Merge pull request #250 from jamesblasco/fix/will_pop_close

fix/will_pop_closure

@@ -224,24 +224,27 @@ class _ModalBottomSheetState extends State<ModalBottomSheet>
     // ignore: unawaited_futures
     // ignore: unawaited_futures
     _bounceDragController.reverse();
     _bounceDragController.reverse();
 
 
-    var canClose = true;
+    Future<void> tryClose() async {
       if (widget.shouldClose != null) {
       if (widget.shouldClose != null) {
         _cancelClose();
         _cancelClose();
-      canClose = await shouldClose();
-    }
+        bool canClose = await shouldClose();
         if (canClose) {
         if (canClose) {
+          _close();
+        }
+      } else {
+        _close();
+      }
+    }
+
     // If speed is bigger than _minFlingVelocity try to close it
     // If speed is bigger than _minFlingVelocity try to close it
     if (velocity > _minFlingVelocity) {
     if (velocity > _minFlingVelocity) {
-        _close();
+      tryClose();
     } else if (hasReachedCloseThreshold) {
     } else if (hasReachedCloseThreshold) {
       if (widget.animationController.value > 0.0) {
       if (widget.animationController.value > 0.0) {
         // ignore: unawaited_futures
         // ignore: unawaited_futures
         widget.animationController.fling(velocity: -1.0);
         widget.animationController.fling(velocity: -1.0);
       }
       }
-        _close();
-      } else {
-        _cancelClose();
-      }
+      tryClose();
     } else {
     } else {
       _cancelClose();
       _cancelClose();
     }
     }