优化扫描方法：

1.分快速扫描与全盘扫描
2.下拉刷新必定调用全扫
3.每次重新创建应用则进行全盘扫描
4.每次只进入onResume则进行快速扫描

app/src/main/java/com/all/pdfreader/pro/app/PDFReaderApplication.kt

@@ -11,6 +11,8 @@ class PDFReaderApplication : Application() {
         private lateinit var instance: PDFReaderApplication
         fun getInstance(): PDFReaderApplication = instance
         fun getContext(): Context = instance.applicationContext
+        //是新创建了界面，则需要全盘扫描，进入onResume判定，扫描方法调用后置为false
+        var isNeedFullScan = false
     }
 
     private lateinit var fileChangeObserver: FileChangeObserver
@@ -18,7 +20,7 @@ class PDFReaderApplication : Application() {
     override fun onCreate() {
         super.onCreate()
         instance = this
-
+        isNeedFullScan = true
         // 初始化文件变化监听（不立即启动）
         fileChangeObserver = FileChangeObserver(this)
 

app/src/main/java/com/all/pdfreader/pro/app/ui/act/MainActivity.kt

@@ -158,20 +158,28 @@ class MainActivity : BaseActivity(), PermissionDialogFragment.PermissionCallback
     }
 
     private fun scanningStrategy() {
-        // 智能扫描策略
+        if (StoragePermissionHelper.hasBasicStoragePermission(this)) {
-        if (pdfScanner.shouldScan()) {
+            lifecycleScope.launch {
-            logDebug("🔄 需要扫描PDF文件 (首次启动或超过24小时)")
+                pdfScanner.scanAndLoadPdfFiles(PDFReaderApplication.isNeedFullScan)
-            if (StoragePermissionHelper.hasBasicStoragePermission(this)) {
-                lifecycleScope.launch {
-                    pdfScanner.scanAndLoadPdfFiles()
-                }
-            } else {
-                logDebug("❌ 权限不足，跳过扫描")
             }
         } else {
-            val hoursAgo = pdfScanner.getHoursSinceLastScan()
+            logDebug("❌ 权限不足，跳过扫描")
-            logDebug("⏭️ 跳过扫描，上次扫描在${hoursAgo}小时前")
         }
+
+//        // 智能扫描策略
+//        if (pdfScanner.shouldScan()) {
+//            logDebug("🔄 需要扫描PDF文件 (首次启动或超过24小时)")
+//            if (StoragePermissionHelper.hasBasicStoragePermission(this)) {
+//                lifecycleScope.launch {
+//                    pdfScanner.scanAndLoadPdfFiles()
+//                }
+//            } else {
+//                logDebug("❌ 权限不足，跳过扫描")
+//            }
+//        } else {
+//            val hoursAgo = pdfScanner.getHoursSinceLastScan()
+//            logDebug("⏭️ 跳过扫描，上次扫描在${hoursAgo}小时前")
+//        }
     }
 
     // 授权后续操作

app/src/main/java/com/all/pdfreader/pro/app/ui/fragment/HomeFrag.kt

@@ -52,7 +52,7 @@ class HomeFrag : BaseFrag(), MainActivity.SortableFragment {
         binding.swipeRefreshLayout.setOnRefreshListener {
             lifecycleScope.launch {
                 val pdfScanner = PdfScanner(requireContext(), getRepository())
-                pdfScanner.scanAndLoadPdfFiles { b ->
+                pdfScanner.scanAndLoadPdfFiles(true) { b ->
                     binding.swipeRefreshLayout.isRefreshing = false
                 }
             }

app/src/main/java/com/all/pdfreader/pro/app/util/FileChangeObserver.kt

@@ -8,11 +8,14 @@ import android.os.Looper
 import android.provider.MediaStore
 import android.util.Log
 import androidx.lifecycle.LifecycleObserver
+import com.all.pdfreader.pro.app.room.repository.PdfRepository
+import com.all.pdfreader.pro.app.util.FileUtils.getFileFromUri
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
+import java.io.File
 
