添加批量操作等功能。

app/src/main/java/com/all/pdfreader/pro/app/model/FileActionEvent.kt

@@ -5,6 +5,9 @@ import java.io.File
 sealed class FileActionEvent {
     data class Rename(val renameResult: RenameResult) : FileActionEvent()
     data class Delete(val deleteResult: DeleteResult) : FileActionEvent()
+    data class DeleteAll(val status: Status, val deleteResult: DeleteResult? = null) : FileActionEvent() {
+        enum class Status { START, COMPLETE }
+    }
     data class Favorite(val isFavorite: Boolean) : FileActionEvent()
     data class Duplicate(val file: File?) : FileActionEvent()
 

app/src/main/java/com/all/pdfreader/pro/app/room/dao/BookmarkDao.kt

@@ -31,6 +31,9 @@ interface BookmarkDao {
     @Query("DELETE FROM bookmarks WHERE filePath = :filePath")
     suspend fun deleteAllByPdf(filePath: String): Int
 
+    @Query("DELETE FROM bookmarks WHERE filePath IN (:filePaths)")
+    suspend fun deleteAllByPdfs(filePaths: List<String>): Int
+
     @Query("DELETE FROM bookmarks WHERE filePath = :filePath AND pageNumber = :pageNumber")
     suspend fun deleteByPage(filePath: String, pageNumber: Int)
 

app/src/main/java/com/all/pdfreader/pro/app/room/dao/NoteDao.kt

@@ -34,6 +34,9 @@ interface NoteDao {
     @Query("DELETE FROM notes WHERE filePath = :filePath")
     suspend fun deleteAllByPdf(filePath: String)
 
+    @Query("DELETE FROM notes WHERE filePath IN (:filePaths)")
+    suspend fun deleteAllByPdfs(filePaths: List<String>)
+
     @Query("DELETE FROM notes WHERE filePath = :filePath AND pageNumber = :pageNumber")
     suspend fun deleteByPage(filePath: String, pageNumber: Int)
 }

app/src/main/java/com/all/pdfreader/pro/app/room/dao/PdfDocumentDao.kt

@@ -41,6 +41,14 @@ interface PdfDocumentDao {
     @Query("DELETE FROM pdf_documents WHERE filePath = :filePath")
     suspend fun deleteByPath(filePath: String)
 
+    // 批量删除
+    @Query("DELETE FROM pdf_documents WHERE filePath IN (:filePaths)")
+    suspend fun deleteByPaths(filePaths: List<String>)
+
+    // 批量取消收藏，设置isFavorite = 0
+    @Query("UPDATE pdf_documents SET isFavorite = 0 WHERE filePath IN (:filePaths)")
+    suspend fun cancelFavoriteStatus(filePaths: List<String>)
+
     //@Query 会响应flow
     @Query("UPDATE pdf_documents SET filePath = :newFilePath, fileName = :newName WHERE filePath = :oldFilePath")
     suspend fun updateFilePathAndFileName(oldFilePath: String, newFilePath: String, newName: String)
@@ -51,4 +59,7 @@ interface PdfDocumentDao {
     @Query("UPDATE pdf_documents SET lastOpenedTime = :time WHERE filePath = :filePath")
     suspend fun updateLastOpenTime(filePath: String, time: Long)
 
+    @Query("UPDATE pdf_documents SET lastOpenedTime = :time WHERE filePath IN (:filePaths)")
+    suspend fun updateLastOpenTimes(filePaths: List<String>, time: Long)
+
 }

app/src/main/java/com/all/pdfreader/pro/app/room/dao/RecentReadDao.kt

@@ -31,6 +31,10 @@ interface RecentReadDao {
     @Query("DELETE FROM recently_read WHERE filePath = :filePath")
     suspend fun deleteByPdfPath(filePath: String)
 
+    @Query("DELETE FROM recently_read WHERE filePath IN (:filePaths)")
+    suspend fun deleteByPdfPaths(filePaths: List<String>)
+
+
     @Query("DELETE FROM recently_read WHERE lastOpenedTime < :cutoffTime")
     suspend fun deleteOldRecents(cutoffTime: Long)
 }

app/src/main/java/com/all/pdfreader/pro/app/room/repository/PdfRepository.kt

@@ -62,10 +62,14 @@ class PdfRepository private constructor(context: Context) {
     }
 
