优化

app/src/main/java/io/legado/app/ui/book/read/ReadBookActivity.kt

@@ -312,8 +312,6 @@ class ReadBookActivity : BaseReadBookActivity(),
         upSystemUiVisibility()
         if (hasFocus) {
             binding.readMenu.upBrightnessState()
-        } else if (!menuLayoutIsVisible) {
-            ReadBook.cancelPreDownloadTask()
         }
     }
 
@@ -323,6 +321,12 @@ class ReadBookActivity : BaseReadBookActivity(),
         binding.readView.upStatusBar()
     }
 
+    override fun onTopResumedActivityChanged(isTopResumedActivity: Boolean) {
+        if (!isTopResumedActivity) {
+            ReadBook.cancelPreDownloadTask()
+        }
+    }
+
     @SuppressLint("UnspecifiedRegisterReceiverFlag")
     override fun onResume() {
         super.onResume()
@@ -358,7 +362,6 @@ class ReadBookActivity : BaseReadBookActivity(),
         autoPageStop()
         backupJob?.cancel()
         ReadBook.saveRead()
-        ReadBook.cancelPreDownloadTask()
         unregisterReceiver(timeBatteryReceiver)
         upSystemUiVisibility()
         if (!BuildConfig.DEBUG) {