 class FileChangeObserver(
     private val context: Context,
@@ -32,7 +35,15 @@ class FileChangeObserver(
         contentObserver = object : ContentObserver(Handler(Looper.getMainLooper())) {
             override fun onChange(selfChange: Boolean, uri: Uri?) {
                 super.onChange(selfChange, uri)
-                handleFileChange()
+                if (uri != null) {
+                    val file = getFileFromUri(context, uri)
+                    if (file != null) {
+                        Log.d("ocean", "修改的文件: ${file.absolutePath}")
+                        // 可以传给你的增量扫描逻辑
+
+                        handleFileChange(file)
+                    }
+                }
             }
         }
 
@@ -63,7 +74,7 @@ class FileChangeObserver(
         }
     }
 
-    private fun handleFileChange() {
+    private fun handleFileChange(file: File) {
         val currentTime = System.currentTimeMillis()
         if (currentTime - lastScanTime < debounceDelay) {
             return // 防抖
@@ -76,7 +87,18 @@ class FileChangeObserver(
 
             if (StoragePermissionHelper.hasBasicStoragePermission(context)) {
                 Log.d("ocean", "📂 检测到文件变化，可以执行增量扫描...")
-
+                val pdfRepository = PdfRepository.getInstance()
+                val existingDoc = pdfRepository.getDocumentByPath(file.absolutePath)
+                if (existingDoc != null) {
+                    LogUtil.logDebug(
+                        "ocean",
+                        "PdfScanner:    📖 ${existingDoc.fileName} - ${existingDoc.pageCount}页 - ${
+                            FileUtils.formatFileSize(
+                                existingDoc.fileSize
+                            )
+                        } - ${existingDoc.thumbnailPath}"
+                    )
+                }
             }
         }
     }

app/src/main/java/com/all/pdfreader/pro/app/util/FileUtils.kt

@@ -344,4 +344,35 @@ object FileUtils {
             } catch (_: Exception) {}
         }
     }
+
+    fun getFileFromUri(context: Context, uri: Uri): File? {
+        // 先尝试通过 DATA 字段获取
+        val projection = arrayOf(MediaStore.Files.FileColumns.DATA)
+        context.contentResolver.query(uri, projection, null, null, null)?.use { cursor ->
+            if (cursor.moveToFirst()) {
+                val path = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Files.FileColumns.DATA))
+                if (!path.isNullOrEmpty()) {
+                    val file = File(path)
+                    if (file.exists()) {
+                        return file
+                    }
+                }
+            }
+        }
+
+        // Android 10+ 或 DATA 字段为空时，使用 ContentResolver 流访问
+        return try {
+            val tempFile = File(context.cacheDir, "temp_pdf_${System.currentTimeMillis()}.pdf")
+            context.contentResolver.openInputStream(uri)?.use { input ->
+                tempFile.outputStream().use { output ->
+                    input.copyTo(output)
+                }
+            }
+            tempFile
+        } catch (e: Exception) {
+            Log.e("ocean", "无法获取文件: ${e.message}", e)
+            null
+        }
+    }
+
 }

app/src/main/java/com/all/pdfreader/pro/app/util/PdfScanner.kt

@@ -8,6 +8,7 @@ import android.graphics.pdf.PdfRenderer
 import android.os.ParcelFileDescriptor
 import android.util.Log
 import androidx.core.graphics.createBitmap
+import com.all.pdfreader.pro.app.PDFReaderApplication
 import com.all.pdfreader.pro.app.room.entity.PdfDocumentEntity
 import com.all.pdfreader.pro.app.room.repository.PdfRepository
 import com.all.pdfreader.pro.app.util.FileUtils.isPdfEncrypted
@@ -23,167 +24,208 @@ class PdfScanner(
 
     private val TAG = "ocean-PdfScanner"
 