     //更新最后打开时间，可以设置为0L，相当于更新成未打开过。
-    suspend fun updateLastOpenTime(filePath: String, time: Long) {
+    suspend fun updateLastOpenTime(filePath: String, time: Long = 0L) {
         pdfDao.updateLastOpenTime(filePath, time)
     }
 
+    suspend fun updateLastOpenTimes(filePaths: List<String>, time: Long = 0L) {
+        pdfDao.updateLastOpenTimes(filePaths, time)
+    }
+
     suspend fun updateFavoriteStatus(filePath: String, isFavorite: Boolean) {
         val document = pdfDao.getByPath(filePath)?.copy(
             isFavorite = isFavorite,
@@ -74,6 +78,11 @@ class PdfRepository private constructor(context: Context) {
         document?.let { pdfDao.update(it) }
     }
 
+    //批量取消收藏
+    suspend fun cancelFavorites(filePaths: List<String>) {
+        pdfDao.cancelFavoriteStatus(filePaths)
+    }
+
     suspend fun updateReadingProgress(filePath: String, page: Int, progress: Float) {
         val document = pdfDao.getByPath(filePath)?.copy(
             lastOpenedTime = System.currentTimeMillis(),
@@ -188,6 +197,14 @@ class PdfRepository private constructor(context: Context) {
         noteDao.deleteAllByPdf(filePath)
     }
 
+    // 数据清理集合
+    suspend fun deleteDocuments(filePaths: List<String>) {
+        pdfDao.deleteByPaths(filePaths)
+        recentDao.deleteByPdfPaths(filePaths)
+        bookmarkDao.deleteAllByPdfs(filePaths)
+        noteDao.deleteAllByPdfs(filePaths)
+    }
+
     companion object {
         @Volatile
         private var INSTANCE: PdfRepository? = null

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

@@ -2,6 +2,7 @@ package com.all.pdfreader.pro.app.ui.act
 
 import android.os.Build
 import android.os.Bundle
+import android.os.Environment
 import android.view.View
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.fragment.app.Fragment
@@ -15,18 +16,22 @@ import com.all.pdfreader.pro.app.model.FragmentType
 import com.all.pdfreader.pro.app.room.entity.PdfDocumentEntity
 import com.all.pdfreader.pro.app.ui.dialog.PermissionDialogFragment
 import com.all.pdfreader.pro.app.ui.dialog.ProgressDialogFragment
+import com.all.pdfreader.pro.app.ui.dialog.PromptDialogFragment
 import com.all.pdfreader.pro.app.ui.dialog.SortDialogFragment
 import com.all.pdfreader.pro.app.ui.fragment.FavoriteFrag
 import com.all.pdfreader.pro.app.ui.fragment.HomeFrag
 import com.all.pdfreader.pro.app.ui.fragment.RecentlyFrag
 import com.all.pdfreader.pro.app.ui.fragment.ToolsFrag
 import com.all.pdfreader.pro.app.util.AppUtils.setClickWithAnimation
+import com.all.pdfreader.pro.app.util.AppUtils.setOnSingleClickListener
 import com.all.pdfreader.pro.app.util.PdfScanner
+import com.all.pdfreader.pro.app.util.PdfUtils
 import com.all.pdfreader.pro.app.util.StoragePermissionHelper
 import com.all.pdfreader.pro.app.viewmodel.PdfViewModel
 import com.all.pdfreader.pro.app.viewmodel.observeEvent
 import com.gyf.immersionbar.ImmersionBar
 import kotlinx.coroutines.launch
+import java.io.File
 
