Unable to place Slider in Dialog

[niklasarnitz]

trafficstars

Problem:

The App throws an exception when the Slider should be shown inside an Dialog.

Exception:

https://pastebin.com/yy3Uqt6j

flutter doctor -v

flutter doctor -v                                       
[✓] Flutter (Channel stable, 1.20.3, on Mac OS X 10.15.6 19G2021, locale en-GB)
    • Flutter version 1.20.3 at /Users/niklas/personal/dev/flutter
    • Framework revision 216dee60c0 (3 weeks ago), 2020-09-01 12:24:47 -0700
    • Engine revision d1bc06f032
    • Dart version 2.9.2

 
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.1)
    • Android SDK at /Users/niklas/Library/Android/sdk
    • Platform android-30, build-tools 30.0.1
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 11.7)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 11.7, Build version 11E801a
    • CocoaPods version 1.9.3

[✓] Android Studio (version 4.0)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 49.0.2
    • Dart plugin version 193.7547
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] VS Code (version 1.49.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.14.1

[✓] Connected device (1 available)
    • iPhone 11 (mobile) • EB2F22AE-46AF-456E-9BC2-ADF2423F82C3 • ios • com.apple.CoreSimulator.SimRuntime.iOS-13-7 (simulator)

Code:

(There may be one ')' to much..)

showDialog(
      context: context,
      builder: (BuildContext context) {
        return AlertDialog(
          title: Text("Filteroptionen Auswählen"),
          content: Column(
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              // Altersgruppe
              ExpansionTile(
                title: Text("Gruppengröße"),
                children: [
                    FlutterSlider(
                      values: [
                        getLowerBound() / 2,
                        getUpperBound() / 2,
                      ],
                      min: getLowerBound(),
                      max: getUpperBound(),
                      onDragCompleted: (handlerIndex, lowerValue, upperValue) {
                        setState(() {
                          _lowerAlterValue = lowerValue;
                          _upperAlterValue = upperValue;
                        });
                      },
                    ),
                  ),
                ],
              ),
            ],
          ),
        );
      },
    );