优化代码

app/src/main/java/io/legado/app/help/BookHelp.kt

@@ -52,7 +52,7 @@ object BookHelp {
             App.db.bookDao().all.forEach {
                 bookFolderNames.add(it.getFolderName())
             }
-            val file = FileUtils.getDirFile(downloadDir, cacheFolderName)
+            val file = FileUtils.getFile(downloadDir, cacheFolderName)
             file.listFiles()?.forEach { bookFile ->
                 if (!bookFolderNames.contains(bookFile.name)) {
                     FileUtils.deleteFile(bookFile.absolutePath)

app/src/main/java/io/legado/app/help/CrashHandler.kt

@@ -142,7 +142,7 @@ class CrashHandler : Thread.UncaughtExceptionHandler {
             val time = format.format(Date())
             val fileName = "crash-$time-$timestamp.log"
             mContext?.externalCacheDir?.let { rootFile ->
-                FileUtils.getDirFile(rootFile, "crash").listFiles()?.forEach {
+                FileUtils.getFile(rootFile, "crash").listFiles()?.forEach {
                     if (it.lastModified() < System.currentTimeMillis() - TimeUnit.DAYS.toMillis(7)) {
                         it.delete()
                     }

app/src/main/java/io/legado/app/help/storage/Backup.kt

@@ -18,7 +18,7 @@ import java.util.concurrent.TimeUnit
 object Backup {
 
     val backupPath: String by lazy {
-        FileUtils.getDirFile(App.INSTANCE.filesDir, "backup").absolutePath
+        FileUtils.getFile(App.INSTANCE.filesDir, "backup").absolutePath
     }
 
     val backupFileNames by lazy {

app/src/main/java/io/legado/app/utils/FileUtils.kt

@@ -54,11 +54,6 @@ object FileUtils {
         return File(filePath)
     }
 
-    fun getDirFile(root: File, vararg subDirs: String): File {
-        val filePath = getPath(root = root, *subDirs)
-        return File(filePath)
-    }
-
     fun getPath(root: File, vararg subDirFiles: String): String {
         val path = StringBuilder(root.absolutePath)
         subDirFiles.forEach {