 class MainActivity : BaseActivity(), PermissionDialogFragment.PermissionCallback,
     PermissionDialogFragment.CloseCallback, HomeFrag.OnItemLongClickListener,
@@ -136,6 +141,26 @@ class MainActivity : BaseActivity(), PermissionDialogFragment.PermissionCallback
                 }
             }
         }
+        viewModel.fileActionEvent.observeEvent<FileActionEvent.DeleteAll>(this) { event ->
+            when (event.status) {
+                FileActionEvent.DeleteAll.Status.START -> {
+                    progressDialog = ProgressDialogFragment()
+                    progressDialog?.show(supportFragmentManager, "progressDialog")
+                }
+
+                FileActionEvent.DeleteAll.Status.COMPLETE -> {
+                    progressDialog?.dismiss()
+                    progressDialog = null
+                    event.deleteResult?.let {
+                        if (event.deleteResult.success) {
+                            showToast(getString(R.string.delete_successfully))
+                        } else {
+                            showToast(event.deleteResult.errorMessage.toString())
+                        }
+                    }
+                }
+            }
+        }
     }
 
     private fun setupFragments() {
@@ -147,12 +172,12 @@ class MainActivity : BaseActivity(), PermissionDialogFragment.PermissionCallback
 
     //按钮点击事件
     private fun setupNavigation() {
-        binding.homeLlBtn.setOnClickListener { switchFragment(homeFragment) }
+        binding.homeLlBtn.setOnSingleClickListener { switchFragment(homeFragment) }
-        binding.recentlyLlBtn.setOnClickListener { switchFragment(recentlyFragment) }
+        binding.recentlyLlBtn.setOnSingleClickListener { switchFragment(recentlyFragment) }
-        binding.favoriteLlBtn.setOnClickListener { switchFragment(favoriteFragment) }
+        binding.favoriteLlBtn.setOnSingleClickListener { switchFragment(favoriteFragment) }
-        binding.toolsLayoutBtn.setOnClickListener { switchFragment(toolsFragment) }
+        binding.toolsLayoutBtn.setOnSingleClickListener { switchFragment(toolsFragment) }
 
-        binding.pnGoBtn.setOnClickListener {
+        binding.pnGoBtn.setOnSingleClickListener {
             //直接跳转到权限设置页面
             requestPermissions()
         }
@@ -171,13 +196,10 @@ class MainActivity : BaseActivity(), PermissionDialogFragment.PermissionCallback
                 (activeFragment as? SortableFragment)?.onSortTypeChanged(it)
             }).show(supportFragmentManager, TAG)
         }
-        binding.multiSelectBackBtn.setOnClickListener {
+        binding.multiSelectBackBtn.setOnSingleClickListener {
-            homeFragment.exitMultiSelectMode()
+            exitAllMultiSelect()
-            favoriteFragment.exitMultiSelectMode()
-            recentlyFragment.exitMultiSelectMode()
-            updateMultiSelectUi(false, fragmentType)
         }
-        binding.multiSelectAllBtn.setOnClickListener {
+        binding.multiSelectAllBtn.setOnSingleClickListener {
             homeFragment.adapter.toggleSelectAll()
             val isAllSelected = homeFragment.adapter.isAllSelected()
             if (isAllSelected) {
@@ -187,18 +209,56 @@ class MainActivity : BaseActivity(), PermissionDialogFragment.PermissionCallback
             }
             updateSelectNumber(homeFragment.adapter.getSelectedItems().size)
         }
-        binding.multiSelectDeleteBtn.setOnClickListener {
+        binding.multiSelectDeleteBtn.setOnSingleClickListener {
             val selectedItems = homeFragment.adapter.getSelectedItems()
-            logDebug("selectedItems->${selectedItems.size}")
+            if (selectedItems.isNotEmpty()) {
+                val filesToDelete = selectedItems.map { File(it.filePath) }
+                var title = getString(R.string.delete_file_title)
+                var desc = getString(R.string.delete_file_desc)
+                if (selectedItems.size > 1) {
+                    title = getString(R.string.delete_all_file_title)
+                    desc = getString(R.string.delete_all_file_desc)
                 }
-        binding.multiSelectMergeBtn.setOnClickListener {
+                PromptDialogFragment(
+                    title, desc, onOkClick = {
+                        viewModel.deleteFiles(filesToDelete)
+                        exitAllMultiSelect()
+                    }).show(supportFragmentManager, "deleteFiles")
+            }
+        }
+        binding.multiSelectMergeBtn.setOnSingleClickListener {
             logDebug("合并")
+            val selectedItems = recentlyFragment.adapter.getSelectedItems()
+//            if (selectedItems.isNotEmpty()) {
+//                val inputFile = selectedItems.map { File(it.filePath) }
+//                val outputDir = File(
+//                    Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS),
+//                    "PDFReaderPro/merge"
+//                ).apply { if (!exists()) mkdirs() }
+//                PdfUtils.mergePdfFiles(inputFiles = inputFile, outputDir =outputDir, onProgress = {} )
+//            }
         }
-        binding.multiSelectRemoveBtn.setOnClickListener {
+        binding.multiSelectRemoveBtn.setOnSingleClickListener {
-            logDebug("移除最新阅读")
+            val selectedItems = recentlyFragment.adapter.getSelectedItems()
+            if (selectedItems.isNotEmpty()) {
+                val filePaths = selectedItems.map { it.filePath }
+                PromptDialogFragment(
+                    getString(R.string.remove_dialog_title),
+                    getString(R.string.remove_dialog_desc),
+                    getString(R.string.remove),
+                    onOkClick = {
+                        viewModel.removeRecentAll(filePaths)
+                        exitAllMultiSelect()
+                    }).show(supportFragmentManager, "removeRecent")
+            }
+        }
+        binding.multiSelectUnFavoriteBtn.setOnSingleClickListener {
+            val selectedItems = favoriteFragment.adapter.getSelectedItems()
+            if (selectedItems.isNotEmpty()) {
+                val filePaths = selectedItems.map { it.filePath }
+                viewModel.cancelCollectState(filePaths)
+                exitAllMultiSelect()
             }
-        binding.multiSelectUnFavoriteBtn.setOnClickListener {
-            logDebug("移除收藏")
         }
     }
 
