优化

app/src/main/java/io/legado/app/ui/book/read/page/delegate/PageDelegate.kt

@@ -83,11 +83,9 @@ abstract class PageDelegate(protected val readView: ReadView) {
 
     protected fun stopScroll() {
         isStarted = false
-        readView.post {
         isMoved = false
         isRunning = false
-            readView.invalidate()
-        }
+        readView.postInvalidate()
     }
 
     @CallSuper
@@ -193,11 +191,13 @@ abstract class PageDelegate(protected val readView: ReadView) {
     fun postInvalidate() {
         if (isRunning && this is HorizontalPageDelegate) {
             readView.post {
+                if (isRunning) {
                     setBitmap()
                     readView.invalidate()
                 }
             }
         }
+    }
 
     open fun onDestroy() {
         // run on destroy