-    suspend fun scanAndLoadPdfFiles(callback: (Boolean) -> Unit = {}) {
+    suspend fun scanAndLoadPdfFiles(isNeedFullScan: Boolean, callback: (Boolean) -> Unit = {}) {
         if (!StoragePermissionHelper.hasBasicStoragePermission(context)) {
-            LogUtil.logDebug(TAG, "PdfScanner: 权限不足")
+            LogUtil.logDebug(TAG, "权限不足")
             callback.invoke(false)
             return
         }
 
         withContext(Dispatchers.IO) {
             try {
-                LogUtil.logDebug(TAG, "PdfScanner: 🔍 开始扫描PDF文件...")
+                val startScannerTime = System.currentTimeMillis()
-
+                LogUtil.logDebug(TAG, "🔍开始扫描PDF文件...")
-                // 扫描应用私有目录（无需权限）
+                LogUtil.logDebug(TAG, "获取数据库数据")
-                val privateFiles = FileUtils.scanPdfFiles(context)
+                val cachedDocs = pdfRepository.getAllDocumentsOnce()
-                LogUtil.logDebug(
+                var needFullScan = isNeedFullScan
-                    TAG, "PdfScanner: 📁 应用私有目录找到: ${privateFiles.size} 个PDF文件"
+                if (!needFullScan) {
-                )
+                    cachedDocs.forEach { doc ->
-                privateFiles.forEach { file ->
+                        val file = File(doc.filePath)//得到数据库存储的文件路径
-                    LogUtil.logDebug(
+                        if (file.exists()) {
-                        TAG,
+                            LogUtil.logDebug(TAG, "$file 文件存在，检测是否存在变化")
-                        "PdfScanner:    📄 ${file.name} (${FileUtils.formatFileSize(file.length())})"
+                            var needUpdate = false
-                    )
+                            var updatedDoc = doc.copy()
-                }
+                            // 修改时间 与 文件大小
-
+                            if (file.lastModified() != doc.lastModified || file.length() != doc.fileSize) {
-                // 扫描MediaStore（需要权限）
+                                LogUtil.logDebug(TAG, "文件时间或者大小被修改 -> ${doc.fileName}")
-                val mediaStoreFiles = FileUtils.scanPdfFilesFromMediaStore(context)
+                                updatedDoc = updatedDoc.copy(
-                LogUtil.logDebug(
-                    TAG, "PdfScanner: 📱 MediaStore找到: ${mediaStoreFiles.size} 个PDF文件"
-                )
-                mediaStoreFiles.forEach { file ->
-                    LogUtil.logDebug(
-                        TAG,
-                        "PdfScanner:    📱 ${file.name} (${FileUtils.formatFileSize(file.length())})"
-                    )
-                }
-
-                // 合并并去重
-                val allFiles = (privateFiles + mediaStoreFiles).distinctBy { it.absolutePath }
-                LogUtil.logDebug(TAG, "PdfScanner: 📊 总计扫描到: ${allFiles.size} 个PDF文件")
-
-                // 处理每个PDF文件
-                allFiles.forEachIndexed { index, file ->
-                    LogUtil.logDebug(
-                        TAG,
-                        "PdfScanner: 🔄 处理文件 ${index + 1}/${allFiles.size}: ${file.name} - ${file.absolutePath}"
-                    )
-
-                    if (FileUtils.isPdfFile(file)) {
-                        val fileHash = FileUtils.calculateFileHash(file.absolutePath)
-                        LogUtil.logDebug(TAG, "PdfScanner:    🔑 文件哈希: $fileHash")
-
-                        if (fileHash != null) {
-                            val existingDoc = pdfRepository.getDocumentByPath(file.absolutePath)
-
-                            if (existingDoc == null) {
-                                LogUtil.logDebug(
-                                    TAG, "PdfScanner:    🆕 发现新PDF文件: ${file.name}"
-                                )
-                                var thumbnailPath: String? = null
-                                val isPassword = isPdfEncrypted(file)
-                                LogUtil.logDebug(TAG, "PdfScanner: isPassword->${isPassword}")
-                                if (!isPassword) {//没有密码的情况下才去获取缩略图
-                                    thumbnailPath = generateThumbnail(context, file) ?: ""
-                                }
-                                LogUtil.logDebug(TAG, "PdfScanner: thumbnailPath->${thumbnailPath}")
-                                val metadata =
-                                    PdfMetadataExtractor.extractMetadata(file.absolutePath)
-                                val document = PdfDocumentEntity(
-                                    fileHash = fileHash,
-                                    filePath = file.absolutePath,
-                                    fileName = file.name,