@@ -296,6 +356,13 @@ class MainActivity : BaseActivity(), PermissionDialogFragment.PermissionCallback
         }
     }
 
+    private fun exitAllMultiSelect() {
+        homeFragment.exitMultiSelectMode()
+        favoriteFragment.exitMultiSelectMode()
+        recentlyFragment.exitMultiSelectMode()
+        updateMultiSelectUi(false, fragmentType)
+    }
+
     // 授权后续操作
     override fun onPermissionGranted() {
         logDebug("main onPermissionGranted")

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

@@ -19,6 +19,7 @@ import com.all.pdfreader.pro.app.ui.adapter.SplitPdfAdapter
 import com.all.pdfreader.pro.app.ui.adapter.SplitSelectedPdfAdapter
 import com.all.pdfreader.pro.app.ui.dialog.PromptDialogFragment
 import com.all.pdfreader.pro.app.ui.dialog.RenameDialogFragment
+import com.all.pdfreader.pro.app.util.AppUtils.setOnSingleClickListener
 import com.all.pdfreader.pro.app.util.FileUtils.toUnderscoreDateTime
 import com.all.pdfreader.pro.app.util.PdfUtils
 import com.gyf.immersionbar.ImmersionBar
@@ -109,8 +110,8 @@ class SplitPdfActivity : BaseActivity() {
     }
 
     private fun setupClick() {
-        binding.backBtn.setOnClickListener { onBackPressedDispatcher.onBackPressed() }
+        binding.backBtn.setOnSingleClickListener { onBackPressedDispatcher.onBackPressed() }
-        binding.selectAllBtn.setOnClickListener {
+        binding.selectAllBtn.setOnSingleClickListener {
             val selectAll = splitList.any { !it.isSelected }//如果列表里有一页没选中 → 返回 true
             adapter.setAllSelected(selectAll)
             binding.title.text = getString(R.string.selected_page, adapter.getSelPages())
@@ -118,7 +119,7 @@ class SplitPdfActivity : BaseActivity() {
             updateSelectAllState(selectAll)
             updateContinueNowBtnState(selectAll)
         }
-        binding.continueNowBtn.setOnClickListener {
+        binding.continueNowBtn.setOnSingleClickListener {
             val selectedPages = splitList.filter { it.isSelected }.map { it.copy() }
             val name = getString(R.string.split) + "_" + System.currentTimeMillis().toUnderscoreDateTime()
             val item = PdfSelectedPagesItem(filePath, name, selectedPages)
@@ -127,14 +128,14 @@ class SplitPdfActivity : BaseActivity() {
             isSelectedViewShow = true
             updateViewState(true)
         }
-        binding.addBtn.setOnClickListener {
+        binding.addBtn.setOnSingleClickListener {
             binding.continueNowBtn.isEnabled = false//继续按钮不可点击
             updateContinueNowBtnState(false)//重置继续按钮背景
             adapter.setAllSelected(false)
             updateSelectAllState(false)
             updateViewState(false)
         }
-        binding.splitBtn.setOnClickListener {
+        binding.splitBtn.setOnSingleClickListener {
             //因为图片做的路径缓存方式，所以这里直接传入整个集合到result页处理
             val intent = SplitPdfResultActivity.createIntent(this, ArrayList(selectedList))
             startActivity(intent)

