Crash when dragging the swipe action cell item out of screen

[gliese667c]

════════ Exception caught by widgets library ═══════════════════════════════════
The following NoSuchMethodError was thrown building Container(bg: BoxDecoration(color: Color(0xff050505)), margin: EdgeInsets(1.0, 0.0, 1.0, 0.0)):
The getter 'position' was called on null.
Receiver: null
Tried calling: position

The relevant error-causing widget was
    Container 
When the exception was thrown, this was the stack
#0      Object.noSuchMethod  (dart:core-patch/object_patch.dart:51:5)
#1      _SwipeActionCellState._addScrollListener 
package:flutter_swipe_action_cell/core/swipe_action_cell.dart:207
#2      _SwipeActionCellState.didChangeDependencies 
package:flutter_swipe_action_cell/core/swipe_action_cell.dart:191
#3      StatefulElement._firstBuild 
package:flutter/…/widgets/framework.dart:4716
#4      ComponentElement.mount 
package:flutter/…/widgets/framework.dart:4531
...
════════════════════════════════════════════════════════════════════════════════

════════ Exception caught by widgets library ═══════════════════════════════════
'package:flutter/src/widgets/framework.dart': Failed assertion: line 5028 pos 14: '_dependents.isEmpty': is not true.
The relevant error-causing widget was
    MediaQuery 
lib/main.dart:98
════════════════════════════════════════════════════════════════════════════════

════════ Exception caught by scheduler library ═════════════════════════════════
Cannot get size from a render object that has not been through layout.
════════════════════════════════════════════════════════════════════════════════

[luckysmg]

Can you give me your demo code? I just cant reproduce your problem.. @gliese667c

[luckysmg]

I guess that you put cell in a widget that is not scrollable .You should put cells in ListView or CustomScrollView....instead of Column...@gliese667c

[gliese667c]

No, I put it in ReorderableListView, the long-press cell will crash the app.
Reproduce Code

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter_swipe_action_cell/core/swipe_action_cell.dart';

void main() async {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: Page1(
        title: "haha",
      ),
    );
  }
}

class Page1 extends StatefulWidget {
  Page1({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _Page1State createState() => _Page1State();
}

class _Page1State extends State<Page1> {
  List list;

  @override
  void initState() {
    super.initState();
    list = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: ReorderableListView(
        onReorder: (_, __) {},
        children: _buildList(),
      ),
    );
  }

  List<Widget> _buildList() {
    return List.generate(list.length, (index) => _item(index));
  }

  Widget _item(int index) {
    return SwipeActionCell(
      ///this key is necessary
      key: ObjectKey(list[index]),

      ///this is the same as iOS native
      performsFirstActionWithFullSwipe: true,
      actions: <SwipeAction>[
        SwipeAction(
            title: "delete",
            onTap: (CompletionHandler handler) async {
              await handler(true);
              list.removeAt(index);
              setState(() {});
            },
            color: Colors.red),
        SwipeAction(
            widthSpace: 120,
            title: "popAlert",
            onTap: (CompletionHandler handler) async {
              ///false means that you just do nothing,it will close
              /// action buttons by default
              handler(false);
              showCupertinoDialog(
                  context: context,
                  builder: (c) {
                    return CupertinoAlertDialog(
                      title: Text('ok'),
                      actions: <Widget>[
                        CupertinoDialogAction(
                          child: Text('confirm'),
                          isDestructiveAction: true,
                          onPressed: () {
                            Navigator.pop(context);
                          },
                        ),
                      ],
                    );
                  });
            },
            color: Colors.orange),
      ],
      child: Padding(
        padding: const EdgeInsets.all(8.0),
        child: Text("this is index of ${list[index]}", style: TextStyle(fontSize: 40)),
      ),
    );
  }
}

[luckysmg]

Thanks for your response. I will try your code to find problem.

[luckysmg]

I have pushed a new version of this package (1.0.3+1). You can try again.@gliese667c

[luckysmg]

I will close this issue . If there are problems remains , you can reopen this issue whenever you want