优化

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

@@ -88,10 +88,8 @@ object DocumentUtils {
         val docList = arrayListOf<DocItem>()
         var c: Cursor? = null
         try {
-            val childrenUri = DocumentsContract.buildChildDocumentsUriUsingTree(
-                uri,
-                DocumentsContract.getDocumentId(uri)
-            )
+            val childrenUri = DocumentsContract
+                .buildChildDocumentsUriUsingTree(uri, DocumentsContract.getDocumentId(uri))
             c = context.contentResolver.query(
                 childrenUri, arrayOf(
                     DocumentsContract.Document.COLUMN_DOCUMENT_ID,
@@ -107,7 +105,7 @@ object DocumentUtils {
                 val sci = c.getColumnIndex(DocumentsContract.Document.COLUMN_SIZE)
                 val mci = c.getColumnIndex(DocumentsContract.Document.COLUMN_MIME_TYPE)
                 val dci = c.getColumnIndex(DocumentsContract.Document.COLUMN_LAST_MODIFIED)
-                c.moveToFirst()
+                if (c.moveToFirst()) {
                     do {
                         val item = DocItem(
                             name = c.getString(nci),
@@ -119,6 +117,7 @@ object DocumentUtils {
                         docList.add(item)
                     } while (c.moveToNext())
                 }
+            }
         } catch (e: Exception) {
             e.printStackTrace()
         } finally {