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

@@ -35,6 +35,16 @@ import java.util.regex.Pattern
 
 object AppUtils {
 
+    fun View.setOnSingleClickListener(interval: Long = 1000, onClick: (View) -> Unit) {
+        var lastClickTime = 0L
+        setOnClickListener {
+            val now = System.currentTimeMillis()
+            if (now - lastClickTime < interval) return@setOnClickListener
+            lastClickTime = now
+            onClick(it)
+        }
+    }
+
     /**
      * 添加点击动画（点击立即执行逻辑，动画期间禁用点击）
      *

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

@@ -122,6 +122,7 @@ object PdfUtils {
                         newDocument.importPage(document.getPage(pageItem.pageIndex))
                         // 回调进度
                         onProgress?.invoke(index + 1, total)
+                        delay(1)
                     }
                     // 保存新 PDF 文件
                     newDocument.save(outputFile)
@@ -133,4 +134,50 @@ object PdfUtils {
             null
         }
     }
+
+    /**
+     * 合并多个 PDF 文件到一个新的 PDF 文件
+     *
+     * 使用 PDFBox 的 PDDocument 合并多个 PDF，支持进度回调。
+     * 避免直接生成缩略图，以保持原 PDF 的矢量质量。
+     *
+     * @param inputFiles     要合并的 PDF 文件列表
+     * @param outputDir      输出目录，如果不存在会自动创建
+     * @param outputFileName 输出文件名，例如 "merged.pdf"
+     * @param onProgress     可选回调，当前处理进度 (current 文件, total 文件)
+     * @return               新生成的 PDF 文件，失败返回 null
+     */
+    suspend fun mergePdfFiles(
+        inputFiles: List<File>,
+        outputDir: File,
+        outputFileName: String,
+        onProgress: ((current: Int, total: Int) -> Unit)? = null
+    ): File? = withContext(Dispatchers.IO) {
+
+        if (inputFiles.isEmpty()) return@withContext null
+        if (!outputDir.exists()) outputDir.mkdirs()
+        val outputFile = File(outputDir, outputFileName)
+
+        try {
+            PDDocument().use { mergedDocument ->
+                val totalFiles = inputFiles.size
+                inputFiles.forEachIndexed { index, file ->
+                    PDDocument.load(file).use { doc ->
+                        for (page in doc.pages) {
+                            mergedDocument.addPage(page)
+                        }
+                    }
+                    // 回调进度：按文件计数，也可以按总页数进一步精细化
+                    onProgress?.invoke(index + 1, totalFiles)
+                    delay(1) // 给 UI 更新留点时间
+                }
+                mergedDocument.save(outputFile)
+            }
+            outputFile
+        } catch (e: Exception) {
+            e.printStackTrace()
+            null
+        }
+    }
+
 }

app/src/main/java/com/all/pdfreader/pro/app/viewmodel/PdfViewModel.kt

@@ -7,6 +7,7 @@ import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.all.pdfreader.pro.app.PRApp
+import com.all.pdfreader.pro.app.model.DeleteResult
 import com.all.pdfreader.pro.app.model.FileActionEvent
 import com.all.pdfreader.pro.app.room.entity.BookmarkEntity
 import com.all.pdfreader.pro.app.room.entity.PdfDocumentEntity
@@ -88,6 +89,30 @@ class PdfViewModel : ViewModel() {
         }
     }
 
