.isNotBlank() } ?: return@handler
@@ -267,19 +283,26 @@ fun XWebViewView(
             "blobdownload" -> {
                 val url = payload.optString("url")
                 val filename = payload.optString("filename").takeIf { it.isNotBlank() } ?: "download.bin"
-                val b64 = payload.optString("data").takeIf { it.isNotBlank() } ?: return@handler
+                val b64 = payload.optString("data").takeIf { it.isNotBlank() } ?: run {
+                    android.util.Log.e("XWV", "blobdownload: empty data")
+                    return@handler
+                }
+                android.util.Log.d("XWV", "blobdownload: filename=$filename, b64Len=${b64.length}, dest=${config.downloadDestination}")
                 coroutineScope.launch(Dispatchers.IO) {
                     runCatching {
                         FileSDK.saveBlobDownload(context, b64, filename, config.downloadDestination)
                     }.onSuccess { file ->
+                        android.util.Log.d("XWV", "blobdownload saved: ${file.absolutePath}, size=${file.length()}")
                         // For image files, save to the system gallery (相册) so they appear in Photos
                         val savedToGallery = runCatching { FileSDK.saveImageToGallery(context, file) }.getOrDefault(false)
+                        android.util.Log.d("XWV", "blobdownload savedToGallery=$savedToGallery")
                         withContext(Dispatchers.Main) {
                             dispatchDownloadEvent("__xwvDownloadDone", url, ",success:true")
                             // Only open with file viewer when not saved to gallery (e.g. zip, docx)
                             if (!savedToGallery) FileSDK.openFile(context, file)
                         }
                     }.onFailure { e ->
+                        android.util.Log.e("XWV", "blobdownload FAILED", e)
                         withContext(Dispatchers.Main) {
                             dispatchDownloadEvent("__xwvDownloadDone", url, ",success:false,error:'${e.message?.escapeJs()}'")
                         }