-                                    fileSize = file.length(),
                                     lastModified = file.lastModified(),
-                                    pageCount = metadata?.pageCount ?: 0,
+                                    fileSize = file.length()
-                                    thumbnailPath = thumbnailPath,
-                                    metadataTitle = metadata?.title,
-                                    metadataAuthor = metadata?.author,
-                                    metadataSubject = metadata?.subject,
-                                    metadataKeywords = metadata?.keywords,
-                                    metadataCreationDate = metadata?.creationDate?.time,
-                                    metadataModificationDate = metadata?.modificationDate?.time,
-                                    isPassword = isPassword
                                 )
-                                pdfRepository.insertOrUpdateDocument(document)
+                                needUpdate = true
-                                LogUtil.logDebug(
+                            }
-                                    TAG, "PdfScanner:    ✅ 已保存到数据库: ${file.name}"
+                            if (needUpdate) {
-                                )
+                                // 是否加密
-                            } else {
-                                LogUtil.logDebug(TAG, "PdfScanner:  📋 文件已存在: ${file.name}")
-                                // 🔹 文件已存在，检查是否需要更新
-                                var needUpdate = false
-                                var updatedDoc = existingDoc.copy()
-
-                                // 路径/修改时间更新
-                                if (existingDoc.filePath != file.absolutePath || existingDoc.lastModified != file.lastModified()) {
-                                    LogUtil.logDebug(TAG, "PdfScanner: ✅ 路径/修改时间需要更新")
-                                    updatedDoc = updatedDoc.copy(
-                                        filePath = file.absolutePath,
-                                        lastModified = file.lastModified()
-                                    )
-                                    needUpdate = true
-                                }
-
-                                // 是否加密更新
                                 val currentIsPassword = isPdfEncrypted(file)
-                                if (existingDoc.isPassword != currentIsPassword) {
+                                if (doc.isPassword != currentIsPassword) {
-                                    LogUtil.logDebug(TAG, "PdfScanner: ✅ 密码状态需要更新")
+                                    LogUtil.logDebug(TAG, "密码状态变化 -> ${doc.fileName}")
                                     updatedDoc = updatedDoc.copy(isPassword = currentIsPassword)
-                                    needUpdate = true
                                 }
-
+                                // 缩略图（仅非加密文件）
                                 if (!currentIsPassword) {
-                                    // 如果不是加密 PDF，再生成缩略图
                                     val newThumbnail = generateThumbnail(context, file)
-                                    if (existingDoc.thumbnailPath != newThumbnail) {
+                                    if (doc.thumbnailPath != newThumbnail) {
-                                        LogUtil.logDebug(TAG, "PdfScanner: ✅ 缩略图需要更新")
                                         updatedDoc = updatedDoc.copy(thumbnailPath = newThumbnail)
+                                    }
+                                } else if (doc.thumbnailPath != null) {
+                                    updatedDoc = updatedDoc.copy(thumbnailPath = null)
+                                }
+                                pdfRepository.insertOrUpdateDocument(updatedDoc)
+                                LogUtil.logDebug(TAG, "✅数据库已更新: ${doc.fileName}")
+                            }
+                        } else {
+                            // 文件不存在 → 删除数据库记录，并触发全盘扫描
+                            LogUtil.logDebug(TAG, "文件不存在 -> ${doc.fileName}, 删除记录")
+                            pdfRepository.deleteDocument(doc.fileHash)
+                            needFullScan = true
+                        }
+                    }
+                }
+                if (needFullScan || cachedDocs.isEmpty()) {
+                    LogUtil.logDebug(TAG, "数据库不完整，执行全盘扫描...")
+                    // 扫描应用私有目录（无需权限）
+                    val privateFiles = FileUtils.scanPdfFiles(context)
+                    LogUtil.logDebug(TAG, "📁应用私有目录找到: ${privateFiles.size} 个PDF文件")