+    fun deleteFiles(files: List<File>) {
+        viewModelScope.launch {
+            _fileActionEvent.postValue(FileActionEvent.DeleteAll(FileActionEvent.DeleteAll.Status.START))
+            val deleteResult = withContext(Dispatchers.IO) {
+                try {
+                    val result = FileDeleteUtil.deleteFiles(files)
+                    if (result.success) {
+                        // 批量清理数据库
+                        val paths = files.map { it.absolutePath }
+                        pdfRepository.deleteDocuments(paths)
+                    }
+                    result
+                } catch (e: Exception) {
+                    DeleteResult.failure(e.message ?: "Unknown error")
+                }
+            }
+            _fileActionEvent.postValue(
+                FileActionEvent.DeleteAll(
+                    FileActionEvent.DeleteAll.Status.COMPLETE, deleteResult
+                )
+            )
+        }
+    }
+
     fun saveCollectState(filePath: String, isFavorite: Boolean) {
         viewModelScope.launch {
             pdfRepository.updateFavoriteStatus(filePath, isFavorite)
@@ -95,6 +120,13 @@ class PdfViewModel : ViewModel() {
         }
     }
 
+    fun cancelCollectState(filePaths: List<String>) {
+        viewModelScope.launch {
+            pdfRepository.cancelFavorites(filePaths)
+            _fileActionEvent.postValue(FileActionEvent.Favorite(false))
+        }
+    }
+
     fun duplicateFile(context: Context, filePath: String) {
         viewModelScope.launch {
             val file = FileUtils.duplicateFile(File(filePath))
@@ -214,7 +246,7 @@ class PdfViewModel : ViewModel() {
         }
     }
 
-    fun gotoPage(number: Int){
+    fun gotoPage(number: Int) {
         viewModelScope.launch {
             _fileActionEvent.postValue(FileActionEvent.GotoPage(number))
         }
@@ -222,7 +254,13 @@ class PdfViewModel : ViewModel() {
 
     fun removeRecent(filePath: String) {
         viewModelScope.launch {
-            pdfRepository.updateLastOpenTime(filePath, 0L)
+            pdfRepository.updateLastOpenTime(filePath)
+        }
+    }
+
+    fun removeRecentAll(filePaths: List<String>) {
+        viewModelScope.launch {
+            pdfRepository.updateLastOpenTimes(filePaths)
         }
     }
 

app/src/main/res/layout/fragment_favorite.xml

@@ -26,7 +26,7 @@
             style="@style/TextViewFont_PopMedium"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:text="@string/no_files_yet"
+            android:text="@string/no_favorites_yet"
             android:textColor="#B6BFCC"
             android:textSize="20sp" />
     </LinearLayout>

app/src/main/res/layout/fragment_recently.xml

@@ -26,7 +26,7 @@
             style="@style/TextViewFont_PopMedium"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:text="@string/no_files_yet"
+            android:text="@string/no_recent_reads_yet"
             android:textColor="#B6BFCC"
             android:textSize="20sp" />
     </LinearLayout>

app/src/main/res/values/strings.xml

@@ -97,6 +97,8 @@
     <string name="error_cannot_delete_protected_directory">Cannot delete protected system directory</string>
     <string name="delete_file_title">Delete this file permanently?</string>
     <string name="delete_file_desc">Deleting this file will remove it permanently from your device.</string>
+    <string name="delete_all_file_title">Delete selected files permanently?</string>
+    <string name="delete_all_file_desc">Deleting the selected files will remove them permanently from your device.</string>
     <string name="file_information">File Information</string>
     <string name="file_information_desc">Everything you need to know about the file.</string>
     <string name="last_modified">Last Modified</string>
@@ -122,6 +124,8 @@
     <string name="delete_bookmarks_desc">Are you sure you want to delete all Bookmarks?</string>
     <string name="bookmark_loading">Loading bookmarks, please try again later</string>
     <string name="no_files_yet">no files yet</string>
+    <string name="no_favorites_yet">No favorites yet</string>
+    <string name="no_recent_reads_yet">No recent reads yet</string>
     <string name="split_pdf">Split PDF</string>
     <string name="split">Split</string>
     <string name="merge_pdf">Merge PDF</string>