+                    // 扫描MediaStore（需要权限）
+                    val mediaStoreFiles = FileUtils.scanPdfFilesFromMediaStore(context)
+                    LogUtil.logDebug(TAG, "📱MediaStore找到: ${mediaStoreFiles.size} 个PDF文件")
+                    // 合并并去重
+                    val allFiles = (privateFiles + mediaStoreFiles).distinctBy { it.absolutePath }
+                    LogUtil.logDebug(TAG, "📊总计扫描到: ${allFiles.size} 个PDF文件")
+                    // 处理每个PDF文件
+                    allFiles.forEachIndexed { index, file ->
+                        LogUtil.logDebug(
+                            TAG,
+                            "🔄处理文件 ${index + 1}/${allFiles.size}: ${file.name} - ${file.absolutePath}"
+                        )
+
+                        if (FileUtils.isPdfFile(file)) {
+                            val fileHash = FileUtils.calculateFileHash(file.absolutePath)
+                            LogUtil.logDebug(TAG, "🔑文件哈希: $fileHash")
+
+                            if (fileHash != null) {
+                                val existingDoc = pdfRepository.getDocumentByPath(file.absolutePath)
+
+                                if (existingDoc == null) {
+                                    LogUtil.logDebug(
+                                        TAG, "🆕发现新PDF文件: ${file.name}"
+                                    )
+                                    var thumbnailPath: String? = null
+                                    val isPassword = isPdfEncrypted(file)
+                                    LogUtil.logDebug(TAG, "isPassword->${isPassword}")
+                                    if (!isPassword) {//没有密码的情况下才去获取缩略图
+                                        thumbnailPath = generateThumbnail(context, file) ?: ""
+                                    }
+                                    LogUtil.logDebug(TAG, "thumbnailPath->${thumbnailPath}")
+                                    val metadata =
+                                        PdfMetadataExtractor.extractMetadata(file.absolutePath)
+                                    val document = PdfDocumentEntity(
+                                        fileHash = fileHash,
+                                        filePath = file.absolutePath,
+                                        fileName = file.name,
+                                        fileSize = file.length(),
+                                        lastModified = file.lastModified(),
+                                        pageCount = metadata?.pageCount ?: 0,
+                                        thumbnailPath = thumbnailPath,
+                                        metadataTitle = metadata?.title,
+                                        metadataAuthor = metadata?.author,
+                                        metadataSubject = metadata?.subject,
+                                        metadataKeywords = metadata?.keywords,
+                                        metadataCreationDate = metadata?.creationDate?.time,
+                                        metadataModificationDate = metadata?.modificationDate?.time,
+                                        isPassword = isPassword
+                                    )
+                                    pdfRepository.insertOrUpdateDocument(document)
+                                    LogUtil.logDebug(
+                                        TAG, "    ✅ 已保存到数据库: ${file.name}"
+                                    )
+                                } else {
+                                    LogUtil.logDebug(TAG, "  📋 文件已存在: ${file.name}")
+                                    // 🔹 文件已存在，检查是否需要更新
+                                    var needUpdate = false
+                                    var updatedDoc = existingDoc.copy()
+
+                                    // 路径/修改时间更新
+                                    if (existingDoc.filePath != file.absolutePath || existingDoc.lastModified != file.lastModified()) {
+                                        LogUtil.logDebug(TAG, "✅ 路径/修改时间需要更新")
+                                        updatedDoc = updatedDoc.copy(
+                                            filePath = file.absolutePath,
+                                            lastModified = file.lastModified()
+                                        )
                                         needUpdate = true
                                     }
-                                } else {
-                                    updatedDoc = updatedDoc.copy(thumbnailPath = null)
-                                    needUpdate = true
-                                }
 
-                                // 执行更新
+                                    // 是否加密更新
-                                if (needUpdate) {
+                                    val currentIsPassword = isPdfEncrypted(file)
-                                    pdfRepository.insertOrUpdateDocument(updatedDoc)
+                                    if (existingDoc.isPassword != currentIsPassword) {
-                                    LogUtil.logDebug(
+                                        LogUtil.logDebug(TAG, "✅ 密码状态需要更新")
-                                        TAG, "PdfScanner: ✅ 数据库已更新: ${file.name}"
+                                        updatedDoc = updatedDoc.copy(isPassword = currentIsPassword)
-                                    )
+                                        needUpdate = true
-                                } else {
+                                    }
-                                    LogUtil.logDebug(
+
-                                        TAG, "PdfScanner: ⏩ 无需更新: ${file.name}"
+                                    if (!currentIsPassword) {
-                                    )
+                                        // 如果不是加密 PDF，再生成缩略图
+                                        val newThumbnail = generateThumbnail(context, file)
+                                        if (existingDoc.thumbnailPath != newThumbnail) {
+                                            LogUtil.logDebug(TAG, "✅ 缩略图需要更新")
+                                            updatedDoc =
+                                                updatedDoc.copy(thumbnailPath = newThumbnail)
+                                            needUpdate = true
+                                        }
+                                    } else {
+                                        updatedDoc = updatedDoc.copy(thumbnailPath = null)
+                                        needUpdate = true
+                                    }
+
+                                    // 执行更新
+                                    if (needUpdate) {
+                                        pdfRepository.insertOrUpdateDocument(updatedDoc)
+                                        LogUtil.logDebug(
+                                            TAG, "✅ 数据库已更新: ${file.name}"
+                                        )
+                                    } else {
+                                        LogUtil.logDebug(
+                                            TAG, "⏩ 无需更新: ${file.name}"
+                                        )
+                                    }
                                 }
                             }
                         }
                     }
+                    // 打印数据库中的总记录数
+                    pdfRepository.getAllDocumentsOnce().forEach { doc ->
+                        LogUtil.logDebug(
+                            TAG, "    📖 ${doc.fileName} - ${doc.pageCount}页 - ${
+                                FileUtils.formatFileSize(
+                                    doc.fileSize
+                                )
+                            } - ${doc.thumbnailPath}"
+                        )
+                    }
                 }
-
-                // 打印数据库中的总记录数
-                pdfRepository.getAllDocumentsOnce().forEach { doc ->
-                    LogUtil.logDebug(
-                        TAG, "PdfScanner:    📖 ${doc.fileName} - ${doc.pageCount}页 - ${
-                            FileUtils.formatFileSize(
-                                doc.fileSize
-                            )
-                        } - ${doc.thumbnailPath}"
-                    )
-                }
-
                 // 标记扫描完成
                 ScanManager.markScanComplete(context)
                 val lastScanTime = ScanManager.getLastScanTime(context)
                 LogUtil.logDebug(
-                    TAG, "PdfScanner: ✅ 扫描完成，记录时间: ${java.util.Date(lastScanTime)}"
+                    TAG, "✅ 扫描完成，记录时间: ${java.util.Date(lastScanTime)}"
                 )
-
+                var string = if (needFullScan) {
+                    "全盘扫描"
+                } else if (cachedDocs.isEmpty()) {
+                    "数据库没有值，第一次全盘扫描"
+                } else {
+                    "快速扫描"
+                }
+                // 计算扫描耗时
+                val scannerTime = System.currentTimeMillis() - startScannerTime
+                LogUtil.logDebug(
+                    TAG,
+                    "$string 本次扫描耗时: $scannerTime ms (${scannerTime / 1000.0} 秒)"
+                )
+                PDFReaderApplication.isNeedFullScan = false
                 callback.invoke(true)
-
             } catch (e: Exception) {
-                Log.e(TAG, "PdfScanner: ❌ 扫描出错: ${e.message}", e)
+                Log.e(TAG, "❌ 扫描出错: ${e.message}", e)
                 callback.invoke(false)
             }
         }